i had the same thing happen. it ended up being the rod bearing.
--> Knocking But Running Fine? <--
Motor is the following:
FRESHLY BUILT:
-06 motor
-yx 150 cylinder (143cc for 110)
-Kitaco 143SE piston, rings, wrist pin, circlips
-Mikuni vm26 carb with TBv2 intake.
-PORTED (Mike Castro aka Fuzzimoto) YX head with YX Cam
-chp full-manual cable-cluth with CF primary drive
Valves are set between .002 and .003, when I fired the engine it was knocking,
NOT COMING FROM HEAD. NO VALVE TICK. Head is quiet. No leaks either.
Knocking increases with increase in RPMS. Sounds like the piston is slapping the cylinder.
--Bike runs fine, I was able to cruise it up and down street and DAMN it has POWER. Great compression too.
I thought it might just need to heat up (it was like 40 degrees and I had just put fresh oil in it) and get oil running through it.
However, upon firing it later it still has the same knocking sound and it isn't going away OR getting quieter.
What can it be?
I've done 5+ top-ends including one I just did on my spare 110, with no problems.
Is it this JANKY mis-match of parts I have going on?
FRESHLY BUILT:
-06 motor
-yx 150 cylinder (143cc for 110)
-Kitaco 143SE piston, rings, wrist pin, circlips
-Mikuni vm26 carb with TBv2 intake.
-PORTED (Mike Castro aka Fuzzimoto) YX head with YX Cam
-chp full-manual cable-cluth with CF primary drive
Valves are set between .002 and .003, when I fired the engine it was knocking,
NOT COMING FROM HEAD. NO VALVE TICK. Head is quiet. No leaks either.
Knocking increases with increase in RPMS. Sounds like the piston is slapping the cylinder.
--Bike runs fine, I was able to cruise it up and down street and DAMN it has POWER. Great compression too.
I thought it might just need to heat up (it was like 40 degrees and I had just put fresh oil in it) and get oil running through it.
However, upon firing it later it still has the same knocking sound and it isn't going away OR getting quieter.
What can it be?
I've done 5+ top-ends including one I just did on my spare 110, with no problems.
Is it this JANKY mis-match of parts I have going on?
1 - 5 of 5 Posts
Yea sounds like something crank related 
sounds very con-rod ish. i would pull it apart and check the con rod. don't want to fill that new top end with any more filings...
Yea i'd pull the cylinder and check the rod for play.
1 - 5 of 5 Posts
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