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Look at my left side piston it's F***ed!


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Hey hows it goin everybody, one day while i was riding my quad after i serviced it, like changing tranny oil ,cleaning air filter, giving it a wash job. I was coming back home from my friends place and just as i reached my road It's like my quad ran out of gas and just died, I did a compression test and my left side was zero and my right hand side was 100 PSI, so i was wondering if any of you guys could help me out with my problem? what could have caused it? ahah If you have any more questions just ask. The left hand piston is the one on the left of the picture of both pistons.

 

Thanks for your help.

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Perfect example of pre-ignition which is untimed auto igntion, caused by hot spots in the cylinder could be carbon buildup-pitted dome-gasket edge-over advanced timing even. Something is getting red hot in the combustion chamber and igniting the intake charge

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These are both the pistons together like i said the left hand piston is on the left hand side ahah.

 

 

Were you, by any chance, WFO in 6th for a distance before this happened?? What generally happens is detonation. Your see thru hole is a tell tale sign of that. Most of the time, a lean banshee will be fine until you run it out for long distances. This will cause a gradual EGT rise until well in the red and since an expansion chamber motor will recirculate exhaust to the top end, this causes rapid heating and uncontrolled flame front propagation thus detonating. may need to jet for long hauls on the open roads.

 

 

Brandon

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Were you, by any chance, WFO in 6th for a distance before this happened?? What generally happens is detonation. Your see thru hole is a tell tale sign of that. Most of the time, a lean banshee will be fine until you run it out for long distances. This will cause a gradual EGT rise until well in the red and since an expansion chamber motor will recirculate exhaust to the top end, this causes rapid heating and uncontrolled flame front propagation thus detonating. may need to jet for long hauls on the open roads.

 

 

Brandon

 

na man, its pre-ignition they are very different, in detonation damage is on the side of the piston usually the exhuast side, u should be able to ride wot for a good period of time.

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na man, its pre-ignition they are very different, in detonation damage is on the side of the piston usually the exhuast side, u should be able to ride wot for a good period of time.

 

 

huh, last time we had a motor that made a holy piston on the dyno, it was lean and "detonating". We decipher the difference with piezoelectric sensor data overlaid on the ignition pulses.

 

Brandon

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detonation is not caused by a lean mixture its caused by unburnt trapped end gases on the piston crown combusting, usually on exhuast side becuase its the hottest side u had to have another problem in ur motor what did u see with the data on the pulses an increase?

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detonation is not caused by a lean mixture its caused by unburnt trapped end gases on the piston crown combusting, usually on exhuast side becuase its the hottest side u had to have another problem in ur motor what did u see with the data on the pulses an increase?

 

 

Increase of what?? you tell me. What is my problem??

 

Brandon

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well before my left piston blew a hole in it, my one right hand side spark plug metal cap was loose for a while and i never thought nothing of it and it was skipping sparks sometimes and then when i tightened my sparkplug cap back up and i went riding and got back it blew up so that might explain something

 

Thanks

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well before my left piston blew a hole in it, my one right hand side spark plug metal cap was loose for a while and i never thought nothing of it and it was skipping sparks sometimes and then when i tightened my sparkplug cap back up and i went riding and got back it blew up so that might explain something

 

Thanks

 

Did the plugs themselves ever back out on ya?

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Blowit u have detonation mixed up with pre-ignition.

 

shee racer u need to get this figured out before u rebuild, does the dome look all pitted up? is there alot of carbon in ur motor? burnt gasket edges? if not u really need to check ur timing

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