Dave, don't be blinded by the v.i., you (sorry, the fork oil producers) can influence it relatively easily with dopes (just look at shock oil with v.i. of even 400, they get really hot especially the ttx shocks with their small amount of oil). there are also things such as foaming behavior that strongly influence the operation of the dampers, cavitation etc. The viscosity is where you calibrate your dampers with the shims on and as such the 40 cSt is the most important for the "normal" users.

@CatalystReactionSBW

3 жыл бұрын

Excellent contribution, thank you.

This video was awesome, highly detailed but simplified enough for general understanding!!

Thands Dave. Lots of useful information there. Will try that out with next fork seal change.

Centistokes and kinematic viscosity are the same. Centistokes is just the unit to measure kinematic viscosity like metres are used to measure length. en.m.wikipedia.org/wiki/Viscosity

Thanks Dave, that was really helpful, I now know what I'm going to try next time I change the fork oil.

thanks a lot dave . this one answered a lot of questions i had about the drop in viscosity of my MOTUL oils as things heat up. 20w sheds viscosity way sooner than 10w and i always wondered why. i ride a Royal enfield Himalayan on the dirt every weekend. pretty gnarly stuff and at good pace too.

Great video, Dave educating most of us .

Big thumbs up for a full vid of such an interesting subject. I use Belray 10w on my FJR 1300.. UK weather temps.. loaded panniers..96kilo rider. Progressive riding. Fork oil changes at 10k miles max for me.

Thank you, I'm glad I became a member! Really great info. I thought switching brands between W numbers was really similar! Doh!

Brilliant explanation to consolidate what I sort of knew. Multistrada 1200, regularly 35+ Celsius climate, 110kg rider, ridden pretty hard and running out of fork valving adjustment so I think it's time to move to a heavier more stable oil than the 7.5w Shell.

Dave, you asked me at Thunderhill if I had 20W in my forks. Now I understand why.

Excellent info and explanation, thanks.

I feel smarter every time I watch your videos Dave. Thank you

@groundsurvivalstudygracieg4034

Жыл бұрын

Andrew Wiltse?? The famous Jiu-Jitsu blackbelt competitor??

Thanks, Dave! As I prep to replace my bushes and seals, its time for an oil change. Your videos always keep me pointed in the right direction. As California summer track days near, I plan to change from a 10w(spec) to a 15w on my stock 03 z1000. Hope to see you out at Thunderhill soon to pick your brain about this.

@CatalystReactionSBW

3 жыл бұрын

That will b a great choice, stick with Maxima or Motul

Thanks Dave! Very informative.

Thanks. Local tuner recommended Ohlins 7.5w, but the cost and extra deliverytime wasnt an option, so i used those online charts and cst values to find closests to Ohlins. Ended using Honda 5w.

@LostInADV

5 ай бұрын

Is there a “go-to” online chart?

Great video Dave as usual... ... ... ..... .......

Thanks for the super clear explanation 🙌🏼

tq so much sir,this realy helps me which is only 42kg(abnormal) of weight to have fun riding

Wow, finally the yt algorithm throws me up a decent channel. Thamks so much for your time and info Dave, new subscriber here, great knowledge well presented with just that hint of sarcasm so sadly missing from so many others lol. Cheers man 👍

Thank you for this!

Thank you Dave, you are master!!

Brilliant explanation.

From Philippines 🇵🇭 😊 Thank you for Sharing 🙂

Thank you so much !! Great and perfect crystal clear info. Very valuable and a level up on fine tune your forks.

@CatalystReactionSBW

7 ай бұрын

I appreciate you watching and thanks for the kind words! Glad you enjoyed the content.

Thanks! This added my knowledge with oils.

@CatalystReactionSBW

Жыл бұрын

Glad that was good content for you to leverage!

2009 Victory Vision. Very heavy bike. Swapped out fork oil for Redline 10wt. Quantity to spec. Very stable behavior and just fine. So far so good, FWIW.

@CatalystReactionSBW

Жыл бұрын

Thank you for posting Karl. It is worth a lot to fellow Victory owners! I appreciate you paying it forward!

I can't read the owner's manual because the forks on my 1967 Kawasaki are actually from an Unknown 80cc MX bike, probably early 80s. The forks have no brand markings and were pulled out of a heap of "old cycle parts" in the 90s. So we have to fall back on first principles with these. They work pretty well on ATF+4, (which I'm told is roughly equivalent to like a 7w fork oil?) but sure do leak a lot with it. Lol

Springs and proper oil at the correct level will transform your bike and greatly improve your riding experience. The difference is amazing

Thank you Dave!! I have no -adjustable forks and live in Las Vegas. Will be swapping out the factory oil to Maxima 20W for my weekend spirited rides and track days. Not a commuter bike.

@CatalystReactionSBW

2 ай бұрын

Thank you for wanting to learn, understand what is needed and get the job done!

Nice Start Dave, love your intro..set the stage, let's be nice and helpful.. cool man cool

@CatalystReactionSBW

Жыл бұрын

Thanks!

