gen 4 with 87 engine

[rancid1]

well i got me a complete 05 crf250 bike for 400 dollars, with jacked motor. so i pulled the motor and sold it for parts ebay. just picked up a complete 87 cr500 that needs a piston for 200 dollars. so im on my way to start my conversion. is everbody making all there own swap parts or does somebody offer any of the parts for the frame and swingarm to help with the swap. are you running the crf swingarm bolt. any advise i could use it, thanks.

[Kuma]

there are a few on the site that can set you up, pstoffers comes to mind, he can do th emods or offer a DYS kit with all the peices.

You probably want to pull your waterpump cover off to see how bad it is, pre '89 are mag and the waterpump housing gets eaten up.

[rancid1]

what needs to happen on my swingarm bolt through the 87 case, just drill the hole larger through the 87 case bushing. would that work ok.

[cryzsurfer]

I tried drilling mine out to no avail. When I split the cases I took the bushings to work and had a machinist put them on a lathe. He said "they're harder than a preacher's dick at a double wedding". Better use a lot of coolant on a Bridgeport if you go the drill route.
craigus

[black]

I am not saying this is the best way, but it is a way if you don’t want to split the cases. I drilled mine out with a masonry drill bit, using two sizes bits and not jumping straight to the final size. Use a lot of coolant and drill one side and then drill from the other side(not from one side right through). There wasn’t the right size bit available on my last bit so I grinded the head smaller. The masonry bit will walk through it.

[plynn41]

You're going to run into the same problem I had trying to fit my '88 engine into an '05CRF250R frame--the carburetor won't clear the shock spring due to the reed cage casting on the cylinder being 7mm longer on the pre '89 cylinders. You may want to consider selling/swapping your '87 engine for an '89+ model.

[rancid1]

You're going to run into the same problem I had trying to fit my '88 engine into an '05CRF250R frame--the carburetor won't clear the shock spring due to the reed cage casting on the cylinder being 7mm longer on the pre '89 cylinders. You may want to consider selling/swapping your '87 engine for an '89+ model.

cant i just do a reed spacer cut on a angle.

[rider624]

Yes, you can, but it still just barely touches at the very top of the stroke when the shock compresses all the way. I've got an 06 250f chassis with an 86 500 stuffed into it, and I put the reed block spacer in it, but like I said, it just touches at the top. I actually had to keep an eye on it, cause over time (6 months of every weekend riding), it would actually rub through the clamp holding the airboot to the carb. If you put a much thicker airbox spacer in, (3/4ish) I believe you will eliminate this problem. My recommendation would be stay away from the reed block spacer, and go with the bigger airbox spacer.