On my heads, I tend to remove a lot more material blending the short side radius. I also remove material from the walls of the runner to try and blend and smooth the transition from the bowl to the runner.

Still educating to this day, i used your video as a guide to do my yx160 head and it worked out great! thanks

Great video! One the best I’ve seen regarding porting! Very clearly captured and explained! Thank you!

this is the best video about the subject on YT. THanks

Great video! Awesome fundamentals

I appreciate your time. I'm gonna give it a go! Very well explained...best I've seen!

Great video. Thank you for explaining it properly for use .

Another awesome vid. Thanks!

@KartFab

6 жыл бұрын

No problem. Glad to help!

what a simple and exactly accurate what and why porting the head.

Simple explanation of a stage one porting well done sir thanks for sharing

@VeritasEtAequitas

4 жыл бұрын

"stage" lol. Engine work isn't rated in "stages" except video games and marketing gimmicks.

@throwawaypt2throwawaypt2-xp8nx

Күн бұрын

​@@VeritasEtAequitaswell clearly there are stage 1,2,3, and 4 kits for predator 212, are those kits fake?

@VeritasEtAequitas

Күн бұрын

@@throwawaypt2throwawaypt2-xp8nx Congratulations, you've discovered that people will market things simplistically to consumers. Who ever could have imagined such a thing? No, stages are not a standard anywhere. They're arbitrary. You port for the balance of volume and velocity for your particular application, which depends on where you want to shift the powerband and what type of induction you're using, and its flow characteristics as well

@throwawaypt2throwawaypt2-xp8nx

Күн бұрын

@@VeritasEtAequitas obviously it's arbitrary but it has to be categorized somehow, what about for cars? audis have stage 1 ecu mapping, what u say to that. lol the phone u typed this out on for example the iPhone 13, number 13 is a "marketing ploy" arbitrary number too

@VeritasEtAequitas

Күн бұрын

@@throwawaypt2throwawaypt2-xp8nx Like I said, marketing. No, it doesn't have to be "classified somehow" lol. Just quit. It was funny, but now it's just disappointing that you're serious.

thank you, informative !

@KartFab

4 жыл бұрын

You're welcome!

Thanks

love it

Very helpful, me thanks you

informative

Good stuff. You did a nice port job, that looked really good. Yes, be very careful to not knick the seats or you will need to get them cut again at a machine shop. Sometimes if I feel nervous about that happening , I’ll put some thin strips of tape over them. It can be fussy to apply though. It doesn’t add a lot of protection from causing a knick, but it makes you aware of them. If you’ve got your head off for work, clean up that casting flash in the ports. it’s not much more work.

@KartFab

6 жыл бұрын

Yeah I really like the smaller flexible attachment on my dremel so I can even rest my fingers on the seat while working on the portwork. Once you knock the seat it could be game over for the head!

@MrTheHillfolk

6 жыл бұрын

KartFab Yup steady is the game. I got a dremel with the “speedo cable” and it’s so handy for this work. I usually hang it from the ceiling over the bench so it’s easier to manage. Set up a comfortable work area and go to town. Hey i know it’s usually kids and inexperienced folks attempting this, with limited money but if you can try to round up a junk broken head. practice on that and knick all the seats you want until practice makes perfect 👌🏻

Great

On my riding mower with a 13.5HP Briggs, I opened up where the air comes into the filter and made the path to the head as streamline as I could. Smoothed (just broke) the sharp edges where the ports transition into the bowl on both the intake and exhaust side. Also done a half shaft mod to the throttle and choke shafts in the carb. On the intake side. The intake itself has a gasket, lip, then the port. The lip made a dark ring and the gasket made a slightly shinny mark on the head. So I opened up the intake port of the head till there was only 1/4th left of the dark colored ring. Going no more than 50% into the port towards the bowl and blended it to the OEM sized port. I didn't do a whole lot on the exhaust side. The exhaust manifold port was much smaller than the port on the head and I wanted to open the exhaust manifold up till it was slightly bigger than the port on the head. Unfortunately, there wasn't enough metal. But I was able to get the exhaust port and manifold port to the same size. I originally had a 1.2 ratio rocker on the exhaust and a 1.88 ratio rocker on the intake. Measured and remeasured to confirm the ratios. They are correct. I swap them around. With all that was done and a spark plug opened up to.042in with the ground strap cut back, I've noticed the following. More power in the mid range to upper RPM's with no ill effect in the low RPM's. Throttle response is also much better now too. It needs a rejet since it runs rich at any RPM above idle. But I'm happy with the gains made with the governor still on. I'd be lying if I said it didn't feel like I got 3 or 4HP gain.

