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Showing results for tags 'scratchedcylinder'.
Hi, im new to this forum. I recently got me an NX650(euro), but i didnt check the bike properly before buying it. Found some faults driving it home. Welded sprocket and noisy 4th gear. 23K miles stock. Might be wrong forum, but its the same engine as xr650r if im not mistaken? This is my first rebuild, and it went somewhat bad. A couple of rounded allen bolts(rubber intake carb), bolt to head broke and rounded a allen when splitting the cases. Damages found so far - timing chain stretched, 4th gear broke, some scratches in cylinder, some scratches in oil pump, 4th gear broke. A lot of carbon build up in combustion chamber, guess oil have been burning. Cam and journal seems good. Rockers also seem good, hard to tell. Many pics, more upon request. Now that its teared down, i need some help with purchase list. I dont know what is smart to change while im rebuilding it. Im building bike for reliability - mainly commuting. Power is always welcome, but rather reliability. List; Poured some engine cleaner in combustion chamber and had it upside down over night. Valves didnt leak - guess they are OK? No need for re-seat? Is it necessary to change timing tensioner? Anymore seals or bearings i should change while im at it? Im guessing 4th gear breakdown is the reason for scratches in cylinder and oil pump. Found some metal parts. Why the exhaust valves have been running hot(white) is oil consumption due to scratches in cylinder? Teardown was "fun", looking forward to rebuild it and paint it. Ive done alot of research online, but feedback before rebuild is MUCH APPRECIATED.
Bike is up-jetted to correct jetting, air filter is fairly clean, bike has only got 1200 miles since its most recent top end rebuild recommended is every 6000 miles on this 125 2 stroke road bike, top end was done at garage, always warmed up and ridden nicely. seems to have deep to severe scratches on the piston and cylinder bit, seems to be where the exhaust port is and on that general side. could do with some help on understanding the possible issue so i can stop it from happening again.