Leadership by example?!!! Yeah, we were taught the same pay it forward attitude. Will do, chief! Hope you and all do yours have a nice 21 summer season. 😉

Having previously made the mistake of assuming a higher V.I. Is always better and finding out that as the viscosity index goes up the lubricity goes down, as a general rule. Therefore high index oil are best for cartridge dampers and avoided for open bath lubrication. I personally damaged a great fork making this mistake

@CatalystReactionSBW

Жыл бұрын

Thanks for sharing your knowledge and experience Angus!

Hi Dave, you helped me set up my f&r suspension on my 2020 1050XT Suzuki V-Strom via email about a year ago when i got it new. It is really dialed and I love it thanks to your excellent advice. I will be doing my winter service now, including the dump & run on the fork oil. I ride a very spirited pace in the mountains, weigh 164 lbs. w/o gear and carry probably 25 lbs. gear. Based on the CST charts, I am thinking Maxima 7.5W is right. Can I set my oil level/air gap without disassembling and removing springs? My riding temps will vary from 90f-40f. Many thanks as always!!!

Interesting video, having just cleaned/serviced the forks on my Aprilia Pegaso Strada (commuter) and changed to 15W. On the West Coast of Scotland, which was dry (Woo Hoo) the difference was very noticeable in both compression and rebound damping and I could ride a lot harder/faster with improved feedback. Heading back to Edinburgh, due to rain and average speed camera's the change wasn't so noticeable. I'll keep notes and try 20W the next time.

@CatalystReactionSBW

3 жыл бұрын

Nice work! Thank you for sharing your experience and results.

@Abdal-RahmanI

Жыл бұрын

Thanks for sharing! I have a Strada as well and was planning to do similar changes :)

dave: "the W stands for winter" also dave: 8:38 :D thank you for another informative video

I got Motul 10W for my Street Triple 765 R 2018 w. Showa SFF BPF. Feels kinda identical to the Showa SS47. Till now...

I'm old enough to remember when Japanese manufactuers used fish oil in damer rod forks......and you think well used modern fork oil stinks, well you haven't lived.

@jenpsakiscousin4589

2 жыл бұрын

I remember tearing into an old Hodaka fork and man, smelled worse than rotten cat food and sour milk

@Melody-eu4qu

Жыл бұрын

M

@chrisrydoinstuff8525

Жыл бұрын

All my 70s and 80s bikes call for ATF in the forks are fluid, that sticks but not like fish oil.

@richardcurtis114

3 ай бұрын

KYB oil stinks when it's fresh. But when it used.........aghhh

Thermal coefficient of expansion is involved too. Oil volume expands with heat, contracts with cold. Not so much a factor for forks that already have an air gap or motor oil in a crankcase but expansion affects smaller volumes much more. This is why reservoirs for brake master cylinders or steering stabilizers have to have an air gap to work right.

I know what type of oil i need, but you got my attention with that funny pun in the title

SV 650 Gen 1, classic damping fork rod Spirited road driving above 24 C, pilot 85 to 90 Kg. Stock springs: Motul 15W, a bit too thin for rebound. WP spring: Motul 20W good rebound (need a bit of tuning for the oil level/air gap to prevent harshness on compression).

@CatalystReactionSBW

Жыл бұрын

Thank you for sharing your R&D on the work done so far. A tip of the hat to you!

Amazing info. Thx!

@CatalystReactionSBW

4 ай бұрын

Thanks for watching glad you enjoyed it.

Ive been thinking about fork oil recently as I need to change it on 4 bikes. I reckon hydraulic fluid would be more than suitable and it is tightly regulated. In its normal application it has to withstand very severe operating conditions, so I doubt it would struggle with bike forks. It also comes in mineral and synthetic types.

@ckkrons2338

2 жыл бұрын

Fork oil isn't that expensive to experiment with four bikes.

@andrewberg2361

2 жыл бұрын

ATF is what was used before 'fork oil' was invented . Workshop manual of my Triumph lists the brand and type of ATF to use . Works a treat .

This is so damn helpful! The details and how you explained it helped me understand whcih oil grade to use. I have studied this in college, over 2 decades ago and totally forgot it hahaha Was trying to figure out what WT to use on my MTB fork and now I know. Thank you so much!

I've got a 22 CRF 450 and when I got it the forks were solid to move so I got the lightest spring rate from honda and rebuild them to find it's already got the lightest spring in it! I used the correct oil and levels the manufacturer states but it's still a harsh ride I've checked the fork alignment many times and my adjustments are opened right up but it's still crap but I'm about to send the top tubes for a regrind and anodising so I'm trying 5w when I rebuild them this time

@CatalystReactionSBW

Ай бұрын

I would suggest that you take the chrome and outer tubes and have them put into a lathe and tested for run out to see if the tubes are binding. I would check the bushing as well and look at the chrome tubes for scoring from the bushings.

It was all very simple when Dave said: RTFM! Then he started with the numbers and i got completely lost. I will stick with RTFM.

Dave you the man.. and have u watched that video twist of the wrist 2 video...by Keith code

Is this numbers for the motul synthetic factory line fork oil? Or the cheaper mineral based fork oils.? Is maxima fork oil synthetic? The 2011 gsxr 1000 has the SS-05 for oil stock which is showa 5W not sure if it's synthetic ...would the motul factory line synthetic 5w be a better replacement oil at fork oil service time or should I stick with the suzuki showa SS-05...?

