View Single Post
Old 07-21-2014, 03:47 PM   #12
Dave R
Senior Member
 
Dave R's Avatar
 
Join Date: Jul 2004
Posts: 2,974
Thanks: 246
Thanked 736 Times in 438 Posts
Default

Quote:
Originally Posted by polarisman14 View Post
I have already gone through and replaced all of the hoses on the engine with higher quality fuel line grade ones and new worm drive clamps. I have the carb rebuild kit and fuel pump diaphragm to put in (just haven't had any time--2 weeks til' I'm a dad!) and then I'll look into the crank seals if necessary. I know ripping a 2-stroke engine down isn't difficult and if I go that far with it I'll get new rings and whatnot to freshen everything up. I don't know that the crank seals are necessary though, provided a leakdown test would sufficiently check for that. I did a leakdown test and with 100psi in I got 96 out for a 4% leakdown in each cylinder--that's pretty low especially for something that old so I was pleased to see that.
Cranks seals can't be tested with a normal 2 gauge leakdown tester. They seal the crankcase from drawing excess air in around the crankshaft when the crankcase has a vacuum. You want 100% of the air to come in through the carbs with no other route possible.

A normal leak down test is not very useful on a two stroke as it can only test the rings.

Here's a great link about two stroke pressure testing: http://www.klemmvintage.com/airleaks.htm

Congrats in advance on becoming a dad! I'm approaching empty nest status rapidly...
Dave R is offline   Reply With Quote
The Following User Says Thank You to Dave R For This Useful Post: