1990 CR125 bottem end question

I have a 90 CR125 I just picked up for dirt cheap for a restore. The crank is locked up. I've never done a bottom end on a 2 stroke but have rebuilt some engines in the past and do all my own work and am very mechanical. Wondering if anyone has any tips on this as far as disassebmly and re-assembly. Thanks

Go on YouTube and search for 2 stroke bottom end rebuild. You will find the series made by Rocky Mountain atv to be awesome. Yeah they are working on a Yamaha but it is much the same. That will give you a pretty good idea of what your getting into. You will also need a case splitter and crank installer which run about 120 bucks together. Oh and a flywheel puller which is another 12. Stick with oem preferably or hotrods crankshafts and ideally oem for bearings and gaskets. Ask yourself if it you really want to keep this bike and ride it for awhile because by the time you buy the tools and parts for a full engine rebuild you most likely won't be selling the bike for a profit, but that shouldn't deter you if you plan on riding it. While your in there replace every transmission bearing that is at all suspect since its apart and for sure the crank bearings. That's probably what your problem is anyways. Any buy a Honda factory service manual. Do not attempt a full engine rebuild without one. Do you have the top end off the bike? You may have gotten lucky and the piston is frozen up and no damage occurred to the bottom end. I can't stress enough though how important it is to thoroughly check over everything and replace if it seems suspect. There is NOTHING worse than going through all that effort and money just to rip it back open again and chase gremlins or even worse have the engine lock up again.

Thanks Curt026 great info. I will look  up the vids. The previous owner is pretty sure it's the crank but will be opening it up soon. I've got a shop manual so I'll look up the tools. Def keeping the bike to race it in the VET class here in NJ. The frame just went out for powder coat this week and going to make it into an old Factory Honda 125 race bike

I have rebuilt a few of them engines do as above but before buying new parts look on a good oem parts site that way you will be able to cross ref parts of other years that will fit your bike take your time use Honda oem bearings in the crank cases and if you only buy one oem gasket on your rebuild make it the main crankcase gasket on my own bikes i use Honda oem bearings and seals plus gaskets more money but have had great results just a personal thing 

ok guy's thanks. Do you guy's recommend any OEM sites for Honda parts?

Hondaeasttolode

Partszilla

Or service honda

www.motosport.com.....they have all the OEM parts and aftermarket parts

Be sure to always check shipping prices at each place. Those $3 items can turn into $13 so be smart about ordering from wherever.

Yeah.My shopping list at motosport end at R9000 and with al the taxes it ends to R14000(it is south african rand)

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now