cracked piston

[hauser2169]

hey guys. remeber when i wrote a thread about a my quad feeling like no compression. well i took off my topend and looked at the valve from a diff angle and its bent badd. then at the piston and on one part of it i can see the compression ring. thats how much chipped off of the piston. what u think caused it. bent valve???

 

[ratchracing]

sounds like your timing must have been way out, causing your valves to contact the piston, which would definetly bend a valve and could cause damage to the piston like you describe. Time to replaced the valves and piston, make sure that the cylinder is still in good shape (no gouges) give it a hone, grind the valve seats, reassemble and make sure that the timing is correct.

Were you able to find the chipped off peice of the piston? if not you'll have to tear down the engine and get it out..... it could cause huge problems if its floating around in there somwhere.

 

[hauser2169]

it looks like everything is melted on to the dome. im going to try to get some pics tonight ughh so much for riden this weeknd

 

[ratchracing]

you must have overheated it big time if its melted, were you running it too lean or what?

 

[troys3175]

What compression and what fuel are you running also?

 

[hauser2169]

the timing jumped. thats the only possable explanation.

 

[ratchracing]

if everything is melted there is no way it was just the timing. post some pics, a picture is worth a thousand words

 

[hauser2169]

thats the best pic i could get

 

[dswwarrior350]

The piston may have seized and cracked

 

[troys3175]

That is a really shitty pic. If it was in focus I think we could help you more.

 

[wie1086]

What went wrong really doesn't matter now. Tear it down and figure out what it is going to take to make it right again.

When you pulled the head, was the sprocket still tight on the cam? Make sure there is no damage to the keyway. Its obvious you will need a valve job, piston, rings. Throw in a Timing chain and inspect the head of the chain tensioner. It appears you have only pulled the head, so get the jug off -its only one more bolt. Then you can inspect the lower rod bearing and get a good look at that piston.

 

[hauser2169]

i got the jug off that day. just dint take apic. i will get one and post it thanks

 

[87warrior]

it looks to me that it was running to dam lean and sonething was in the cyclinder that was not supost to be in there caus if it had a bent valve it would of taken out right below the valve notch in the piston and it was not at first something was in the cyclinder and it hit the valve and then it took out the piston well sorry to see it like that but it looks like time to bore or for a new sleve