PDA

View Full Version : need help



no limit
05-01-2005, 08:56 PM
my ex was just rebuilt about 3 weeks ago, it got a 440 12.5-1 piston, head porting, and a stage one hot cam. it has run great ever since, but all of a sudden it makes this loud knock under load. it doesnt sound like a ping, its way louder and sounds like a hammer on the side of the cyl. i thought maybe it was a ping so i added some 100LL av. gas to premium and it still does it. ive adjusted the valves, tried different fuels, but it still does it. it only does it when you are about half throttle and punch it, it doesnt do it when you lug it or rev it just at the time you punch from about half throttle. its really loud- other people riding with me can also hear it. any ideas on what this is or how to make it go away?

no limit
05-03-2005, 12:45 PM
...

SHARPMACHINE
05-04-2005, 05:43 AM
It sure don't sound good.

I would put a breaker bar on the crank and move it back and forth while listening for a rattle or noise.

Also use a hose as a stethascope to try to find it while it is running, hopefully it is a vibration or something.

good luck