Re: the right compression tester for mopeds<<<<<<<<<<<<<

I'm glad this is helping people. I happen to think static compression is useful performance data. it can be compared to major manufacturer specs to check what is feasible. Most one speeds can handle a little more compression than, for example, a yz. The reason being the bmep is a lot less. I prefer to go high with compression and do the kill switch trick to check for detonation and keep lowering compression until it's under control then replace the 87 with 91 to be safe. But I'd have nowhere to start that line of tuning without this tool. And yeah it helps a lot with checking rings. I've noticed through scouring repair manuals of dirtbikes that the rule of thumb is anything more than a 30% drop in static compression between a wet and dry test and it's new rings time. I've noticed that an engine will burp with rings that bleed more than that(fuel in the crank case will light off)

Re: the right compression tester for mopeds<<<<<<<<<<<<<

i'm pretty sure my valve is right by the part that screws into the plug hole. a stock ciao made 90psi with it. sounds right, right?

Re: the right compression tester for mopeds<<<<<<<<<<<<<

matt boda1nz /

I got 145 psi on stock qt50. fresh kit that hadn't been ran but 10 minutes.

I had 80-90 on a tester that didn't have two valves.

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