Thought I was with ya but you said two things that appeared to conflict, and I got confused. First, faster pace riders (weekend twisty road enthusiast vs commuter) might need a lower weight oil, and second that a rider on an MT07 who rides hard on the weekends may prefer the 20w over the 15. I have an MT07 as my first bike, and I've been progressing quickly in my riding, and I've begun thinking about simple/cost effective modifications I can make to suit me better and learn more about motorcycling in general. The suspension is a gripe I hear of continually but, being that it's all I've known, I don't know WHAT I don't know, and I've been wanting to try changing to a different fork oil to see what it does to the handling and whether it's an improvement for me or not. I like to ride briskly (Top of third gear into fourth ~60-80mph in every straight possible between the curves) and brake moderately hard, not at track pace of course - but about as hard as is feasibly safe on public back roads. I weigh 190 pounds and live in an area with a riding season temperature range between about 40 and 95 degrees Fahrenheit. I'm not sure what the best choice could be.

@CatalystReactionSBW

Жыл бұрын

Thank you for your comment. For cartridge forks, sometimes thinner oil is needed for better flow and handling as there are adjusters to use. For damping rod forks thicker oil is needed to create more controlled rebound. With your MT07, 15 or 20w oil will make an enormous difference and start your journey of changes that create positives vs adapting to suspension.

A lot to take into consideration, fun to tinker with however. Thank you so much for this work! Do you have experience with the Tracer 900? What oil would you choose for spirited riding for a 75 KG's rider that typically ride between 10-25 degrees celcius?

@CatalystReactionSBW

2 жыл бұрын

I have one in NZ and did all the work on it there in a relatively cold climate. 10w for rebound and 15w for compression. All that work is posted on my website at www.davemosstuning.com and search Tracer GT and "The Long Haul" articles for OEM settings, geometry etc.

Peter verdone has a chart that's it's weight in gold , and if you know how to chart it onto sheets/excel, it's like sniping a toothpick from a mile away , it's that powerful of a tool.

@CatalystReactionSBW

3 жыл бұрын

100% agree.

@platinumgrit

11 ай бұрын

Peter Verdone is a legend.

Dave you should watch a Project Farm oil test with his flow check of new vs used oils (like a pinewood derby track). Would be interesting to do with various folk oils at hot and cold temps.

Oh my Gosh! I can't believe how little I knew about fork oil! Thank you so much for showing me that there is a real measure of viscosity. I just rebuilt the forks on my 2008 GL1800 and added Progressive springs. I'm still trying to decide what fork oil to use. I suspect that I want something a bit heavier than the 10w OE oil made by Showa. If it wasn't such a pain to drain and swap fluid, I would just go in with Maxima Racing 15w and try it out. I have even though about mixing 15w with 10w to get 12.5w. Would you be kind enough to give me some guidance?

@CatalystReactionSBW

7 ай бұрын

Thank you for your comment and kind words. May I suggest going straight to 15w for your generation of Goldwing. Use the stock volume in the service manual and compare to what you extract prior to deciding how much to put back in. You should notice a small loss post draining compared to the manual amount. Please take that into account.

(At least fork oils that I’m familiar) are tested according to ASTM D445 for viscosity both 40C and 100C temperatures. Since this is single grade W( winter) rated oil, SAE W viscosity rating is based on -30C(?). For e.g 10W oil can have 32 or 54 mm2 at 40C (these are real values, not just theoretical example). I also recommended always checking fork oil datasheets from manufacturer’s website (typically acc. to standard it is required to have and show both; technical datasheet and safety datasheet), since it list both 40C and 100C values. Both values matter, but 40C value is more important. No don’t work directly at petro-chemical industry and I don’t know ASTM 445 or SAE standards well (but I know ton of other standards), so hopefully someone expert on these standards could correct me if I’m wrong. Great Video Dave.

The St (Stoke) and by extension cSt (centiStoke) are the non-SI units of kinematic viscosity. The SI unit is m^2/s. But fundamentally they're measuring the same thing and the conversion is very simple - 1 cSt = 1 mm^2/s or 1e-6 m^2/s. Kinematic viscosity itself is a derivative quantity. It is the ratio of dynamic viscosity and density (nu = mu/rho). In hydraulic dampers, where the important property of a fluid is its resistance to flow through an orifice, kinematic viscosity is the right quantity to work with as it neatly abstracts away the interaction between density and viscosity in this type of flow. Doesn't hurt that fork oil is more or less incompressible either.

@mfitzgerald130

8 ай бұрын

Fantastic knowledge you have , incompressible is a new word for me.👍can I ask, are a motorbikes front forks basically a hydraulic ram with a internal spring? If so , as someone else previous mentioned can I use hydraulic fluid in the bikes front forks?

