Re: 1950s Big Twin
Thank you. My next question was going to be about what the compression should be but you answered it.
It's got a funky silver and blue paint job and hardware store numbers on the side but I can deal with that if it's otherwise in decent condition.
100+ psi is certainly ideal, but I wouldn't be too scared if your compression is a little under 100psi in each cylinder, as long as they are withing 10% of each other--if the deal is right. I bought a 35hp big twin with 85 & 90psi... now that it's ran for a bit, the seals have expanded a bit and my psi is over 100 in each cylinder. I've heard people buying them with psi's as low as 65 (not recommended) and still being able to get them to run with minimal effort. But yes, higher psi is better.
With that being said, Zephyr is a much better authority on the subject then I am, he knows his classic OMC's better then just about anyone. I'm just saying if its a smoking deal, but psi is just a touch under 100--it doesn't have to be a deal breaker