View Full Version : removing rotax gearbox

profqwerty - n/a
7-Sep-07, 09:55 AM

I've got the gearbox off and the crankshaft bolt out...but the gear on the crankshaft just isn't coming off.

I'm replacing the small gear with a flexy coupling flange, so i'm assuming there's a taper on the gear as well.

Is there any way of getting the gear off? or do i have to fork out for a gear puller?

I'm not sure how far i can go with it without damaging something (like hitting it etc).

Also anyone interested in a roatx "A" gearbox + mounting adapter? I believe the gears are the 1:2.58 set.



peterd51 - n/a
7-Sep-07, 11:35 AM

although I'm not familiar with the specific engine/box...

in general if you have access to both sides of the gear then you could lightly tap both sides simultaneously with two hammers, ie, if the gear was a clock face then you tap it at 9 & 3 o'clock, etc.

This will generally pop a gear/pinion, etc, off a tapered shaft.

Other than that, could you apply heat?



hovmart - n/a
7-Sep-07, 11:39 AM
there is a rotax extractor tool but they are not cheap, if you were nearer you could borrow it

jon_curtis - n/a
10-Sep-07, 10:04 AM
dont start hitting anything with a hammer and certainly dont put any heat on it, as it will melt the oil seal!

the inside of the gear has a taper yes! Sometimes loctite is used on the taper, it shouldnt but i have spoken to rotax service engineers, that do and dont put loctite on the taper!

a gear puller will get it off, however as mentioned there is a specific tool for extracting! this screws into the gear and has a large set screw down the middle, which when tightened pops the gear off!

if you can get to someone like ken @ K&M, or skydrive/conair they will all have the tools, i used to go to the local flying club, where a helpfull rotax guy popped the gear off in less than 5 secs, where i have been messing with stupid 3 legged pullers for hours!

profqwerty - n/a
10-Sep-07, 10:33 AM
I have started ti fashion my own gear puller (only had an hour this weekend!).

It's a strip of steel 5mm thick, and i have ground down one side to let it fit between the gear and the casing (not the oil seal - this is recessed). it's not perfected yet (i.e. not thin enough), but seems to be promising.

i saw the thread inside the gear, but unfotunately don't have anything to fit it. I don't have a lot of free time at the moment (6 days a week teaching engineering!!)but i might try getting to White Waltham.

they have a (big) gear puller here where i work - but it's claws won't fit behind the rotax gear!!!