@233kosta

8 ай бұрын

@@mfitzgerald130 Part of the job - I work in thermo/fluid dynamics. It's super interesting stuff, but you've got to have the patience to go to the depth necessary, otherwise none of it makes sense. Anyway, back to forks... They're not really hydraulic rams in the excavator sense. They're dampers. They dampen oscillations (i.e. take the bounce out of the system) by forcing oil through a small orifice (or a few, or an annular gap... another big word to learn 😉) any time there is motion. The resistance of the fluid pushing through is proportional to the rate at which it's being forced through (closer to a square relationship, actually), so it works really well at taking away oscillatory motion. It does however rely on the properties of that oil, specifically on its kinematic viscosity. Too much will overdamp the system and too little will leave it bouncy. The latter, famously, being a problem on MT-07s from the factory. To that end, it's usually best to follow manufacturer recommendations here, as they've done the R&D to determine the correct grade and more importantly, the correct type of oil to use there. Or at least they should have (see MT-07). Hydraulic, automatic transmission and fork oils are generally related, insofar as they're all hydraulic working fluids, but I suspect they're different enough that using regular hydraulic oil probably won't yield the best results (plus that sh!t will kill you if it enters your blood stream, NASTY!!!). Inside, forks are made of a few metals, some plastics, and rubber, which is broadly similar to automatic transmissions and hydraulic systems, so it's _possible_ that using a different type of oil (like ATF) wouldn't damage anything, but I wouldn't risk it. Too much can go wrong even if your forks are just out of whack rather than outright damaged. The "spring" part is actually two springs - the coil spring you pull out when you service the thing, and an air spring made of the air gap above the oil. As you compress the forks and thus pump oil into that void, its air volume decreases (because it was filled by oil), so the air must compress (usually they're sealed). Then when the fork extends the air can expand again. Effectively a gas spring. That's why oil level in your forks is important, and why you can change their spring properties by adding and removing oil.

@mfitzgerald130

8 ай бұрын

Thankyou Kosta,I appreciate you clearing that up for me and hopefully for many other motorbike riders.👍✨💫

Still confused.... lol Bought a 2021 mt07. 215lb rider. No track riding. Just a weekend rider (Toronto, Canada) Not sure if bike is delivered to the dealer with fork oil, but if it isn't, should I ask the dealer to put a specific W fluid in? Picking up bike end of month/early July. Love the videos DMT!

@CatalystReactionSBW

3 жыл бұрын

20w for you, stock volume.

Great info as always. I have a Moto Guzzi Audace cruiser, 660lb bike + 200lb rider. I'm just about to get my mechanic to upgrade the OEM front and rear suspension to Matris suspension. What weight fork oil do cruisers usually run? I'm looking for sportier more responsive feedback riding at 15°C to 30°C temps.

@CatalystReactionSBW

2 жыл бұрын

Matris gives you oil specs and volume for the forks and in general they use 5w or 10w based on the internal piston orifice size.

@Audace1400

2 жыл бұрын

@@CatalystReactionSBW Thanks for your feedback. 🍺🍺🍺

useful video: Question: I know what temperature rear shock oils can and do reach but, not seen figures for 'in use' front fork oil....I'm taking an educated guess in that it's over ambient so that negates worries over regional temperatures.....wouldn't it? ....damper rod front forks typically have a longer stroke than a rear end but, a higher oil capacity and out in the air stream. It can't be that high as I've never seen cooling aids for front forks...? Next time I return from a ride I'll take some temperature reading using my infra red gun. Luckily I have crude damper rod forks so it's all a finger in the air compromise. It's a shame fork oil isn't manufactured to strict standards like ATF's....Dexron 3, spot on the spec' as Suzuki/Showa SS8 which is handy if you ride a Wee Strom DL650.....not recommended for the DL1000 which uses cartridges and needs fairy spit.

@CatalystReactionSBW

3 жыл бұрын

If you run forks on a dyno, oil temp can reach 100C hence flow rates being posted at 40 & 100C by manufacturers. MX bikes generally run much higher temps due to velocity/movement.

@richardrichard5409

3 жыл бұрын

@@CatalystReactionSBW many thanks for the prompt reply Dave, very interesting, take care and stay safe, Richard

@andrewstambaugh8030

Жыл бұрын

The reason for using 'fairy spit' ultra low viscosity fluids is they are more temperature stable than higher viscosities. If there weren't other effects in play, we'd be using water or alcohol for viscosity stability across a temperature range. Forks have more oil, and most commonly the load divided between 2 forks, and more surface area to providing cooling, so they get less hot than shocks. Differences in high flow vs high pressure style valves make a big difference in heat and wear... if being aggressively ridden. Daily commuting with an easy relaxed pace may not even warm forks above cold to the touch. Extreme MX can have a shock so hot that flash point is being considered...

Nice Vid as always! Thanks! I learn a lot from it! but what Fork oil do you think should I put to my Duke 200 Stock Forks? I use the bike for daily and sundays at twisties, aggresive riding also . I live in the Philippines which is have a mixed weather and temperature around 20C - 35C.

@kaiserdgreat

2 жыл бұрын

I also have the way to buy Maxima Fork oils.

@CatalystReactionSBW

2 жыл бұрын

@@kaiserdgreat I have not seen one in person. Depends on the odometer reading. If the forks are the same as the 390 base model, 15w oil works if you are over 70kgs, 10w if less than that. Maxima is great oil.

@kaiserdgreat

2 жыл бұрын

@@CatalystReactionSBW thank you so much Dave!

Motul 10W too hard action & less travel. Motul 7.5W too soft & over travel. Mix both 50/50 equals Motul 8.75W. Ureka I've done it. Good action & near max travel. May change to Maxima. 7

Thank you for your lecture. One question, is the higher viscosity oil create more bubble during aggressive riding, like track day?

