Full Version: Top End Rebuild On 86 250r
Doing a top end on my two fitty and I've never done this before, any helpful suggestions or tips would be cool. It's currently stock except for pipe and jetting.
easy, drop the jug off at a shop, have it bored, buy the piston for that size bore, and then put it all together
What KTM said and go buy a manual, it will tell you what to do. It is pretty simple once you get a few under your belt. I have the clymer manual for mine.
time for big bore. 
I just rebuilt my 250r (85 atc)was the first time it was apart and it looked very good i took it apart to replace the head gasket with the cr250 head gasket and base gasket so i just did a piston and ring while it was apart and added a fmf pipe.Was pretty easy IMO and the improvement from the increased compression was noticable.Was able to pull aaway from my uncles yzf450 slightly on the same hill he pulled slightly away from me wwhen i was stock.hes done the cam mod,jet,filter and pipe but still really comes down to who gets the better start id i do it is histoery if he does i might not catch him(it takes the whole hill to make up the difference)
| QUOTE (bigbadKTM @ Dec 8 2004, 11:46 AM) |
| easy, drop the jug off at a shop, have it bored, buy the piston for that size bore, and then put it all together |
I was tought to buy the piston then bore to match . The guy who I take my jugs to will only do it this way .
You're gonna need a small piston ring compressor. Study up on break-in procedures too.
Good luck!
Good luck!
| QUOTE (MWBbanshee @ Dec 8 2004, 04:45 PM) | ||
I was tought to buy the piston then bore to match . The guy who I take my jugs to will only do it this way . |
yes, you buy the piston first then have the cyl bored. even though new pistons are supposed to be the same sizes (compared to each other for the same size bore) they can be off by a few thousandths of each other, so if you bore the cyl to the next oversize and the new piston is actually slightly smaller than its supposed to be your gonna have to much wall clearance.
| QUOTE (az350x @ Dec 8 2004, 07:42 PM) |
| You're gonna need a small piston ring compressor. Study up on break-in procedures too. Good luck! |
No need for a piston ring compressor. Just get some help putting the cylinder on the piston and use your hands.
always did the rings by hand, by myself...or use a hose clamp that will fit over the piston and rings. about a buck for a hose clamp.
and forgive me for the mix up on the jug and piston . whoops!
and forgive me for the mix up on the jug and piston . whoops!
Line up the rings in the slot...I forgot once when I was tired and I thought I was gonna gpress the whole damn piston
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