sandman3577
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what pistons besides wiseco? at 8200 miles dropped valves in both cylinders at 6000 rpm/anybody use andrews cams?
pistons and rings 08 firebolt xb12r
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mike lowary
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I use CP pistons and Cat 3 cams from NRHS
An extremely rare catastrophic failure... and simultaneously in 2 pistons?
Whats the whole story sandman? Your use/abuse would dictate what new engine to build that will last, because stock obviously ain't enough for you
Whats the whole story sandman? Your use/abuse would dictate what new engine to build that will last, because stock obviously ain't enough for you
mike lowary
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I agree scorpion king. Seems like a bit of info is missing...
I use pistons/cylinders and Cat 3 cams from NRHS as well. Dan at NRHS is pretty awesome.
young scooter
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How do valves just "fall" into the cylinder? Ive never heard of this on any bike or car/truck.
I agree. Its either a one in a million shot of bad luck... or someone not being accurate of what happened. Maybe he meant both valves in one cylinder... or he meant 8000rpm instead of 6000.
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A valve spring or retainer would have to break, and the result would be catastrophic to the head, the piston, and probably the cylinder too. Ultra rare to happen in even one cylinder, much less twice at the same time. I'm sure the OP is just guessing for now, I'm real curious what he finds. Crank pin?
Are Buell engines interference engines? Not that the gear driven cam would ever skip, I'm wondering if valve float at NASCAR rpms could even touch the piston?
Are Buell engines interference engines? Not that the gear driven cam would ever skip, I'm wondering if valve float at NASCAR rpms could even touch the piston?
In this case it would be all 4 breaking... and at the same time.
His fuel pump probably went out.
His fuel pump probably went out.
Thats how this board goes.
Replace... and when that doesn't fix it... then start diagnosis:eagerness:
Replace... and when that doesn't fix it... then start diagnosis:eagerness:
young scooter
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Lol
Barrett
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i don't know, bro. i mean i know he's got a buell and it's kinda like a sportster and a sportster is kinda like my superglide and they're all kinda alike and all, but i rev mine pretty hard and even jump it and never busted any valves. i mean don't get me wrong bro, i bust **** and all, but never any valves.
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"Hey Bubbles, hold my Bud Ice and watch this... uh huh huh huh"
kdawg302000
Well-known member
Im no expert at jumping sportsters, but im pretty sure, he over shot his landing ramp a smidge.
*
Me and my 5y/o watched that about 10 times. After the first one he said..."you can jump those?" Love this little guy.
sandman3577
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no abuse
on a nice road nice day engine at 6000 rpm the engine just made a loud pop sound not a bang like a car engine when a timing belt breaks and a valve slams into a piston. pulled in the clutch and coasted to a stop. when i tried to start it it spun with no compression /no rods out of the cases if a valve spring breaks the keeper comes out the valve drops and hits the piston .the engine is out so monday the top end comes off and i will let you know /but when i did a compression check both cylinders were dead how or why? not a clue.
An extremely rare catastrophic failure... and simultaneously in 2 pistons?
Whats the whole story sandman? Your use/abuse would dictate what new engine to build that will last, because stock obviously ain't enough for you
on a nice road nice day engine at 6000 rpm the engine just made a loud pop sound not a bang like a car engine when a timing belt breaks and a valve slams into a piston. pulled in the clutch and coasted to a stop. when i tried to start it it spun with no compression /no rods out of the cases if a valve spring breaks the keeper comes out the valve drops and hits the piston .the engine is out so monday the top end comes off and i will let you know /but when i did a compression check both cylinders were dead how or why? not a clue.
mike lowary
Well-known member
You mite have dropped a valve in one cylinder and the debris from that got sucked into the other cylinder causing damage. That exact thing happened to me.
mike lowary
Well-known member
Post up some pics of the carnage
Yup.
Please post pics!
Since a V-twin engine is basically two engines that share a crankshaft and you didn't mention it making crunchy and expensive noises while cranking... I'm guessing whatever happened to lose compression in both cylinders, happened to the parts they share. Even popping out a plug would only affect one cylinder and you did a compression check so you would have notice a spark plug missing I hope, haha.
Thats why I'm guessing
Please post pics!
Since a V-twin engine is basically two engines that share a crankshaft and you didn't mention it making crunchy and expensive noises while cranking... I'm guessing whatever happened to lose compression in both cylinders, happened to the parts they share. Even popping out a plug would only affect one cylinder and you did a compression check so you would have notice a spark plug missing I hope, haha.
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