What brand is your compression gauge? Is it accurate? We’ve seen plenty of gauges not give a correct reading. We've purchased brand new gauges that would just stop at a certain PSI and not go any higher, no matter what the dome size. The only brand that we have found to be consistent is Snap-On. Generally the gauge itself may be fine, but the connecting hose may be old and too soft, giving too much flex.
When we check the compression we leave the spark plug in the other cylinder not being check, with the plug cap off, and hold the throttle wide open on a freshly charged battery.
Is your cylinder ported? Are you using the stock thickness base gasket? What elevation are you at?
All of the compression readings on our website are on a stock non-ported cylinder and at sea level elevation. Thicker base gasket lowers compression. Raising the exhaust port height, increased opening duration, lowers compression. Increase in elevation also lowers compression.
There are many variables when it comes to compression. Don't always trust the gauge.Copyright ADA Racing. All Rights Reserved.
