Gearset replacement

It depends on the amount of wear on the dog hub. The propeller shaft and bevel washers are also often replaced and if the prop shaft is pressed out, the bearing and oil seal needs to be replaced. During re-assembly, It's important to have the gearbox properly shimmed or it will chatter and rattle and cause premature wear. 

In all honesty, if you haven't done this work before, it's best to send the gearbox to a Rotax repair or service center and have them do the work as they have the proper tooling and experience. 

I agree with Rotax Owner post. You need some experience or training. The consequences could be expensive.

Hi. Thanks for the replies. The work is going to be done by an automotive mechanic who is also experienced with Rotax engines. If too much wear on the small doghub is discovered I envisage having the gearbox reinstalled with the new gearset only. I would order a new doghub for installation on a future occasion - or could that cause harm? ?