no compression cyl 1&2 912 ULS

[turboturner]

Thnx for the feedback DeeDub, Jim & John. I appreciate the « food for thought » & like where this thread is headed. More comments welcome!

[jiott]

John, I sure am curious about the source of the 5400 rpm recommendation. I find nothing in the Rotax Operator's Manual except an operating range.
Yes I did the recommended gearbox removal/inspection/service at about950 hours-sent it to LEAF. They reported it was in very good condition, clean and only replaced the usual springs and washers (I use nearly 100% mogas clear). It never showed any unusual backlash, however I didn't measure it, or any unusual starting kickback or noises. My prop is ground adjustable, set to slightly favor cruise speed, so it is loaded fairly well at my 5200 rpm cruise.
I find that the gain in speed from 5200 to 5400 rpm is a minimal 2-3 mph and an increase in fuel consumption of about 0.5 gph-not worth it IMHO.

[jrevens]

Makes sense to me… thanks Jim! I don’t believe any of the talk and opinions about it that I’ve heard have come directly from Rotax.