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View Full Version : rebuilt the top end on my R last night



danimal95
03-01-2008, 06:40 PM
so i decided to put a new top end on my 85 R after i bought a mildly ported jug and cool head off craigslist for $140.well i tore it down and to my suprise it was still on the original bore:beer now ive been in the 2stroke world for a long time and never have i come across a machine that was even close to the same age as this one that was on the original bore,so im guessing that for most its life this was a pampared machine which the rest of it reflects:p btw i measured the piston to wall clearance this morning and it was at .010 possible a tight .011 which is way past spec.........also it freggin screams now:w00t:

Liquid-Darkness
03-01-2008, 09:02 PM
So with the build did you: replace the rings, pin, c-clips, wrist pin bearing, and break the glaze on the jug? Some times people re-sleeve their cylinders. That would put it back to a stock bore. .003 clearence with a forged piston, .002 & 1/2 with cast pistons is what most people run for clearence. Remember your 3 heat cycles before you run it hard, or the head will come loose and leak.

danimal95
03-01-2008, 10:04 PM
So with the build did you: replace the rings, pin, c-clips, wrist pin bearing, and break the glaze on the jug? Some times people re-sleeve their cylinders. That would put it back to a stock bore. .003 clearence with a forged piston, .002 & 1/2 with cast pistons is what most people run for clearence. Remember your 3 heat cycles before you run it hard, or the head will come loose and leak.

all of the above was done except the 3 heat cycles,ive done 2 so far and the ehad was still torqued correctly,there is 3 thou clearance on this jug....also it appeared to have the original head gaskets and base gaskets on the oe jug,doesnt really matter though i just found it interesting:)

Somekindofjerk
03-01-2008, 10:07 PM
Danimal you should make a thread about your car in the forums! Thing from reading seems sick!

Dirtcrasher
03-01-2008, 10:14 PM
Allot of privately owned 250R's are still on the original bore. I had one about 2 years ago myself, of course it was long overdue but they just keep going and going and going and.

Most of them have well worn main bearings too.

danimal95
03-01-2008, 11:58 PM
Danimal you should make a thread about your car in the forums! Thing from reading seems sick!

thanks i may just do that:naughty: