Dale_L

Dave,

I have an older YS120SF (bought used) that I would like to get some advice on. The engine does not seem to build pressure in the fuel tank to nearly the level that my 140L does. Is this normal or is it a sign of something else wearing. The tank holds pressure fine for 15m+, so I am pretty sure that I do not have a tank or check valve problem. What else would this be indicative of? I have replaced all the gaskets with Leak Frees, so I do not think that is a problem. Compression seems OK, but would this happen if there were blow-by on the down-stroke by the ring? I do not think I am getting quite the power as others are either when I compare to posts here. I had written that off to high altitude, but maybe it isn't. Anyway, thanks for your time.

Dale

Dave Shadel

The L wiil develop a bit more tank pressure as there are internal changes which the 120 doesn't have. Does your engine run OK?
If it functions properly, just figure that it is an older design engine and just won't make the power of the newer versions.

Dave

Dale_L

OK, thanks Dave, that is what I wanted to know. Now for the mod questions. Would this motor benefit from the piston port mod? What could I expect if I put a NC head with the larger valve on?

Thanks again,

Dale

Dave Shadel

I think you'll spend more $ than it's worth doing this to an old engine. You're looking at $150 plus. Wait for the 140 Sport which is coming out in a couple of months.

Dave