Funny, I've been putting off making a video on base plate motors. Might get back on that since they're somewhat common. It could mean a few things depending on the size of the base plate. If the plate is around 5mm plate like mine, then it means you're running an early style piston with the late style crank so you can use standard .120 over bore pistons that the early ones were allowed to have. If it's a thinner plate, then it could be a stroker crank or even the YZ250 piston.

Nice video. Glad you're putting this kind of info out in vid instead of text on a forum.

Hell yea, that was a great video. 5 stars. I have a 250R jugg that I didn't know what model\year it came from. With the help of your video, it appears that I have a stock ported '85 ATC250R jugg.

Im new to the sport Im glad you have your video clips out there, they are very helpful keep up the good work rusty

@jaxonkainan Glad you found it useful! Tough to say what the issue is over the internet. Assuming you have the correct piston (early piston with a late rod spacer plate motor) the place I'd start looking is the compression; Make sure you still have the compression you're expecting.

excellent video Rusty, very very helpful

@slrrman88 You can, I've done it, but you have to be wary that if you out a lot of time on the piston, you run the chance of the sleeve becoming lodged in the intake and making an expensive mess. When I did it I was at the peak of my racing involvement, and was putting fresh pistons in my motor two or three times a year, so this wasn't an issue. I also converted to the base plate motor soon after.

Great Video again Marc. I'm sure that these videos that you are making will help all those two stroke Newbies understand the venerable TRX better. Only thing, you failed to mention that your "porter" warned you up front about the early model cylinder and its tendency to break at the rear studs when ported. :^o You might want to show at least a pic of how Pro-X reenforced that area, as well as how Duncan made the rear stud holes taller, requiring a longer base stud. Just an idea.

3:53.They are this way so when its at bottom dead center,the rings dont fall into port.One side is lower than the other.

I think it's best to user a spacer and early piston with the early cylinder. It's possible to use the late model piston on the long rod without a spacer plate. I ran this setup once. I found, however, the skirt of the late piston wore faster against the open intake of the early cylinder. Fortunately I raced at the time, so the piston got changed regularly, but there's a chance that, over time, the late piston could wear enough to lodge itself in the intake of the early cylinder.

LMAO!!! Yep, you nailed it and I didn't check out the "more info" area. That's too darn funny---you know me all too well. For anyone that is a bit confused by this short discussion, I am know as "mindcrime" on most of the Quad/Two Stroke forums, and do primarily MX/Woods porting. With that noted, Marc, I'll let ya slide here. ;^D

Lol! See the More Info section. Actually, I briefly covered it at 4:18 - Yeah, I accidentally said "I did it". My Duncan is out, otherwise I was planning on talking about that.

you can also tell by where the coolant line hooks up. Theres a kind of flat circle on the trxs where the atc's has a very small one

I have an old Hot Rods crank and it has KC 109 on the side of the rod as well, so I'd suspect it's a stock stroke long rod crank. However, you might want to check with Wiseco (I THINK they make Hot Rods) and make sure because I know they offer a 4mm stroker crank.

Not sure about an Odyssey cylinder, but I've seen Pilot, Polaris Sport 400, and Rotax cylinders on TRX bottom ends. The closest fitting I think is the Polaris and the kits are called "Polandas". There was a Polanda motor for sale on atvriders just this past week, actually.

sir how many degrees will it be in the intake and commune lines of the original?

@TheCorbin315 OEM Honda gears or the Yukon kits?

Do the bridges crack at all in rhe old jugs?

if you do put an 85 cylinder on a long rod engine you do have to put a spacer right?

could you run a 87-89 piston with a 85-96 cylinder on a long rod motor

Well, I don't have anything to weld aluminum with, or a mill, so it'd be $80/hour for me. But the Duncan jug works really well for what I do.

The problem with welding a cast aluminum cylinder is it tends to warp a lot when you start running. Plus, if you're going to go through the hassle and cost of relocating cylinder studs, you might as well just graft a larger cylinder on it.

