blown banshee

[chevyeatr]

Hi all, I blew my banshee up thanksgiving weekend at dumont and was wandering if i could get some help? I burned holes in the top of both pistons. The top end was just rebuilt and only had 1 tank through it. Also are all the stock cylinder heads the same?

[[email protected]]

Hi all, I blew my banshee up thanksgiving weekend at dumont and was wandering if i could get some help? I burned holes in the top of both pistons. The top end was just rebuilt and only had 1 tank through it. Also are all the stock cylinder heads the same?

 

sounds like you ran lean and OH NO bab ab abaoom, time to start over

[dajogejr]

Stock heads SHOULD be the same, but I've seen the dome cc vary from 22 to 24, to be honest.

 

Start with a list of all your mods...and your current jetting.

Both pistons? Wow...usually one goes before the other. Time to tear it all down, check the crank, bearings, etc...

 

Possibly air leak, lack of octane or lean jetting....

[chevyeatr]

Stock heads SHOULD be the same, but I've seen the dome cc vary from 22 to 24, to be honest.

 

Start with a list of all your mods...and your current jetting.

Both pistons? Wow...usually one goes before the other. Time to tear it all down, check the crank, bearings, etc...

 

Possibly air leak, lack of octane or lean jetting....

The banshee is stock other than the 2 into 1 carb set up. The reason i asked about the heads is because the head that was on the bike originally had a deeper dish than the 1 i put back on the bike when i rebuilt it. So i'm wandering if that had something to do with it blowing up?Anyways thanks for the info guys , I'm gonna pull the engine and completly go through it so maybe i will just get a cool head for it.

[wacko2000]

Sorry to hear about your bike, sucks that it was just rebuilt, but on a better note, now you have an excuse to make her Faster...

good luck dude...

[Washburn]

The banshee is stock other than the 2 into 1 carb set up. The reason i asked about the heads is because the head that was on the bike originally had a deeper dish than the 1 i put back on the bike when i rebuilt it. So i'm wandering if that had something to do with it blowing up?Anyways thanks for the info guys , I'm gonna pull the engine and completly go through it so maybe i will just get a cool head for it.

 

No adding more or less compression without porting,new pistons diffrent crank/longrods ect.. has very little to do with a richer or leaner running motor. Reeds on the other hand could make you run a little fatter in the mid say if you installed VF3s to stock. There is always the case that when you put the head on you put a bad head gasket on or forgot to put it in before you instaled the head witch could definatly cause that. Also if your running in these freezing conditions we just got here and dident change your jetting theres your problem.

[rubberneck]

No adding more or less compression without porting,new pistons diffrent crank/longrods ect.. has very little to do with a richer or leaner running motor. Reeds on the other hand could make you run a little fatter in the mid say if you installed VF3s to stock. There is always the case that when you put the head on you put a bad head gasket on or forgot to put it in before you instaled the head witch could definatly cause that. Also if your running in these freezing conditions we just got here and dident change your jetting theres your problem.

 

True, changing compression has minimal effect on jetting requirements, however it sounds like the head he put on may have been shaved. Using his terminology, the original head had a "deeper dish" than the new one. By putting the smaller CC head on he may have increased the compression to the point of needing to run higher octane fuel. Was the bike "pinging" before it blew up. What octane fuel were you running? What is your timing set at? Detonation can kill a motor even if properly jetted in a heartbeat.