how difficult to rebuild a 250R motor?

[Jim mac]

I got my 250r motor in a box all disassembled. The guy that took it apart owns a bike shop in town, plan was to freshen it up with a new piston, crank bearings, and install a new stator. But funds ran low and now I have the trike. I called the shop owner today and he told me if the crank needs rebuilt, the price would be 500 bucks for him to put it back together. 430 bucks if the crank didnt need a rebuild. 80 bucks to have it bored if needed. I furnish the bearing/seal kit, piston kit, gasket kit.
Im going to mike the bore, but it looks clean inside no ridge etc. and there is no play in the connecting rod. So the question is, just how hard is it to put it back together? Ive got 200 bucks into the whole trike now. figure another 325 for parts. And id be okay with that, but add in another 430 for labor and im into the thing for more than I could buy a running water cooled 250r. jim

[TheRealFatShady]

Even if you aren't able to do it yourself, try finding a reputable home-based mechanic. I found one one craigslist, he does full engine rebuilds for $100-$150. $430 or $500 is way to much, like beyond reason.

[Dirtcrasher]

Jim, the 250R is one of the simplest motors to rebuild. But, little tips and things you pick up from others can help it go even easier.

Your problem is "it's in a box" and it's allot harder to put things back together that someone else took apart. Even when you take stuff apart yourself, the longer it takes to get it back together, the harder it is.

I always zip tie my tranny gears in place and bag them. I'll put a note on the bag "missing thrust washer" or something so no matter when I get to it, hopefully I'll get it running again.....

The R motor is fairly simple but you still need a few special tools (or the ability to make them) to get it back together. Some things, like main bearings, just can't be pounded on like an axle bearing. And pulling the crank in is essential to keep it "true" or it won't last 25yrs like it did originally.........

[jeffs250Russell]

cool thread

[Jim mac]

crank is already pulled, cases are apart, tranny clusters are wrapped seperately. I think I read were its a matter of freezing the bearings and warming the case to drop in the bearings. I do have access to a press at my work. Jim

[harryredtrike]

do you have a manual?have you rebuilt a motor before?are all the parts in the box?can be a good experience for you or could be a nightmare.its not hard but it is technical

[Dirtcrasher]

They can all be done by allot of people.....

It's whether it will last another 20 years that will be affected by the install procedures.

The bearings do drop in fairly easy, but then you have to get the crank INTO the bearings, I freeze the crank..... Then pull it into place with real tools, or homemade tools like I do.

People have to understand that in some cases you have to contact the bearing OD, in other cases you have to support the bearing when "pulling" the crank in (unless it pulls right in....

Bear in mind that the left crank seal is suppose to sit either 5 or 6MM deeper than flush or it doesn't seal. Any further and the little oil hole on the cases can't get oil to the main bearings.

Thats why I say it's tips and tricks and a service manual that get it done well and your confident you did it right.

I'd stone those cases flat, get everything else ready to roll and then apply a thin coat of 3 bond (I use an acid brush) and get them together within 5 minutes or so.

G-luck, keep posting. No harm in asking questions as long as people are willing to learn :beer