Good Video Sir

I have a question about a few things in this video ( I know it’s an old video) is there anyway I could talk to you about a few questions on my 250r

@rustyATV im not sure. im assuming aftermarket

@rustyATV My cylinder compression is 200psi, what kind of gas can i run? can i run 50\50 race gas? 100 ocatane un-leaded? or 93 octane pump gas?

my crankshaft is a hot rod brand. it says kc 109 on one side of the rod. i tried to find out if it was stroker or just a regular long rod and had no luck. thought maybe you could help me! thanks

Ive got a lt250r and im wondering which motor is "better". The lt or the trx?

Oh, a resleeve? Don't know how big you can go doing that. LRD used to had a 300 re-sleeve kit that Bill Ballance used to use back in the day. Don't know details about the Polanda, other than the cylinder stud holes are pretty close. Go to the forum on atvriders and search for the thread "440 polonda MX part out" in the 250R sub-forum.

Hey they still make the gears for the 250r. You have to buy them from esr

How to order piston and piston ring of trx250

Im not talking about using the odyssey cylinder just a odyssey fl350 sleeve and boring an 85-86 atc/trx cylinder to accept the odyssey sleeve and using an odyssey piston and a spacer plate on my long rod 87 motor think it will work? would kind of like to stay all honda. what configuration are guys using the pilot 400 cylinders in long rod or short? My brother has one of those damn KTM powered outlaws and want to shut him up lol

@250rsrcool Not being able to see either quad, I guess it depends on what you're looking for. If you're looking to own a 250R, then maybe, but if you're looking for a quad to race other quads, keep in mind that some critical engine parts in the 250R are not available from Honda anymore. Part of the reason I got a dirt bike is because I've retired my 250R from racing and regular riding on account I can't replace the transmission gears.

@dakotaboughman3195

6 жыл бұрын

rustyATV awsome videos Rusty! I know its been years since youve posted this. But the company Yukon Gears makes transmission gear sets for the R. As far as forks and drums go, idk.

No. Did he get the cylinder bored to match the piston, or did he just put a new piston in it?

You sure about that? My Hot Rods crank is a stock stroke long rod replacement. Got it back in '06 and stopped using it because the fit in the mains was horrendous. Also, Wiseco's site advertises a 72mm stroke crank, which is the 250R's stock stroke. Refresh my memory on the port setups. Actually, you may want to hit up DeoVindice who posted below; he set up both of my OEM jugs.

Thanks! Yeah, I always thought visual aids were better than text for ADD people like me.

Yeah +1 to what KSRRider and Adam said.

@250rsrcool I really don't know anything about Janson or specific tuners. Have you tried asking on the forums? Atvriders(dot)com has a very active 250R forum with people who are rather knowledgeable about aftermarket items for the R. They would be a much better source for that kind of stuff than me.

@250rsrcool! Sorry! I really couldn't say! So many variables.

Hey has anyone put a odyssey fl 350 sleeve in a atc cylinder? I know its air cooled but that shouldn't matter ports look the same and 80mm bore and 72mm stroke of a long rod engine hmmm thats just short of a 370 kit and with the over size 82mm piston thats 380cc oh and of coarse you'd have to run a 5mm spacer for the diffrence in the early model cylinder and long rod configuration.

I have a stock 1985 and a stock 1986 and stock 1989

Is the trx bottom end different in any way from an atc bottom. ? Love your videos 👍 from a 250 r fan in northern Ireland

@rustyATV

4 жыл бұрын

Depends on the year you're talking about. The 1985+ ATC's have the same engine as the TRX and there are minor differences between the bottom ends. Gear ratios in the trans are the biggest. The 1984 and earlier ATC's are air cooled and completely different.

@atm451

4 жыл бұрын

@@rustyATV thsnks too your videos I now know my frame is sn 89.. I have a 88 trx engine in a box, it's been welded here an there and leaks a bit. I have an all black atc engine seems identical In the quad, got it off eBay 10 years ago and it seemed to be in New condition..? I need to refresh one but wondered what one would be best to do . Thanks for your time , would the trx engine be stronger?

I could, but I'll need to ask DeoVindice for permission first, since it's his porting specs. Actually, have you tried to message him on here? He's a 250R guy and would likely be more than happy to talk shop.

