Leakdown and compression

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davesax36

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Is it possible to do a leak down test that shows less than 4% loss, and still have top end issues?

My leak tester is reading 88 psi in and 86 psi out on all cylinders. Cylinder 3 plug looks rich, but not soaked, and I'm getting 20mpg. I'm very concerned about gas washing that cylinder and am wondering if redoing the compression test with a couple drops of oil in the cylinders is worth it due to my leak test results.

At the end of a ride I'll usually have a wet carb body #3 between the air box and v-boost rubber. A friend of mine is saying it sounds like a clogged air bleed somewhere that's loading at cruising rpm, but doesn't act weird at idle. I want to get this figured out and run a couple more tanks through it before the motor comes out. It's already been pushed back too far.

Thanks, guys.

Sent from my Galaxy Nexus using Tapatalk 2
 
A compression or cylinder leakage test will help identify any issues with piston ring or valve seat sealing.
It won't help with incorrect fuelling.

I would start by checking that the air filter is clean.
Then check float heights.
If they are OK strip, clean and inspect the float needles.
 
The leakdown tells you your top end is healthy, or not. Fueling should be better than 22 mpg in a stock engine. W/stage 7 & a 4/1, my bike doesn't do much better than that in stop & go traffic, but I got 34 mpg highway in Daytona, last time I checked.

Your stock settings for the carbs should be checked as was mentioned. Yes a poorly-sealing needle valve & too-high float setting will cost you mileage.
 

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