Another thing that might make his .65 feel like there's no compression is a "dry" cylinder. If it hasn't been run, or hasn't been run in a while, theere may not be enough residual oil around the rings to help the compression seal. I've noticed that when one of my Saitos sits for a while, it feels the same way; after I turn it over a few times, or run it, the compression gets much better.
While I'm on the subject of Saitos
, an update and couple of questions on my new 1.00. I've got a total of 5 12 oz. tanks through it now, total run time about 1-1/4 hours. The last two have been with a 15-8 prop, and the needles reset to where they were out of the box. It is running much smoother, and I treied peaking it out yesterday. The most rpm I can get with the 15-8 is about 8400, and the needle is about 2-1/4 turns out when it peaks, so i richen it to about 3 turns or so, rpms about 8250, and a visible smoke from the exhaust, but not overly so. I leaned the low end down to about 3-1/4 turns, and I can get a reliable idle (it will run as long as I leave it, with no splutter or stall) at about 2150. The transition throughout the throttle range is good, whether I goose it quickly or gradually, with just a tiny stumble coming off idle (it's a rich stumble, there's more smoke for a second). I am happy with the response, but have two questions:
1- All the rest of my Saitos have much less turns out on both needles (Usually around 1-1/2 to 1-3/4 on the high end, and about 2 on the low end) Why the big difference? Is it just the amount of run time on the engine compared to the others?
2- Top rpm--I'd like to get the engine at WOT to turn in the mid- 9's. I've already found that a 14-6 is too small (turns way over 10K), and the 15-8 is appearing to be a bit much. Would a 14-8 or a 15-6 be the better one to try? I really don't care about more speed, what I'd like is better vertical. I use the MA-K series, I don't care for APC props, but I occasionally use Zingers