Microlighters

How do you change the bearings on a 503

Willie

Read Rudi's thread on overhauling his 503. It uses a split crank with 5 main bearings. You can get the outer 3 from the agents, pull them off, and replace. (2 On one side, one on the other.)

The problem comes with the 2 centre main bearings as well as the big ends on the connecting rods. To replace these, you need to split the crank. Rotax does not recommend this, and as far as I can tell, do not sell these bearings. You need to replace the complete crank, according to Rotax, every 300 hrs. (Somewhat costly. I don't know if you get anything in return for your old crank in SA, you certainly do in the US.)

The small ends are needle rollers that are readily available, and easy to replace.

Options (I'm not recommending this, merely stating options you may consider):

Have the bearings checked and re-certified by a reputable company.

I have often heard of guys replacing just the outer bearings, as they are the ones working the hardest.

One may consider a combination of the above, re-certify the inner 2 plus the big ends, and replace the outer 3.

Barry

Thanks Barry
Friend of mine is replacing the crank because the bearings needs replacement and I thought maybe if the crank can be split like some motorbike engines. What does the exchange cost where you are
It maybe a option to DHL one from there.
Regards
Willie