@CatalystReactionSBW

8 ай бұрын

Thank you. Are you referring to air in the oil? Higher viscosity oil by default moves slower so the opportunity for air to be introduced to the oil is limited. Track days are generally easier on suspension as race tracks for the most part are significantly smoother than roads you ride on.

I like this video.

Thank you for sharing Dave, in my service book mention 20W for fork oil. I live in mix climate.. Lowest is 15 degree celcius and maximum is around 38 to 39 degree celcius.Is it still ok I use 20w? My small bike is Kawasaki Kaze / modenas kriss

@CatalystReactionSBW

2 жыл бұрын

Yes 20w with those temperatures (high/ow) is fine.

Dave, I am changing fork oil on an older yz. It calls for Yamaha 01. Would it be safe to replace it with Maxima 5w?

The base oil (base oil is the oil from the refinery without any additives) has a certain VI depending on type of base oil. Mineral base oil has usually a max. VI of 105. And a PAO synthetic (most common synthetic in automotive use) has a VI aprox. 130-160. This VI will not decrease due to shearing. So mineral oils has to be more additivated with VI improver to have a more consistent behavior in chocks. But VI will decrease due to searing over time. Synthetic oil needs non or less VI improver and thus better keep it's viscosity over time. PAO also have a better flow behavior.

@CatalystReactionSBW

7 ай бұрын

Great technical post and thank you for sharing your knowledge!

Have on RM 03 125 still not sure what to use any advise would be appreciated

Hi Dave. What would recomend for oem k7 gsxr forks? All weather riding, mostly short commutes but I like to have fun out in the lanes too. Your vids are great tools so thanks for your help.

@CatalystReactionSBW

Жыл бұрын

All weathers would generally suggest cooler climate overall with the exception of hot Summer days. My go to would be Maxima 7.5w and stock volume of oil.

@loftyintentions1985

Жыл бұрын

@@CatalystReactionSBW Cheers Dave. I don't think the oil has been changed once and I have the preload fully soft, despite being about 225-230 in full gear. If I stiffen preload it starts to feel like the front is on the head of a pin and very unstable. Could this be due to the oil being so high in viscosity, being so old? I was planning on changing the forks, with stiffer springs but I just don't have the funds right now.

Seriously, the manufacturers & fork oil companies do not provide guidelines as to which oil to use bc it's all relative, like Dave said, to how you're gonna use the bike. I had prior ordered Pro Honda/Showa SS-8 assuming it is most reliable for my CBR600RR.

I was at the track recently and under heavy braking only the front end would judder up and down in small movements. I'm unsure if i am expirenceign cavitation or maybe my discs are so slightly warped. The front wheel doesn't turn freely by hand but i put this down to filthy calipers because my bike is also my daily and the uk roads get rained on a lot so all that shit gets all over my bike every day.

@CatalystReactionSBW

3 жыл бұрын

Check the brake pads for angulated wear, then grab the forks by the bottom and see how much free play you have. Could be brakes, bushings or steering head, or a combination.

@Bikeadelic

3 жыл бұрын

@@CatalystReactionSBW thanks Dave 🙏💫

If Viscosity Index is important then Amsoil is better with 209 right

Hi Dave, if i recall you have a bandit 1250 as well. Would you recommend the RaceTech Gold Valves? I am a 150lb rider that uses the bike across a wide array of roads/styles. I currently have 1.1kg/mm fork springs and Redline 10wt oil. I have tried 1.0kg/mm springs but was unable to achieve proper sag without too much preload and a rough ride. The oil previously was too thick for the heavier springs and produced a harsh ride. Redline 10wt improved ride quality and I plan to try Redline 5wt then mix to a 7.5wt if needed. Handling seems great but I am picky and would like a bit more of a plush ride without costing performance.

@CatalystReactionSBW

2 жыл бұрын

Great R&D on oil. A tip of the hat to you. The issue with the forks is the compression pistons in that the valving is very soft hence going to strong springs with lighter oil as the optimal solution. Changing to RT Gold valves will help for sure as they come with a lot more compression valving and use 5w oil for more plush suspension action.

@e46silverbullet62

2 жыл бұрын

@@CatalystReactionSBW I appreciate the feedback! Will you be in the Northern California Bay area this riding season? I plan to hit the tracks after dialing in the suspension on the streets.

@CatalystReactionSBW

2 жыл бұрын

@@e46silverbullet62 Yes. Track schedule is here: davemosstuning.com/calendar/

Hello Dave . im not sure is rider sag ,static sag plus the sag when i sit on the bike or just the amount it sags under my weight ?. thanks Evan

@CatalystReactionSBW

3 жыл бұрын

Hi Evan. Static is the bike under its own weight. Rider sag is rider on the bike. Both are added together to create total sag.

Interesting , i heard you can use auto trans fluid in forks around a 7.5 weight

@CatalystReactionSBW

3 ай бұрын

There are many choicees but please Google an oil viscosity chart first to get your base VI and CsT numbers, then compare with the manufacturer's data if you are considering ATF etc.

Hi Dave, I live in Las Vegas. I have a 2022 Indian Scout Bobber. I will be installing a Legends AXEO fork suspension but I would like your recommendation of what Maxima fork oil weight to use?

