crankcase vent or air leak?

[lancerg89]

i have a 01 blaster that i cant seem to get running right. it will run fine with the choke out but once pushed in it revs out of control. i cleaned the carb several times with no change and i did a compression test and it stays at 100 psi. next i did a leak down test and found air to be coming out a lil nipple right under the rubber intake manifold and on top the crankcase? once i put my finger over the nipple air then leaked right under the carb where the cases meet? do i need to do a bottom end rebuild or is this nipple being open causing me to run lean and reving out of control or do i have a winter rebuild project? any help would be great I:I

 

[1995blaster]

Its the crank seal on the clutch side is bad, they are under 10 bucks on ebay. Or it could be a crack in the case but i dought that. Replace then re leak down test.

 

[brandoz28]

either the crank seal or a leak between the halves. check the stator side too

 

[Blaner]

the vent leads into the transmission section of the motor so if its leaking out there, it means your crankcase is leaking into the transmission and vice versa...like all have said, eithere crank seals or case halves leak..either way, its a bottom end job for you!

 

[Blaaster]

If it is only a crank seal it can be replaced without splitting the cases.

If it is a leaky case you will have to split them.

 

[lancerg89]

well thanks everyone. im confused tho the air comes right out of the vent but the case don't leak till i hit about 10 psi with the leakdown test and with my finger covering the vent

 

[Blaaster]

Crank case shaft seal seems to be the culprit.

Dont pressurise it more tha 7psi you could blow the other seal!

Read the post wrong, if it is holding at 7psi its prolly still ok.