Rotax engine - where to get maintenance info?

[Dave S]

Tim,

You do not have to subscribe to get the engine manuals.

Click on the link Larry provided

Go to the top of the page and select support/bulletins - go to engine manuals - you can download (or open and save to your computer) as many of the PDF manuals as you want...its free.

DS

[TahoeTim]

I understand the free areas and thank you.

I meant to ask if anyone subscribes to the site to get the extra goodies. Is that worth the $30. I may do it for one year.

[Dave S]

Tim,

Sorry...misunderstood your question

DS

[jrevens]

I believe he's talking about the ring mount to engine, Eddie. The torque value for those 4 bolts can be found in the parts manual - 30 Ft. lbs.

Those plated, steel bolts are mated with tapped holes into aluminum. In my opinion, it is good practice to lightly coat the threads with anti-seize compound to help prevent any galling or corrosion

[jrevens]

I believe he's talking about the ring mount to engine, Eddie. The torque value for those 4 bolts can be found in the parts manual - 30 Ft. lbs.

Those plated, steel bolts are mated with tapped holes into aluminum. In my opinion, it is good practice to lightly coat the threads with anti-seize compound to help prevent any galling or corrosion

Dave’s comments about Rotax recommended torque values are exactly right... don’t know why they had to make it so hard to find in the past, or why they changed. The value I mentioned above (30 ft. lbs.) was directly out of the parts manual only a few years ago when they used to publish many torque values there (Section 71-20-00, p.3). They have obviously changed the recommendation since then and Dave’s info is correct & accurate, as usual. Use the standard values listed in the current Heavy Maintenance Manual (28.5 ft. lbs.). I’m sorry to have added any confusion to the conversation.

As far as using anti-seize, Jim is absolutely correct (as usual also!). I still personally think it’s a good idea in this situation, and I believe it was also recommended to me by Kitfox. I’ve seen adverse results of steel bolts in aluminum multiple times over the years when doing engine work. I think it’s unlikely there would be any adverse over-torque, especially since there were thousands of engines probably using the higher published torque value for years, and it is now lower to begin with. As always, these are just my personal thoughts and people have to make up their own minds.

[Dave S]

John,

There is a very small difference between 30 and 28.5 foot pounds - that difference is so slight that it is insignificant considering the pitch of the threads and the diameter of the bolts.

As you mentioned, Rotax has changed a number of their specs - all very minor - such as the spark plugs were 177 inch pounds (cold) once and now it is 180 inch pounds (cold) - again insignificant differences. Then there are the cylinder head nuts - once a specific torque was given and now they list a lower torque followed by a specific number of degrees rotation after - my guess is the final results are pretty similar.

If a person looks at the small differences as a percentage change rather than an absolute amount, it is easy to realize that other factors affecting torque are probably larger (wrench calibration, temperature of the parts, differences in condition of the thread surface.) We try to measure what we can to get as close as possible and then accept, by necessity, that absolute precision is a near impossibility.

In the end, we are all good.

[Peteohms]

I understand the free areas and thank you.

I meant to ask if anyone subscribes to the site to get the extra goodies. Is that worth the $30. I may do it for one year.

I subscribe. Very useful videos.

[jiott]

I subscribed for one year and found it very useful. Its nice to watch a video the first time you do a carb sync, a compression test, an oil purge, etc. After that first year I dropped it.

[TahoeTim]

that's my plan

thanks everyone

[jiott]

Most torque values, unless specified otherwise, are for dry threads (no lubrication). Anti-seize compound will act as a lubricant, which may cause an overtorque situation if you use the same torque value. I don't know if this is very significant or not, but I bring it up anyway because some folks may not pay any attention or realize that a torque spec always includes a "dry" or "lubed" condition.