Originally Posted by lbz34

.12 Nova 353 steel bearing. First 1/4 of a gallon ran good rich for break in. Problems started this last weekend. Stock settings are 5 turns on HS and 2.5 on low side. Motor wont clean out at all with more than 2.5 turns on the top side. The biggest problem I am having is the low side. When the motor comes off the top end the idle hangs, seems lean, took the low side out to4.5 turns and still does it. Idles fine all day, of idle it bogs like it is rich. On a 2010 worlds car with 3 races, no tank leaks, new fuel line.

Today I took the motor down and cleaned and reassembled it. Seems to have some air drawing through the front bearing. Nothing else is leaking any air, but the front bearing seems to pass a lot of air if I pull vacuum through it. Bearing is still smooth as can be but this hanging idle is chapping my ass.

I guess maybe try a new front crank bearing? Any other ideas? Ran fine first time out with the needles stock but leaned enough to get around the track. Now have the hanging RPM problem. Come off of full throttle and the RPM hangs for a long time.

Did a smoke test and only get smoke through the front bearing, very hard to blow any air out through it, but I can draw quite a bit of air through the crankshaft if I draw vacuum.

Any help is greatly appreciated.