@jamesstoy8967

2 жыл бұрын

It's been my experimental engine. I've tried out several combination's so far and this has been my favorite one so far. Now I'm wondering how would it respond with a slight increase of lift on both the exhaust and intake valve and add a little more duration to the intake and a small bit to the exhaust side. Keeping the valves opening and closing events as OEM. Plan to swap the 1.2 ratio rocker for a 1.5 when I find one.

@A_Stereotypical_Heretic

Жыл бұрын

There's a reason your exhaust manifold is smaller than the exhaust port on the head...there's a reason for every design detail on your engine. Porting is a massive waste of time and a big risk on a tiny 4 stroke engine.

@jamesstoy8967

Жыл бұрын

@@A_Stereotypical_Heretic You just stay away from them then. Folks have been porting small 4 stroke (L and OHV) engines for YEARS and winning races with such engines and proven time and time again that it works. And having an exhaust manifold smaller than the exhaust ports of the head is NEVER a good thing on ANY 4 strokes no matter how small or large the engine is. It causes turbulence and makes for a non smooth path for the exhaust gases to freely exit causing improper cylinder clearing. You actually want the manifold primary pipe the be about .150 thousandths larger than the exhaust ports of the head. This will give the exhaust gases a smoother path to exit quicker clearing the cylinder more effectively plus the lip created helps reduce some of the reversion that happen to give the engine cleaner fresh charges in the cylinder.

@A_Stereotypical_Heretic

Жыл бұрын

@@jamesstoy8967 actually no, no one has ever won a race due to porting. Matter of fact they almost always cast with the port sizes they require for what they're looking for. The so called gains from doing this are so negligible that the risk of ruining your engine far outweighs the tiny fraction of performance increase you MAY see...but likely won't.

@jamesstoy8967

Жыл бұрын

@@A_Stereotypical_Heretic believe what you will. You wouldn't see the truth for nothing.

Terimakasih master enjin

Good info Grant!

@KartFab

5 жыл бұрын

Thanks. I stole it from Jody at ARC haha! Just a mild port job.

The only thing i might add is port matching the intake manifold /head connection and head / exhaust pipe connection.

Thanks for another informative video,still waiting for parts on my baja heat so i can put together a torque converter/jackshaft set up, did you have any trouble with the back wheel moving with the tensioner, mine was stripped on the brake side... I had it all tight so i thought, i will get new one if they will hold up ok

@KartFab

6 жыл бұрын

You need to torque the rear axle to spec. Chinese bikes are of questionable quality but it shouldn’t strip if you had it all torqued properly.

You look high lol, nice video

@KartFab

6 жыл бұрын

IM HIGH ON LIFE MAYUNNN!!!!

@wristtwistsanbongrips7563

3 жыл бұрын

Totally baked

You need to do a better job on the intake's short turn radius.

That area your porting would be the mca. It should be at least .85 of the throat😎

I have a Cam in my mini bike now with 265 lift and 236 duration. It's an aggressive cam and i just paid like $125 bucks on Ebay for a Ported head that comes with the valve assembly and 22 lb springs and it's supposed to go very well with an aggressive cam that has 265 lift or more. I also ordered a bored out carb to go with them as well. I'm really hoping when i get all this put in my bike i notice a nice difference in power and performance but we shall see. It's only a 196cc engine so i dunno how much more power it can possibly produce but should be somewhat better. I've done all the usual mods to it already and as of now it goes around 45 mph. I'm hoping that after the stuff i ordered is installed it will go over 50 atleast. 🤞🚲

@KartFab

2 жыл бұрын

You can easily triple your horsepower with cam head and carb

@litnlarry

Жыл бұрын

How was your 196 build? I’m currently building a 196

@A_Stereotypical_Heretic

Жыл бұрын

@@litnlarry apparently not what he was hoping...

Do I have to get a larger carburetor and less restrictive exhaust to get perf. gains?

@KartFab

3 жыл бұрын

You get gains with different combinations. Carburetor is very restrictive, so you will see good gains with that.

On thing you can do to increase power is to port and polish your oil return galleries as well as pressure galleries because those casting imperfections will decrease the oil flow with ultimately translates to power loss.

