Broken Piston

[hondatv]

OK motor heads can anyone explain why this happend?
I was told this piston was a flat top and machined for valve
relief and less compression. Plug was dark brown: Jetted to engine builders recommendation

http://www.geocities.com/scooter20735/piston1.jpg

[Dunlap]

Your ex valves are white showing it was lean. You piston shows so much heat in the middle that it has detonation the top of the ring groove off. The grey coloring is the sign of death to any motor. Check for air leaks.

[K_Fulk]

How long do you let it warm up? I had a ring come off part way on my 440. It went down twoard the bottom of the piston. I figured i caused it by not warming it up enough.

There are a lot of diffrent things that could cause it. Just be glad it didnt look like this.

[DragVette78]

if u need another piston i got one to mske it a 426 ill sell ya for a hundred bucks with gaskets

[hondatv]

DragVette78, Thanks but No Thanks. It is to small, I need a 91mm piston.:(

[hondatv]

Mickey, I just sent you an Email.
And thanks, I am having the head pressure tested tomorrow.

[trikemoto85]

one of the main causes of detination is too low of octane...when u get the new piston try puttin higher octane in it eh?....octane rating I.E. the resistance to detinate

[hondatv]

trikemoto85, I plan on running VP Blue next go round. I found a big part of the problem, The piston is coming out the cyl. .007th.
:confused:

[trikemoto85]

what do u mean the piston is comming out of the cylinder .007"?
are u talkin about clearance between the cylinder wall and piston

[Knips178]

Be carefull with that vp blue gas, i've heard it gums up your carb.

[hondatv]

The piston is .007 into the head gasket. (above the cyl)