Compression issues

I recently installed an airsal 70cc kit on my 1978 Sachs Westlake. There is spark and gas. However the motor is only making 50 psi. I have no idea at this point what it could be. Any help would be much appreciated!

Also, the piston is facing towards the exhaust port.

Re: Compression issues

Are you opening the throttle when trying to test it? Make sure the choke is off.

Re: Compression issues

How big did you gap the rings?

If you have no manufacture spec it is 0,004 per 1,00 of bore diameter.

Re: Compression issues

Could the wrong spark plug size cause compression loss? The threads should be 3/4" but the one I have is just over half an inch

Re: Compression issues

Not much difference.

Re: Compression issues

How are you testing 50 psi compression with the spark plug in?

> Noah Bachek Wrote:

> -------------------------------------------------------

> Could the wrong spark plug size cause compression loss? The threads

> should be 3/4" but the one I have is just over half an inch

Re: Compression issues

Pushrod Fifty /

Yea good question. Check the orings on your tester.(edited)

Re: Compression issues

I checked everything over 3 times and couldn't find a problem. So I did a test on my go kart and I got the same reading. And my go kart definitely has compression so the tester must be broke. I bought a new one and it made a bit over 90psi.

Re: Compression issues

should be a bit higher but could be tester again. maybe some soapy water sprayed around cylinder and look for bubbles when u crank over. did u cap the decomp or...

Re: Compression issues

Yes, the gas does bubble out of it just a bit. So I got some thread lock for but haven't put it on yet.

Re: Compression issues

It'll start and run at 90. Let er wear those rings in and check it again.

Re: Compression issues

Did you have throttle wide open when testing? Also just keep on kicking it. Should have well over 90. That's just enough to run but barely

Re: Compression issues

most testers today are china made. I don't trust them

Re: Compression issues

> Noah Bachek Wrote:

> -------------------------------------------------------

> Yes, the gas does bubble out of it just a bit. So I got some thread lock

> for but haven't put it on yet.

Exactly where is the gas bubbling out ?

And , where do you think thread locker is needed ?

Re: Compression issues

I wasn't peddling very hard when testing it. So I'm guessing the compression should be fine since it's a new kit. But the kit came with a new decomp plug and gas bubbles out of it. Thread lock should do the trick since it's only a slight leak.

Re: Compression issues

Even the trusted name brand of testers are manufactured in China - or assembled domestically from parts made in China.

> Tri-ped Dave Wrote:

> -------------------------------------------------------

> most testers today are china made. I don't trust them

Re: Compression issues

Pushrod Fifty /

You should do a leak down test of the engine to reveal the leaks. If you search the site you will find endless posts on how to do it.

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