Noisy Top End

[ILLKILLUTHRICE]

I Have A 83 250r And Any Time The Bike Comes Under Any Kind Of Stress Or Load The Top End Makes A Weird Rattling Clanking Noise. I Have Taken The Top End Off Myself And Looked At The Piston And Found Out It Was Bored Out 60 Over. Theres Not To Much Slack On The Connecting Rod And The Piston Looks Pretty Good. So If Anyone Knows What This Could Be Please Let Me Know Thanks

[ridetrikes250R]

piston slap, a quick way to check, take the head off, bring the piston to TDC, and then try to "wiggle" the piston, if you can get the piston to "wiggle" alot back and forth, thats your noise... its time for mayb a new piston and a good bore and hone

[ILLKILLUTHRICE]

Would There Be Any Wear On The Side Of The Piston From This

[bones200x]

Yes,there should be wear on piston. Possibly wear on cylinder. You need to mic(measure) cylinder and piston. That will tell if it worn out. The most you want is .004-.0045".. Make sure bearing and pin is good also. I have seen just the pin wear out. And cause the piston to wear.

[NightBiker07]

i have the same problem. did a complete bottom-end rebuild, even went as far as to get a new crank. but it still makes the same noise...........leaving the only other possible option that the piston is loose in the cylinder. it sounds like a knock, correct? but kinda high pitched?

ive got a new 300 bigbore kit for my R, so im just switching it over! woot!

[dovesprings250R]

sounds like detonation to me. High pitched, knock........under stress. What octane gas do you run? Try higher octane. Maybe mix race gas 50/50 with 91 pump gas. That worked for mine............