WTF Caused This?

[Driggs]

Guys....help!!! Fresh top end, just cleaned carbs, 280 jets, Toomey T5's, billet impeller, Fluidyne radiator, everything else is stock. I'm sure it got hot but why? Going to rebuild but don't want it to happen again.

[Driggs]

Can't get the pic to show so here's the link.

 

http://img8.imageshack.us/i/img00006200909261822.jpg/

[Driggs]

Oh, one more thing, I have a Cool Head with 21cc domes.

[stclark816]

I'm gonna go with a lean condition. Possibly an air leak. What's the other side look like?

[madjimmax]

x2 on being too lean.

[Driggs]

Here's the other side.

 

http://img32.imageshack.us/i/img00007200909261933.jpg

[Driggs]

Lets try that again.

 

http://img268.imageshack.us/img268/1470/img00007200909261933.jpg

[Fullthrottle02]

280's should be good if the bike it stock with just pipes and a filter. What was the cause of the new rebuild, was it just time, or did a hole get blown it one of those pistons as well?

[Coupelx]

definately a air leak. that is preignition at its finest.

[Driggs]

I bought it used, it's a 2006 and it had low compression so I had it bored, new pistons, the whole nine yards. When I first popped the head before the rebuild, the right cylinder head was peppered bad and could tell the owner had put new pistons in but didn’t have it bored.

 

1. What do I look for when I rebuild it so it doesn’t happen again?

 

2. Should I pull the motor and make sure everything is clean in the bottom end?

 

Thanks guys.

[Onesickcrewcab]

I would agree that you had an air leak most likely. Also might want to make sure the float wasn't stuck in your carb and that side was getting fuel.

 

I personally would take the motor apart and inspect.

 

When you put it back together you need to do a leakdown test. If your not sure what that is. Here is a thread for you

http://bansheehq.com/forums/index.php?showtopic=110585

[GrMeyer]

You going to need to split the cases to clean the bottom end. If not then you will in time have the crank fail. It melted for a reason!!! IE listen to people that are putting their .02 in. Im going to have to say that you had an air leak or a float stick. But best of luck.

[sheeman09]

if i had to put my money on something it would be an air leak

[Driggs]

Just to add to this, about 10 - 15 minutes before she died, I took a corner too fast and wrecked the bike. It threw me off and just rolled up on it side bending the handle bars. I wonder if the float got stuck when that happened and caused this. She's been running great before this. Is 10 - 15 minutes enough time to cause this?

[toolman]

Lean X10!!!!!!!!!!!!!!!!!!!!!!!!! always do a leak down test intake leaks are more common than one would think.

 

 

 

Just to add to this, about 10 - 15 minutes before she died, I took a corner too fast and wrecked the bike. It threw me off and just rolled up on it side bending the handle bars. I wonder if the float got stuck when that happened and caused this. She's been running great before this. Is 10 - 15 minutes enough time to cause this?