Knocking........not a bottom end problem.

[Nightbiker07]

ok, i bought the bike. when it was running, it sounded like there were migets in there with s trying to get out.
Solution: buy main bearings, rod kit, crank.
so, the main bearings, seals, rod and bearings, and crankshaft are new (crank newly used, all in tolerances)

so upon re-assembly (using old top-end, no fresh bore piston, rings, etc) the knock is still present, although not quite as loud as before. the knock did not go away and comeback, it was present upon the FIRST firing.
the piston wrist-pin was not loose on the wrist pin bearing,, whole assemble is nice and tight, Eliminating (i think) bottom end bearing trouble.

could it have been the piston in the top end making all that noise?

possible reasons include:
1. Timing off
2. Piston loose and rattling inside cylinder
3. well, its your jobs to give me this possibility.

so, how do you set the timing on this thing? the only way to adjust it from what i can tell is to remove the flywheel, but then you cant adjust while its running to get it right.

[SYKO]

have you ever had an air cooled 2 stroke? they make ALOT of noise, alot more than say a liquid, you say every thing is withen specs? it sounds like your experencing alittle piston slap

[NINJA]

Could it be your counter balancer bearings?

[Nightbiker07]

nope. counter balancer bearings are out, because it knocked before i put the new crank in it (other crank was a balanced crank, and NO balancer was present in the case. did not vibrate)

never owned a air cooled 2 stroke (or a liquid for that matter). this baby popped my 2 stroke cherry, but it is definitely making noise. we think its piston slap, but i just want to get opinions and other things to look for.

when touching the bottom end, it all feels smooth. when i touch the top end, it seems to be vibrating and shaking.

[NINJA]

Well, then I'd say you got a serious case of piston slap going on. Fix it before you shatter a skirt and wreck that new crank.

[Nightbiker07]

yeah, its all apart.
im putting my fresh 300 kit on it, just trying to figure out what that tarded spacer plate is for. if the bottom end was shaved, ill need it. if the top end was molested, i could care less i got a new one.

[cr480r]

nope. counter balancer bearings are out, because it knocked before i put the new crank in it (other crank was a balanced crank, and NO balancer was present in the case.

so the counter-balancer has been removed? could it be the clutch?

[Nightbiker07]

it knocked before it had a counter balancer. now it has a stock crank with a counterbalancer. the bottom end rebuild helped, but did not solve.

touching the clutch cover, smooth as catshit. if the new topend does not solve, cluch basket will be the next thing. after that, i will be out of options...