Knocking noise

Azz

Member
Mar 8, 2003
21
0
When the bikes running, i can hear a slight knocking noise...Is it the pison or something?? The bike appears to be running fine, is it something serious though?
It wouldn't have anything to do with the fuel would it??
Thanks!!
 

RM_guy

Moderator
Damn Yankees
LIFETIME SPONSOR
Nov 21, 2000
7,045
208
North East USA
It could be several things.

A low octane gas could be causing detonation that can sound like knocking. Min. octane for a stock bike is usually 92. Modified, high compression bikes need higher octane.

Is the piston new? A worn piston can slap against the cylinder and make a racket.

I'm sure others will add some more.
 

Joepro9

Member
Feb 17, 2001
503
0
does the noise change when you pull in the clutch? It could be clutch rattle. Depending on how old the top end is it could be that, or the gas.
 

Azz

Member
Mar 8, 2003
21
0
Thnaks guys....First of all, i'll get some decent petrol for it....I was just using stuff that was lying around for a while, and i mixed the oil up pretty roughly aswell, so i'll do that and see if it changes anything..
Thanx!
 

JTurn36178

~SPONSOR~
May 17, 2002
131
0
Does your noise only happen on deceleration? Or is it a constant thing?

I have three Yamahas and all three have that ailment on deceleration. I talked to Eric about it, he suggested that I work on my jetting. I have thouroghly ((*?&%) how do you spell that word??) checked the play on the rod on one of the engines, and can find no fault there. It's an ongoing learning expierence.

Hope this helps, good luck.
Jim
 
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