Comment

Comment by Chris Aysen on July 8, 2010 at 7:33am

Pat - I have talked to a couple of racecar engine specialist. They said the cheapest way to make your engine more efficient is port polishing; exhaust and intake. Their reasoning is your exhaust manifold (and/or intake) may not match up exactly with their perspective mating parts. Therefore, you may have some flat spots in, for instance,the exhaust tube that create turbulence somewhat restricting exhaust flow. I believe gaining 5 - 10 HP is somewhat obtimistic. It would be more probable that any particular factory engine would have some flat spots restricting airflow and port polishing would bring you UP TO advertized hp.. So we may be running our engines up to rpm and not quite getting advertized hp. But I do believe port polishing would produce gain in engine efficiency not necessarily more than advertized hp.

Comment by Mike Ethridge on July 5, 2010 at 3:48am

Bob I'm seriously thinking about the Bully Hawk 914 conversion from LES for my 912ul since they reduced their price from over 12,500.00 to around 8,500.00 dollars a few months back. I like the extra horsepower, light weight and stable operating temps of this engine which make it a good option for the CH750 and I would think a good resale point for anyone looking at amfib floats. Still looking at options but keep coming back to the tried and true stuff. Mike

Comment by Bob McDonald on June 29, 2010 at 7:49am

Contact Bob Robertson of Light Engine Services in Salmon Arm B.C. 1-866-418-4164.
There is also another advertised (no experience with this one) google "Rotax 912 X-tra" its a power boost kit involving pistons and exhausts. Generally Rotax has enough expertise on their engines that your not going to gain anything over factory product. Remember if you change the exhaust...you probably need to adjust carburation or air intakes. More power usually results in reduced reliability...its a balancing act.
When it come to Rotax Bob Robertson's the go to guy...I strongly recommend his advice be followed.