@KartFab

6 жыл бұрын

Ehh nope. Not on these small engines. Galleries eh? 👀

@mikeshestopal5644

6 жыл бұрын

KartFab oil return ports on the cylinder head

@KartFab

6 жыл бұрын

I see no benefit to that. What we are talking about is a simple splash lubricated small engine. These engines have two holes in the head that communicate with the short-block. The hole between the lifters and the hole on the intake side. These holes allow oil to splash up into the head and drain from the head, as well as allow air (blowby) to pass into the valvespace, and ultimately through the valve cover vent. The only thing that matters here in the engine oil wise, is that you have enough of it in the engine. There is no power loss or gain to be found by what you are stating. In some higher HP applications, you can see an RPM increase by tapping the crankcase cover or block and routing some hose to the valve cover, allowing more airflow (from blowby and the movement of the rotating assembly) between the short-block and the valve-cover.

@the_mad_ratter

5 жыл бұрын

If you wanted to speed up oil flow around the top end, you could use a thinner (lower viscosity) oil which would have less trouble making its way around the engine. It'd also reduce drag on internal moving parts (ie, the bits that have to push through oil to do their job) which = more gains. I don't recommend doing either on a small engine like this lol

I got a few lawn mowers, ready to do some port work on them and see how it goes...

@ford200555

5 жыл бұрын

Did some port work to my weed wacker, things rips

@austindeems5406

5 жыл бұрын

@@ford200555 ?-? But two strokes don't have valves.

@ford200555

5 жыл бұрын

@@austindeems5406 mine does

@bucknut2850

3 жыл бұрын

@@austindeems5406 hahaahahahahaha wrong

Good day kart fab where can I buy racing heads for 18hp block, thank you.

@KartFab

4 жыл бұрын

You’ll have to be more specific

What are the name of tools that u are use in porting?

@SiriusC1024

5 жыл бұрын

1/8 inch shank carbide burr bits.

Polishing the exhaust is a good idea, but polishing your intake is not, keep it rough.

@the_mad_ratter

5 жыл бұрын

Yup, nice and rough to induce swirling, and reduce the chances of fuel vapour condensing back into liquid fuel on the smooth surfaces. Glad someone put it, I came down to the comment section to say the same :P (even though both of us are ignoring the fact that this is porting, not port polishing. Another place I found needed serious work on one of my engines was the inlet 'manifold' where it met the intake and the carb - it was massively misaligned and needed a fair amount of material taking away.

@brianciszewski6417

4 жыл бұрын

Don't smooth it but don't keep it really rough. Leave it medium

@JustKevinnn

3 жыл бұрын

@@brianciszewski6417 So when porting only smoothen the sharp edges and that's it? Or does it need to be roughend after with sandpaper?

@A_Stereotypical_Heretic

Жыл бұрын

@@JustKevinnn just don't polish it. After your last sandpaper weight let it be.

@JustKevinnn

Жыл бұрын

@@A_Stereotypical_Heretic your message came a bit to late, i did port it, and didn't polish it, the engine worked perfectly is was very fast sonit definitely worked, but after half a year it got tired, so now i have a yx160

Interesting...

@KartFab

6 жыл бұрын

You’re alive!

@mtnsleder2829

6 жыл бұрын

You thought I died? Ha ya DIY hates me...

can you reuse the head gasket if the engine has never been ran before and no heat has ever been built up?

@KartFab

4 жыл бұрын

if it is a steel ring style gasket, you can probably reuse. It is best practice to use a new one as you torque the head down the gasket will have a certain amount of "crush" to it when it forms to the head.

@ezraconner875

4 жыл бұрын

@@KartFab okay thank you

@markebedwell6646

2 жыл бұрын

You can reuse any gasket if does not stick and tear, all you do when torquing is remove crush height and I did go to mechanicing school.

why is there no throat? now i want to remove mine

Do u need to upgrade your valve springs wene you port and /or polish ?

@benzinz_4821

3 жыл бұрын

No. Unless you are putting a bigger camshaft with higher lift or duration.

I think I asked you already but can you do CG 250 engine

@redneckasmr-xd1gg

3 жыл бұрын

ya i had a cg150 i ported it the 30mm carb and an exaust ran a lot better. but the cam is small but i did find a upgrade cam a while back on ebay

@stoosee

Жыл бұрын

@@redneckasmr-xd1gg what is your port diameter in intake and exhaust?

