I know I'm going to hate myself for getting involved in this. There is no
motorcycle engine out there that has even a passing resemblance to the Rotax
912. Even if there were a motorcycle, car, hot rod engine operates at a
small fraction of it's rated output except for short bursts. Typically a
motorcycle engine of 1/2 the displacement of the 912 will put out up to
1.75X the horsepower so the whole design philosophy is different. Outboard
boat motors live a similar life, long periods of high output at a steady RPM
and they also don't crank out quite the HP per CC as motorcycle engines.
I would put the service bulletins put out by Rotax down to the company
trying to provide the best support they can based on the knowledge gained by
field service. I hate to give them any credit because I think they are way
overpriced, but they are doing an exceptional job of support.
Back to Rotax recommendations for heat sink compound. Anti seize grease (I
use the silver kind) is not a heat conductor and is likely not the proper
choice. I can't tell what CPS sells, but Leaf sells a Zinc/silicone product
from MDG Chemicals. If you choose to use a non-rotax heat sink paste it will
likely offer a pretty good anti seize property from the zinc and I would not
discount the knowledge that CPS, Lockwood and LEAF bring to the field. Their
aftermarket choices are probably pretty good.
So, IMHO you are not bound to use only Rotax products, there are cheaper
alternatives. But seeing as you are operating an aircraft, choose carefully.
Do not archive
----- Original Message -----
From: "Av8r3400" <theav8rweb@yahoo.com>
To: <kitfox-list@matronics.com>
Sent: Wednesday, November 18, 2009 1:05 PM
Subject: Re: Rotax spark plugs
>
> Isn't it a fact that the majority of the reams of service bulletins on
> these engines (900 series) and their associated (ever changing)
> maintenance requirements, stem from the military use of these engines in
> the Predator drones, operating at 120+ hp, 40k thousand feet, for 20, 30
> and 40+ hour missions?
>
>
> How many million motorcycle engines (What the 900 series is based on, with
> aluminum heads and NGK spark plugs) without the need for $300 heat-sink
> paste on their threads?
>
