compression testing

Ive got some running mopeds but how does one go about testing their compression?

Re: compression testing

Thread in the tester, hold the throttle grip WOT and kick it over a few times.

Re: compression testing

into the spark plug hole right? WOT? is a tester costly?

Re: compression testing

Yes, it threads right into the spark plug hole. Mopeds have a 14mm spark plug hole. "Wot" is wide open throttle. I think sears or most auto parts places have ones around $25-30. You could probably find them cheaper if you search around. There are two types, a thread in and a push in type. The thread in type is best.

Re: compression testing

will it also gauge top dead center?

Re: compression testing

no

Re: compression testing

Re: compression testing

Ben Van Zoest /

You could buy or borrow one like this!

1190034272_compression_tester.jpg

Re: compression testing

can someone please explain why you are suppose to hold the throttle wide open?

people say this all day long, but it makes absolutely no difference in the final reading

Re: compression testing

I would think to make sure your getting fuel in there to make a nice seal with the oil?

Re: compression testing

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