915 Gearbox Assembly

Steffen

This is what heavy maintenance is for.  If you have not the experience then the book is only a reference.  I can't see why anyone would take this out and play with the alignment.  The dogs have to engage fully in depth for the friction clutches to damp the torsion shaft windup in engine starting and shut off.  The gearbox noise you hear is the back and forth movement of the main gear with overload clutch to the intermede clutches (there are 2) The key part is the master spline edge in relation to the dog as shown in the picture. 

I would suggest you contact Franz, the Rotax distributor in Germany, for a better understanding.  If you do not have the right parts it may be you will need to sent the gearbox to them.

Best of luck.

Cheers

We only did remove the gear from the engine, which surely is line maintenance, not heavy.

and we did not change the alignment, turned any clutch or anything else, just put them back on the shaft as described in the manuals.

This is totally line maintenance.

We will bring the gear to Franz and will oversee what they do, because there is no chance to accept any discussion about the classification of line maintenance for this work, so they have - as we well know from Rotax Austria - the duty to teach everything in the lmm.

to your picture: I don‘t know hat the index should have to do with our situation. This index is aligned of course. Shall the dog be aligned to that!

Still the question, how do the dogs have to be? Aligned or engaged?

Hi Steffen

OK my last word.  The dogs "engage" each other.  Given it is a tight tolerance the tool shown in the manual is to twist the torsion shaft to get them to drop into place.  As the twist is applied a bump with a soft hammer may be needed downward while you apply force to the gear via the tool as shown in the manual.  

Please contact your service trainer and they can explain this to you.  Not all torsion shaft and gear sets will require this but it is common practice with the 915 and 916 to have to do this if the gear comes off the spline. 

Cheers