@CatalystReactionSBW

3 ай бұрын

I would recommend the 7.5w oil given the heat of Vegas in the Summer.

Fjr 1300 rp13 15w perfecte voor zomer rijders

My 1984 vf750f Honda manual says to use ATF fluid. Is this just simply old technology and now I should use 10w or 15w

@CatalystReactionSBW

2 жыл бұрын

ATF is current use for today with your motorcycle , so use it :)

Those oingo boingos need lubricant to operate smoothly and the oil serves as resistance through the valves to slow down shock action. With out oil you are riding an expensive pogo stick. Too much and too thick it’s a lumber wagon with solid axles. Done correctly it’s smooth sailing with superb control.

Hey, can someone confirm this theory of mixing viscosity for once and for all? I grew up messing with mountain bike suspension (still do) and I still mess with vintage motorcycle suspension as well as high end stuff (rsv4), so I don't always have the option of adjustable valving, or I do an oil change thinking 10w would be enough only to find its still too thin. From what I remember, to get 12.5w, is it true that you need 3/4 of the volume to be 15w and 1/4 of the volume to be 10w? Or the other way around?

@CatalystReactionSBW

2 жыл бұрын

All the mathematics is here: advrider.com/f/threads/mixing-fork-oil-to-get-the-right-viscosity-howto.1454699/

@Rickie-37

2 жыл бұрын

@@CatalystReactionSBW Thanks Dave!!

@andrewstambaugh8030

Жыл бұрын

*It's a very close approximation to use a simple proportion equation.* And you should use cst or kinematic viscosity, not 'wt.' Pick the temp range you want (eg cst @ 40C) In decimal: [desired cst] = Pax[cstA] + (1-Pa)x[cstB] re-arranging that to solve for the P (the proportion): *Pa= (desiredcst - cstB)/(cstA - cstB)* multiply that by 100 if you want a percentage The proportion of B is just the remainder Pb= 1 - Pa, or in percents Pb% = 100% - Pa% Eg (should be using cst instead of 'wt'): Pa=(12.5-15)/(10-15) Pa=0.5 x100, if you prefer = 50% And since A is 50% B = 100%-50% so coincidentally B= 50% as well. Which makes sense, because the chosen 12.5cst is halfway between 10 and 15, so no surprise you need a half-and-half proportion to reach that. If you really care, you will do this and see what the combined effect is at other temperatures too, so you see what your new oil mix line will look like. *Unless you are an engineer designing something critically sensitive, you should never need to go deeper than simple proportions within the same oil series for determining your mixtures.* Note: *if your desiredcst is outside the range capable with your mixes, instead of a decimal number, you will get a number greater than one or a negative number, which are non-sensical as a proportion of a whole.* e.g. 45cst: In reality, what does it mean to add -6 of A? And B being added at 7x the total mix volume? Are we distilling -600%A out of 700% B to end up with 100%? Non-sense for our purposes. Tiny note, maybe ignore this because you don't need to know it: the mix may not wear evenly with time, so expect a manufacturer created oil to have the most long term stability, but this effect is still likely to be small/insignificant if you've chosen use-stable oils.

Read the "Forking" manual?

Hello Dave. I have a Suzuki VZ800 year 1998. I live in Portugal (minimum temperature 12ºC and maximum temperatures sometimes reach 40ºC). What is the best fork oil to use? 15w ? Thanks

@CatalystReactionSBW

Жыл бұрын

Hi Ricardo. Thank you for your question. 15 or 290w based on your weight and duration of rides (heavier weight if you ride for 1-3 hours at a time at speed vs short urban rides).

The oem Yamaha 01 fork oil for the mt10 seems to have to same numbers as the motul and maxima 5w , should I stick with that weight when changing do you think , spirited riding two's up on weekends , or shall I go slightly higher in numbers there for needing less preload and more range , I didn't think it would be this hard choosing a fork oil 😁

@CatalystReactionSBW

7 ай бұрын

If you are in a generally cold climate, Y01 oil makes sense. If hotter overall in the 30C range a lot of the time, Maxima/Motul makes more sense

@bccapone837

7 ай бұрын

@@CatalystReactionSBWmuch appreciated I'll stick to something very close to those viscosity numbers then , just another quick question as I don't fully understsnd the mt10 service manual fork oil level , does it mean 114mm air gap from top of the oil to the top of the fork tube with the spring out if I'm doing seals and if just changing the oil can i just do what you have done on the dump and run when you measure the amount poured out and match that back in again , thanks again for the helpful videos

@CatalystReactionSBW

7 ай бұрын

@@bccapone837 You can do the dump and run but draining will take a while so be patient. Same goes with fresh oil going in. Takes time. Noted on the UK and yes, lighter oil makes sense.

@bccapone837

7 ай бұрын

@@CatalystReactionSBW much appreciated thank you

Is it wrong to use 10w40 engine oil in Chinese forks? Thinking about application and market. Most of these bikes are for far east sale so the small numbers sold here in the west is mhhh to the manufacturer. Accessablity of exotic oil for forks in these regions and the means to purchase, meaning we in the west are blessed to afford such things. 10w40 engine oil in Chinese 125 forks right or wrong?

@CatalystReactionSBW

3 жыл бұрын

Most will use ATF for fork fluid, not engine oil.

