How to make a 2 stroke leak down tester

[sandblaster]

How to make a 2 stroke leak down tester
All these pics and info were donated by Motorrad.

Crank seals are meant to seal pressure... but they also are exposed to vacuum in a 2T motor.     and thus.. the way they are designed.. will show problems under vacuum that wont show up in pressure test..    Pressure test is ONLY good for finding gaskets leaks (In my humble opinion)....

Needless to say.. I test both.

when I get done with a K5 motor.. it will hold 7psi overnight.

so..
Items I use

1 3/4  plug
2  1/4 Plug  (had to shave it down some in lathe... could do by hand with a grinder too I guess)..
Old spark plug with innards busted out.   and a .25 barb.   soldered together.

the reason I used that barb.... is I have a VERY accurate Bicycle pump. (wife races)   that reads low pressure well,   so the shrader end will seal against it.   as also my hand vacuum pump hose goes right on it..  so I can swap between pressure and vacuum easy.









So easy a kid could do it  

[Charlie500]

that's a clean looking k5! where do you put the plug? can you post up more pics of the process?

[Charlie500]

nevermind, the plug goes in the exhaust!!! i'm a big dummie...

[sandblaster]

I don't have more pics but one plug goes in your carb boot, the other goes in your exhaust outlet.
Then you screw in the spark plug adapter.
That's where you pump in positive or negative pressure.

http://www.youtube.com/watch?v=zdq7NRcUIp8

He neglects to use vacuum in this video....
Also keep the pressure at about 7 lb, not the 9 he recommends.
This will give you a better idea.

[sandblaster]

nevermind, the plug goes in the exhaust!!! i'm a big dummie...

Too late 

[Charlie500]

My company blocked youtube from us.... I'll have to check it out when I get home on the 22nd... I'm definitely going to try it... I gotta make sure those seals aren't leaking...

[sandblaster]

Good idea