Proper compression (Cyclone 340)

[rmreid]

Hi,
What is considered good compression on a 76 Cyclone 340? I have 120psi on both cylinders but I did not have the throttle wide open when pulling. Will do that tomorrow, ran out of daylight.

Thanks for any information.

Randy

[S_Kyle]

120 is great if it is the same on both sides. I think they should be 110+ and with in 5 psi between the cylinders. I have been told 5 pulls with the throttle wide open and some say go till the gauge maxes out.

I haven't had much to do with the Cyclone but most of my Liquifires run around 123 psi or so.

[harleysportster]

A fresh rebuild with the proper clearances for the '76 series Cyclone engines will yield 135 to 145 lbs of compression. As stated, 120 is still good as long as the cylinders are 10 lbs within each other. There is no magic number of pulls of the recoil but the throttle level must be wide open. Generally, you turn the engine over until the highest number is reached. If you have electric start, you may use it.

[rmreid]

Thanks for the information. Did a thorough compression test today. Throttle wide open, 5 pulls on each cylinder. Results= 130 on #2 cylinder and 132 on #1 cylinder.

I gather from the information that I have good compression. Thanks again.


Randy