I have a 2014 Triumph Tiger ABS, not the XC or any more off-road version. I just purchased the bike a few months ago with about 7800 miles on it. The local service guy says the bike is designed for lighter riders, I'm about 225-230 pounds. He said I should think about changing to higher W oil and maybe different springs. According to Haynes manual the fork is: Showa 43 mm upside-down cartridge forks, non-adjustable. Any suggestions to improve my ride for 85 road - 15 trail, pretty non-aggressive rider.

@CatalystReactionSBW

Жыл бұрын

I would suggest 15w oil and 50ml more than the manual suggests for volume. Thus will be a dump and run project for you! kzread.info/dash/bejne/h6N9s7CcqNTHg6Q.html

@griffshark

Жыл бұрын

@@CatalystReactionSBW Thanks so much for your reply and great videos!!

Hi whant to no can i put a stronger rear shock on my xr honda ct 190 this one is to soft and can i put on my front fork tronger oil 20w my weight is 85 kg on the bike i use my bike on the farm

@CatalystReactionSBW

8 ай бұрын

www.tapatalk.com/groups/hondatrailcts/rear-shock-upgrade-for-ct90-t7968-s10.html

Installed Hyperpro springs, with included Hyperpro oil 10W. Standard damping rod forks, freshly rebuilt. Too harsh on sharp bumps, rebound too slow when fully out, almost 20 mm of stiction. Twice tried loosening axle, lower tripple clamps, steering stem nut, bounce the forks to allign everything and torque everything down. Nothing. Decided to dump the Hyperpro oil and put in Motul 10W. Faster rebound, not too fast, down to 10 mm of stiction, and smoother over sharp bumps. Why would they not standardise fork oils? And why so much friction with Hyperpro 10W?

@CatalystReactionSBW

3 жыл бұрын

I would respectfully suggest that there is no grease in the grease groove of the oil seal. kzread.info/dash/bejne/o39qwZmohKnFkqw.html

@CatalystReactionSBW

3 жыл бұрын

In regards to standardization of suspension oils - none of us have any idea why but as they say, it is what it is" and we find our way through it.

@KarloZg9000

3 жыл бұрын

@@CatalystReactionSBW Thank you for the response, and everything you do to share your knowledge. It means a lot to us DIYers on a low budget. It was greased when installed, I even tried "forcing" some grease by greasing the stanchion and rapidly compressing it, after it didn't help I tried doing the same with silicone spray. Is there any chance that Hyperpro oil is just subpar? I doubt a company would deliberately sabotage themselves with bad oil.

@KarloZg9000

3 жыл бұрын

@@CatalystReactionSBW That is the exact video _I referred to when trying to fix the problem.

@johnpublic168

3 жыл бұрын

@@KarloZg9000 as usual you covered it perfectly . Ideally one picks a 0 or 2.5 weight oil for the least temp effect. And valve and piston design for that bike using the least weight. I found your reasoning for no mechanical changes to be excellent. We use belray. Because we are to cheap to buy 55 gallon drum of koni 0 weight which is the only way they sell it. And the only source I know of.

I have OEM 10w oil and the bike seems harsh/rigid over speed bumps but dives really deep during braking, or if I squish it from still. It's a upsidedown type and do to a leak situation, i have to refill/replace, so i would like to improve if possible.. What kind of oil should I buy and use?

@CatalystReactionSBW

2 жыл бұрын

Maxima or Motul 15w based on your description.

@andrewstambaugh8030

Жыл бұрын

@@CatalystReactionSBW Quick theory question: If addressing something like that with valving, what speed ranges would you consider those 2 conditions (speed bump harsh, vs deep braking dive)? ultra low speed low speed med (braking dive?) high (speed bump?)

@CatalystReactionSBW

Жыл бұрын

@@andrewstambaugh8030 High speed is pot hole etc as it is massive sudden velocity immediately introduced to the suspension. Brake pressure is not immediate and violent, therefore medium speed as per your table of data points.

what u recomend for speed four triumph??.. i ride it in hotter climate, from 17 Celsius to 35 Celsius... i dont comute with it often.. i ride it more on weekends on highway and mountain roads..tnx

@CatalystReactionSBW

3 жыл бұрын

The Speed4 stock forks respond really well to 15w oil with that climate.

@chevchelios7342

3 жыл бұрын

@@CatalystReactionSBW ok..is motul 15w ok or should i try finding maxima 15w?

@CatalystReactionSBW

3 жыл бұрын

@@chevchelios7342 either of those two if available or if not Motorex

@chevchelios7342

3 жыл бұрын

@@CatalystReactionSBW we have motul and motorex were i live.. i think that every motul product is overprized in my country...i use motorex oil in my bikes, so ill try the fork oil than... tnx a lot man.. ur advise meens a lot.. ur the best

What are your thoughts on mineral fork oil... Does it do any damage on a heavy cruiser... I ordered 20w online and didn't realise until I put it in my forks that it's a mineral oil

@CatalystReactionSBW

11 ай бұрын

Mineral oil will not damage your fork internals. There are rubber o-rings and teflon bands inside the cartridge if you have that system. If you have a damper rod, that is simply metal. All good!

