1980 XR250 smoking


I have a 1979/80 honda XR250 - initially I had problems with it not being able to rev. this was tracked down to a blocked exhaust. seemingly it had a bent exhaust valve and a burnt out valve (these have been repaired). the bore apparently "looked good" so no ring job was done. now it starts and runs fine, but puts out a bit of smoke (blue)- not excessive but enough to erk me. it reads 175 on a compression test (190 new?) and if I add a bit of oil prior another comp test - it stays at 175.

anyone have any insightfull messages of help ?



Did you hone the bore , fit new rings and valve stem seals ?

My first guess would be valve stem seals.

I started to disassemble the engine, but couldn't budge the cam bolts - took it to a bike shop and they removed the head, replaced the burnt/damaged valves and reassembled. it was these guys that said the bore look good, but when I got it back the head was back on. now I did assume they would replace valve seals etc. perhaps I was wrong. I guess because it still has pretty reasonable compression the compression rings are good, but maybe that oil control ring has seen better days...and, as I mentioned, if I dribble a bit of oild in the bore the compression stays the same - that would indicate to me the valves (adjustment way out, decompression out, valve burnt or stuck).

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