Piston detonation

J

jesseSRX

New member
Joined
Mar 2, 2007
Messages
49
Age
53
Location
Cross Plains
Can piston detonation be caused by an electrical issue? Second motor in a 2001 SRX and the same piston popped on both. (Piston furthest from the clutch) Carbs appear to be clen without any issues.

any suggestions of things to check?
 

Second motor, or did you just fix that cylinder the last time? Try to give us some more details of your setup in order for us to help.

What jetting?
Any mods?
What fuel are you running?
 
totally different motor. Not sure about mods or jetting, I bought the sled used. standard 92 octane fuel. Since the same piston popped on both motors, i was just wondering if it could be an electrical issue.
 
did ya use the same carbs on both engines? i think the only way for the electrical to cause deto would be for the cdi to over advance the timing ,but that would most likely show up on all pistons,and i,ve only seen that once on a t-cat not on a yammi.
 
I have seen a doo blow many times due to a bad cdi, not retarding the timing at WOT.
I don't know if yamaha pulls timing on top or not.
 
IMO:
You have to look at what was in common between the two engines and systematically elliminate a possible problem:
ie:
-carbs? ensure they are thoroughly cleaned[check posts here] + properly jetted
-fuel pump? ensure working properly and not parially plugged ect
-fuel line + filter? not plugged or cracked ect
-carb boots, spacers, gaskets? not cracked or somehow sucking air
-air box? if its gutted put the shelf back in
-heads ? have they been modified
-fuel supply? may not be the octane you think it is
-has someone installed a race CDI?
I'm sure you get the idea...you have to check everything that could cause a problem. Just because one cylinder is going down doesn't mean the other two aren't close as well...a melt down has to start somewere!

JM.02c
 
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