aprilia rs 125 rotax 122 main bearing replacement running in

[merky69]

ok so ive done a couple of these main bearing jobs before on the rotax 122, but today i got the crank out of this 122 engine and there was a big washer behind the bearing, is this supposed to be there ive never seen this before on any other rotax 122, could this be the reason for the bearing goin early on the flywheel side as the bearing the clutch side is fine? im baffled and would like help pleeeaasssee before i put the new bearings in.

also does anyone know the correct running in procedure for a rs that has had new main bearings

thanks fiorl ooking any help would be greatly appreciated .

[bikenut]

any pics as well as exploded views from a parts list??

may be to control end float but you have had these engines apart before and this washer is not the norm??

was crank shaft tight and not easy to turn before main bearing "went"................

what is end float arrangement tother end of crank, drive end.......?

gear primary drive, double helical?? ( like citroen car sign ) pics might help.
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nuts about bikes

[prawny1]

Was the washer between the crank and the bearing or between the bearing and the seal?

It would be strange for it the be between the bearing and seal, as that could reduce oil flow up through the bearing transfer port.

The crank can be shimmed on either side between the crank and bearings to keep the crank central in the crankcase and to stop it shifting side to side (end float).

Maybe the old crank had been pressed together a little narrow and had to be shimmed out.
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hellkat wrote:

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[merky69]

[Calum122]

To clear the matter, these are clearance washers used to ensure the the bearing sits true in the race.


https://i.postimg.cc/FzTJ6RMB/Washer-axial-clearance.png

They are known to come in one or two sizes depending on the clearances needed. So don't mix them up, or re-measure the tolerances when rebuilding.[/img]
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[Nobby the Bastard]

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