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View Full Version : 350pv leakdown question



SuperSherman
06-15-2010, 07:58 PM
Last weekend I took her out for the first time in a while. If I pulled the clutch in midrange and let off the throttle it reved pretty bad, but only in the mid. After a bigger main and a clip positon change fatter, it still did it. Airleak was my first guess and so I checked it today to find that the vent tube was the only thing leaking. Is it supposed to? That tube isn't supposed to be plumbed into anything right?

Jonny B
06-15-2010, 08:19 PM
How did you do the leak test??? A leak test will test the sealing of the top and bottom end on a 2 stroke. The engine needs to hold 6 ft lbs for 6 minutes. The tranny is seperate from these and should be vented to relieve case pressure...

SuperSherman
06-16-2010, 06:53 PM
Soft plugs in the intake and exhaust, 9lb through the spark plug hole. If I plug off the PV vent tube, it will hold pressure just fine.

fearlessfred
06-16-2010, 07:10 PM
prob.clutch side main seal leaking

bloodswet&gears
06-16-2010, 07:42 PM
nothing should come out of the vent tube during a pressure test.
if you have access to a smoke machine, you can blow smoke in where you were pumping air in. where the smoke comes out is where its leaking.
if you dont have a smoke machine, you can use soapy water and watch for bubbles.
its easier to pinpoint with smoke.

bloodswet&gears
06-16-2010, 07:48 PM
sorry, i missed the pv infront of the word vent. im not sure on the pv vent. nothing should come from the crank case vent.
sorry

fearlessfred
06-16-2010, 08:06 PM
unless the crank mainseal is leaking on the clutch side

SuperSherman
06-17-2010, 04:12 PM
There is absolutely no leak anywhere but the PV vent. Is it supposed to leak?

hartwill
06-17-2010, 04:37 PM
t

fearlessfred
06-17-2010, 04:39 PM
im not sure what u are calling pv vent , the vent below the carb that comes out of the trans. if so that would indicate that clutch side main seal is leaking or the center case gasket is blown (but i have never seen that happen before) as blood sweat and tears allready said NOTHING should be coming out of any wear

Aceman
06-17-2010, 09:42 PM
Could your throttle be sticking? Does your slide move freely?