You have any knowledge of the Duncan racing power valved cylinder ? I hear they are rotax I’m not sure how true it is.

@rustyATV

4 жыл бұрын

I have a Duncan cylinder. Only a 265. Yes, it has a RAVE powervalve unit, though I think the guillotine is proprietary to Duncan. I've not used another powervalve cylinder, so I can't compare. Early on I had a stripped cylinder head stud due, I think, to the quality of the metal. Sent it back to Duncan and they repaired it, though not through any warranty as I got it second hand. It's a very fun cylinder; could roll on the throttle into wheelies where my OEM ported cylinders couldn't, though I think that's in part because my OEM cylinders were tuned for a little lower end power.I never raced the Duncan, but I felt like it needed a little more work to make it a good woods cylinder for me.

Will a cr250 cylinder fit a trx250r motor? If so what year?

@rustyATV

9 жыл бұрын

jonh cox Short answer: No. Long answer: It's been done in the past and used to be a kit, but it's totally not worth it since they started making aftermarket cylinders about 20 years ago, even more so now that there are powervalved cylinders..

@RBSTI3 Whoops! Missed this comment. Sorry! I've read it's around 9000RPM.

When Honda said they Detuned the 86 TRX from the ATC 86 engine what does that mean? What did they do?

@rustyATV

Жыл бұрын

It's been a while since I looked into this, but what I recall is they dropped the compression for the TRX with the thicker head gasket. I think Honda was concerned that the heavier weight of the Quad might cause reliability issues (detonation) with the engine. I'm pretty sure before I went to an after-market cylinder that I swapped in ATC head gaskets to bump the compression up for racing, though I might have also used an aftermarket cylinder head with a little more dome volume.

@erichott4671

Жыл бұрын

@@rustyATV TY

Very informative man! Tell me something,,I have the cr 500 motor that came off the gocart on my channel and want to sell it . It"s still only got like 10 hours on it and it"s puched out 80 over. What is it worth? Complete with everything. Send me a message if you know.

89Trx 250r 415cc

That's the nice thing about a Blaster; they're cheap and plentiful. Why don't you make a video of what you're doing and post it? I'm sure some people would be interested.

what does it mean when you have a 88 cylinder with a spacer plate?? thats what i got on mine. i thought you just used a plate on a long rod motor with a 86 cylinder!

@brandonphillips4553

5 жыл бұрын

It means you have a 87-89 long rod with a 85-86 piston.

Do people prefer 86 early or 89 late? Power for power stock?

@rustyATV

8 жыл бұрын

+mike golden Theoretically, all other things being equal, the early cylinders are supposed to make more power because of the open intake and slightly more aggressive exhaust timing. Really, though, I don't think its significant enough on the 250R to worry about hunting one down. I used the 86 and 88 in the video, both, for woods racing and really didn't think the '86 was much better. After it cracked, I ran the 88 in the A class and was able to hold my own. They were both ported and bored at that point, though.

@sharplespaul

8 жыл бұрын

I see thanks for the reply.im picking up a 86 ,however most rave for 88 89? Must be frame.again thanks!!!

@rustyATV

8 жыл бұрын

+mike golden Well, I believe they upped the compression in 88 and, yeah, the quad was something, like, 20 lbs lighter due to numerous changes. That said, you have a few options for raising the compression on the 86, as the 88 TRX and CR250 head gaskets are interchangeable. You'll need to be careful which head you use with the CR head gasket because its really thin, but i used the CR gasket at one point. You also have options for base gasket thicknesses from cometic, that will let you lower the ports. The chassis is a different deal. There are geometry differences, but there are things you can do to shed a little weight. Personally, though, I believe that after 30 years, it's better to have the '86, because they're the toughest frame of all the years.

@sharplespaul

8 жыл бұрын

I'm only 150 lbs I'm not worried about the lbs..and I'm only going to do scrambles if anything..but also ..did you post you were using ya Pistons as well? ..its bored 40 over on fresh rebuild so I beleive I'll get good use out of the cylinder I'd I stay on top of piston and rings..

@rustyATV

8 жыл бұрын

+mike golden "ya" pistons?

Nvm I never said that | | \/