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What is detonation


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man, could you take some tinier pics for me? without seeing more detail, i would have to say it most definately looks like a lean burn-down. you can see the typical melt-out through the exhaust. that ring "snag" is it breaking off because the ring land was blown out. a closer pic could show if it was actually melted, or spark related, which can also suck a ring land....

 

 

these fellors are correct!...air leak - lean - fried piston n dome = more $$$$$ sorry bro next time do a leakdown test!..also from talkin to a few guys i know f.a.s.t aint cherry on building bikes and knows what he is doin!..

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Yeah sorry about the pics... I took them with my phone. But yes the domes were new and it looks to me like the ring is broke. There are pieces of it all over the piston. So the general consences is it's a lean condition? How could this happen with those jets?should the builder be responsible for this? AK, what do you mean by the ring land was blown out?

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these fellors are correct!...air leak - lean - fried piston n dome = more $$$$$ sorry bro next time do a leakdown test!..also from talkin to a few guys i know f.a.s.t aint cherry on building bikes and knows what he is doin!..

As far as the leak down test the builder did that along with the squish. I don't know where the air leak would come from sence the intakes are new the leak down was done.....

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As far as the leak down test the builder did that along with the squish. I don't know where the air leak would come from sence the intakes are new the leak down was done.....

 

 

when you tear it down take some more pics for us..here is a link i started on another site and most say from what they see in pics lean cond then another builder said it wasnt a lean condition so who knows until we see more pics...here is the link

 

http://www.planetsand.com/forums/ubbthreads.php/topics/1064279/lean_condition_or_what#Post1064279

Edited by tripledsracing
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when you tear it down take some more pics for us..here is a link i started on another site and most say from what they see in pics lean cond then another builder said it wasnt a lean condition so who knows until we see more pics...here is the link

 

http://www.planetsand.com/forums/ubbthreads.php/topics/1064279/lean_condition_or_what#Post1064279

Yeah I just checked that out... I don't think it was a crank failure cause that's what happened befor he built this motor and it looks a little different. The last time it was the piston actually smacking the dome. This time it blew that chunk of the piston and the bounced around in there tearing everthing up. I think he is actually building the crate for it now and sending it out as soon as he can.

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well, like i mentioned, a "miss-spark" (made up term) can suck a ring land, which is the "land" or piston area that holds the rings in...... the low detail pic didn't leave enough for me to see the difference. they can look similar, and you break a ring half the time you have a melt-down, which is what makes you stop, or it back-fire. i suspect this, because i don't see any sign of detonation, or melting on the un-damaged parts of the piston crown or dome. i have seen both first hand. did it seem to shake a lot, or pop at idle and lower rpm's? the lean condition can come from a glazed carburetor surface, or under-tightened clamp, as well as plugged jets, fuel separation, or other flow issues, even the gas cap. if you can get a more detailed pic, i can probably tell you exactly what happened. (fuel, spark, or snag) this tear-down is very crucial in paying attention to detail and taking pics, due to the nature of the implications. i'd hate to see uninformed actions

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I would say that since it's only one side that had a problem, it was an air leak somewhere on that side. I didn't catch who put the carbs on the motor but it could've been something as simple as that that caused your problem. Always do an air leak test before you go starting a new build. If the builder did this before the carbs were put on and it was fine, then theres your problem. You didn't after installing the carbs, before starting.

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I would say that since it's only one side that had a problem, it was an air leak somewhere on that side. I didn't catch who put the carbs on the motor but it could've been something as simple as that that caused your problem. Always do an air leak test before you go starting a new build. If the builder did this before the carbs were put on and it was fine, then theres your problem. You didn't after installing the carbs, before starting.

how do you do an air=leak test with the carbs on, and it not running?

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We didn't do the leak down test after it blew up because as soon as it happened he call the builder and he said to take the head off and let him know what happened. For those who asked who put the carbs on, my buddy did. But they were all tightened down good with new intake boots. This was no hacked together build. Anything and everything was replaced or fixed. I posted a couple pics of the bike just to show the quality of the work done on this bike. Not a penny was spared.

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