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61 mm cylinder block

sniping_area

Super Veteran

it seems the noise is coming from the cylinder head. did you removed the lever (see picture) inside the camshaft sprocket which activates the decompression pin through centrifugal action? without the decompression pin it would be free to bounce and create noise. this would not affect the engine performance but would create knocking noise.
i didn't remove my lever... :D i don't think its coming from that part...
 

wvlfonlus

New Member

it seems the noise is coming from the cylinder head. did you removed the lever (see picture) inside the camshaft sprocket which activates the decompression pin through centrifugal action? without the decompression pin it would be free to bounce and create noise. this would not affect the engine performance but would create knocking noise.
i don't recall removing the decomp pin...funny thing is, it only makes that "tukotok" sound when it is idle..once you rev the engine it becomes smooth...i haven't open the engine yet, it might be a loose bore..snipping area might be correct...i'll have it check with a compression tester at yamaha 3s probably tom.

i'll be taking note of all your input...so far decomp pin and loose bore might be the cause... i don't believe its the conrod since yamaha conrods are the best...
 

aizarn20

Super Veteran
sir do we need to change into big head when changing to big block?is this proper combination sir?camshaft turbo+r v spring+r ignition coil+r clutch spring+r clutch plate+60 mm block+r crankshaft....what is lacking sir?i have a rextor cdi now...this mods havent install yet....im finding a good mechanic...they suggest me in egv aka bong in tarlac...
 

saDam

New Member
have the same probs with tiny snipeee..but we have figure out that noise and that is the timing chain tosser.. we replaced the timing chain and chain tosser with new one and the noise is gone..
 

Rolly

Super Veteran
have the same probs with tiny snipeee..but we have figure out that noise and that is the timing chain tosser.. we replaced the timing chain and chain tosser with new one and the noise is gone..
you might be referring to the chain tensioner bro..
 

Rolly

Super Veteran
i don't recall removing the decomp pin...funny thing is, it only makes that "tukotok" sound when it is idle..once you rev the engine it becomes smooth...i haven't open the engine yet, it might be a loose bore..snipping area might be correct...i'll have it check with a compression tester at yamaha 3s probably tom.

i'll be taking note of all your input...so far decomp pin and loose bore might be the cause... i don't believe its the conrod since yamaha conrods are the best...
"it only makes that "tukotok" sound when it is idle"... the more I suspect the lever is causing the noise because during idle, the revolution of the engine is not that smooth and causes the lever to bounce back and forth. at high revolution, centrifugal force makes the lever to just stay outward and not bounce back and forth.

"i don't recall removing the decomp pin".. if you changed your stock camshaft with a racing camshaft, there is a great possibility that the installed racing camshaft has no decompression pin.
 

Rolly

Super Veteran
original

this is what i am talking about... this is a much better illustration than the drawing from the manual.:D
 

Rolly

Super Veteran
the only disadvantage of removing the decompression pin assembly is that you have to rivet it again in place if you put back your original camshaft and you wish to have a decompression pin installed.
 

wvlfonlus

New Member
got the chance to crack open my engine yesterday...and just as i suspected loose bore..... next step CMR 62mm....I'll post pix and videopf the assembly tomorrow....my wallet feels 1000 p lighter...:(
 
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