I read that grinding the intake side reduces low end torque

@KartFab

Жыл бұрын

Nah, grinding it WRONG will do that.

wait has anyone done this to a 142f for a bike

Very good video, but... That only covers OHV. I am in the process of doing a "Stage 1" (Homemade Exhaust Headers) on my 1991? Kohler Magnum MV18 (Vertical Shaft) Engine. Model#MV18S Spec#58560 . Is this engine even "Port-able"? There are no casting "reminents" or intrusions in either the Intake, or Exhaust Ports... I have been "suggested" to Upgrade to a Larger Intake Valve (1.500"), but the Stock one is 1.373", and I really don't know what to do, or what expensive Tools I need to aquire (for a One-Time job)... I hope I'm not "overwhelming" you with questions, but I can't get a Straight Answer from anyone. Feel free to Message/PM me if that would be more efficient. Or pass me to someone who KNOWS Kohler Magnum Opposed Twin Engines if you can. Thanks for the Awesome Education!, -Thomas (12) Port Orchard, Washington

@KartFab

5 жыл бұрын

The three things that make power on an engine are the camshaft carburetor and cylinder head. Call of the folks over at performance 670.com. Even though this is a different business they can connect you with the people that work on the Kohler engines to make insane horsepower. In my experience multi angle valve job porting milling cylinder heads camshaft jetting etc. should all be done by professionals,

@tkskagen

5 жыл бұрын

@@KartFab Thank you, will contact them tomorrow!

its wonderful. i port every small motor i get for even miniscule gains from the losses cuz of high altitude/less O2 in the air= less power. 3.5% loss of power for each 1000' in elevation? 1% loss in power for each 10*F over 60*F so i am already behind at 3000'... 13%? runs RICH with stock jet= BLACK spark plugs from soot of too much gas. they make BIGGER jets, generally NOT smaller jets for high altitudes/less O2

@briantayes2418

Жыл бұрын

Insert a copper wire, that will reduce the area of the jet. Calculate the area of the jet and of the size you want it to be and find a copper wire that equals the difference in area. Or you can solder up the jet and drill it out to the desired size. Amazon has metric and Imperial mini drills that are great for this. I hope this helps.

@KartFab

Жыл бұрын

Opposite is true. Smaller jets for higher elevation.

Sou ds grt ,,but u missed .ost important part 2 do most of all

I’ve seen some idiots hogging out the exhaust ports 😳 don’t! They don’t seal to the exhaust gasket

I start hacking at my ports with a die grinder until the ports are as big as possible = 30 hp

@syndakitpanda1777

3 жыл бұрын

Is it naturally aspirated ?

I have bob Ross vibes~

High percentage of ignorant comments here. Lol!

cubic feet XD

Soooo...no gains?

@KartFab

Жыл бұрын

27% increase with intake/exhaust

@A_Stereotypical_Heretic

Жыл бұрын

@@KartFab 27% increase in what?

Ok..them lil shite engines....they got sum pep in they step...so....lets say...we do this to a ....Ughhh...250cc with 17lbs torque and 12hp....what's the % in Gains?

@KartFab

5 жыл бұрын

About 7% gain if you do nothing else. Porting is usually done in combination with a better cam and carb for the best performance. For example I have an engine that went from 10 ft lbs of torque to ~14 and 6.5hp to 17.5hp with ported head, 12.1:1 compression, slide carb, cam, and rebore from 212cc to 220cc

@trucker2b

5 жыл бұрын

@@KartFab that's were I'm aiming...the only part that's hard to mod is the cam...since its a 250 and its a China import its hard to find and replace with performance parts

Bro don did it

Don't need u porting nothing of mine,,o,, boy find flow bench,u,ll learn quick ,what a difference, u need 2 do!!!!

bro why? take it to a machine shop

@harisyoung4110

5 жыл бұрын

so what he gonna do with his all of the rotating bit and kit if he just sent it to machine shop ?.... the tungsten bit its not cheap to buy bro,

@Louis-op4zj

4 жыл бұрын

@@harisyoung4110 he said the bits were 12 bucks

@Louis-op4zj

4 жыл бұрын

Run what ya brung, build it, love it. Rip and replace and pay to play are all too common bro, as my old man always says, get amongst it.

@harisyoung4110

4 жыл бұрын

@@Louis-op4zj yea exactly man...im also all built it my self... i feel more perfection on doing it myself rather than asking machine shop do it... it not about money at all, it about pleasure... cheer mates

@Louis-op4zj

4 жыл бұрын

@@harisyoung4110 love ya work bro. Ever in oz send me a msg