@dozer3955

11 ай бұрын

@@CatalystReactionSBW ... Thanks buddy

9:46 It's not 40cSt and 100cSt. It's the cSt numbers at 40 and 100 degrees Celsius. 1cSt = 1mm^2/s.

I know this video is over a year old but I’m just now seeing it. My question is how much does rider weight play into the fork oil choice?

@CatalystReactionSBW

2 жыл бұрын

If you change springs due to rider weight, then it comes into play. Oil viscosity relates to spring tension = rebound velocity.

@jamesbastiaanse6877

2 жыл бұрын

@@CatalystReactionSBW thank you for the reply. I only weigh 150lbs so all bikes are oversprung for me.

@CatalystReactionSBW

2 жыл бұрын

@@jamesbastiaanse6877 Not all but the majority especially at 600cc and above categories.

Dave, Dose the weight of the rider play a part in all of this?

@CatalystReactionSBW

3 жыл бұрын

Weight and ability combined, yes. Another factor is climate - Iceland is very different to Africa so oil viscosity is very important in that way too.

So at 2:08 you say weights or winters. When you say weights is that just a generalization because so many people call it that already so no going back? Grammatically does the W only mean Winter and people just say weight by mistake?

@CatalystReactionSBW

2 жыл бұрын

90% of people know weight. the remaining 10% know Winter as they have studied oil in depth especially for VI and cSt. So I use both terms to initiate a conversation of "Why did he say Winter? Huh?" and hopefully have someone Google this topic.

FML! why does Ohlins FSK104 cartridge kit tell you to use 40w? Ohlins Oil product reference #20. Wow, this can't be right can it?

does fork oil go bad, unused of course? in other words: how long is the shelf life, stored in a cool dry environment?

@CatalystReactionSBW

2 жыл бұрын

If the container is sealed, I would use it 3 years later.

@gabe1392

2 жыл бұрын

@@CatalystReactionSBW thank you for the quick reply. looks like i have to make a trip to the motorcycle store.

I'm a layperson, but in layman's terms I've heard that independent of cSt, a higher Viscosity Index oil potentially has greater stiction and isn't as slippery. A super high VI oil may be needed for a shock that can get quite hot, but for a fork, too high of a VI may be detrimental. Is that a linear relationship? Is a higher VI oil always 'stickier' than a lower VI oil, or is it not that simple? Can anyone elaborate?

@CatalystReactionSBW

2 жыл бұрын

That is correct and well stated. There is no linear relationship de to various engineering solutions created in each fork from different manufacturers. In the case of Ninja 400 forks with no adjustments, VI ensures that rebound is correct for a given period of time, then it must be replaced when rebound is too fast from broken down oil. With cartridges, most are engineered today for 2.5 or 5w, but internal engineering with valving allows for some flexibility with VI based on regional temps eg Death Valley to Vancouver BC. Hope this helps.

@carpetbombing4233

2 жыл бұрын

@@CatalystReactionSBW Thanks for taking the time to reply. When I got started down this rabbit hole of understanding suspension oils better, I presumed you wanted the highest VI you could get your hands on regardless of application. I guess I know better now. This is all interesting stuff. In a 2019 WR250F (cartridge forks) I'm about to switch from 15.6 cSt OEM fork oil to 18.9. I'm a 240 lb rider. Do you think I'll feel a difference beyond what I can adjust with damping clicks? OK to go thicker?

@CatalystReactionSBW

2 жыл бұрын

@@carpetbombing4233 go to 22-24cSt for the WR forks :)

ufff my head is spinning lol Lucky me, I do not have a ridding ability... a stock iron horse suffices lol

Almost too much info for a noob to process. What gets me is why doesn't any OEM make drainable suspensions? We change our oil, we change brake fluid and radiator fluid...why not shock oil? Seems like this is left out and 3rd parties and dealers rake you over the coals for this type if work. For me, I believe I would benifit from a simple change in fork oil and keep the OEM suspension. Not happening without a major teardown of my Z900. Give us a way to drain and change this and save the teardown expense for overhaul time.

@CatalystReactionSBW

3 жыл бұрын

They used to provide a drain bolt at the base of each telescopic fork leg on the outside that had a copper washer to seal against the machined surface. Then someone created a legal fuss as they did not tighten it so the bolt went away. With the introduction of upside down forks, it is impossibly expensive to provide an external drain bolt.

It's actually maple sap at the tree.😏

Is fork oil just hydraulic fluid, except for the bigger price?

@kariholma3850

3 жыл бұрын

Looking at cSt numbers, 10W seems to correspond ISO VG 32 hydraulic oil, 15W ISO VG 46 oil and 20W ISO VG 68 oil

@Leon-fz5gm

3 жыл бұрын

@@kariholma3850 They should have different additives as they both have different purposes. That being said, I am sure some fork oils are just branded hydraulic oils. I would like to hear details from people i the know. Personally I use hydraulic oil in my bike's forks. They work well for me. I am not racing though. The advantages of hydraulic oils are that the data is easy to find and there is a lot less hype and marketing involved so they are cheap enough to be able to optimise your fork's behaviour through trial and error, reaching your preferred viscosity even if that means mixing two standard viscosities:-)

This is like using Yellow Card reporting to make a life critical decision about your health. Thank you for sharing this Dave. After watching a few time I expect I will be able to make better decisions.