I just got an '86 Honda 250R three wheeler. And I've always wanted to drop a CR500 motor in one. How hard would this conversion be. I know they vibrate bad but I can handle it. Would I need any frame mods? If so what needs to be done? what year motor should I put in it? What are any other mods that I would have to perform for this mod? Where can I get a pipe for this conversion?

 

I did one a few years back, the biggest troubles are the pipe and the kickstarter. The pipe from a CR500 could maybe be made to work but I didn't try it, I had it mad at DynoPort in Syracuse, NY. You'll have to bring the entire bike with the engine in its final position to a two stroke pipe fabricator near you (good luck, there aren't many around) and they will make the pipe and silencer right on the bike. The alternative is to put a whale pipe on if you don't plan on riding the woods or entering any sort of motocross with it. DO NOT use a 250 pipe with a 500 flange welded on, it WILL run like crap and youl'll be very disappointed. I cut and welded the frame for my kicker to clear, don't do that, it was difficult and stupid. Instead I'd space the splined part of the kicker out as needed to clear the frame rail. You'll have to either pull the fenders off to start it which is a hassle or cut a part out of them so your foot and the kicker can pass through. A few more things, cut off and forget about the bottom engine mount, the rear swingarm mount works if you remove the stock "cradle" and put the bolt right through the rear of the 500 case. The front mounts you'll have to make and the top mount on mine was only on one side of the head stay and was welded to the frame permanently after I cut off the little piece the stock two piece mount bolts to because it was in the way. Don't plan on using this bike all the time, especially at high rpm, the motor will stress crack the frame and mounts. Any more questions just e-mail me and I'll do my best to help you. Oh yeak, the motor has to be all the way towards the side that the stock countershaft sprocket was and then space the other side, the chain should line right up and I did an '86 ATC250r so these tips should hold for a 85 too.

 

People have put Pilot cylinders on a 250R and CR500 cylinders on a Pilot. A Pilot and a CR500 have a 79mm stroke. I was told by Crankworks that they have stroked a 250R to 80mm. What I wonder is why not stroke it to 79 and use a CR500 cylinder. Then you would not have the kickstarter problem and you would have a counter balancer. Maybe the trans could not handle the power though.

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Steve Bishop
Banshee
FL350R
FL350R (soon to be FL500R)
YZ490

[This message has been edited by LiveWire (edited 01-08-2000).]

[This message has been edited by LiveWire (edited 01-08-2000).]

 

I think the 500 cylinder is just too big to put on the 250 bottom end, the Pilot cylinder is a lot closer to the 250r's. FTZ racing does a kit for this. Their web site is FTZracing.com they also do great port work (my atc250r hauls now) and they to alot of alcohol conversions.

 

Can you bolt a Pilot cylinder on a 1985 ATC 250R motor??