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B50 MX Gearbox Mainshaft Bearing 70-8151

Posted: Sat Nov 21, 2020 11:31 pm
by petergj
Can someone help please. I am trying to change the Gearbox Mainshaft Bearing 70-8151 within the timing cover on my B50 MX. I was expecting to find this bearing held in place with a circlip (70-8152) but it is located by a retaining ring (see photo).
20201121_214915.jpg
Can someone advise how to remove the snap ring - it has so far defeated me!
Thanks in advance for any information.
Regards,

Re: B50 MX Gearbox Mainshaft Bearing 70-8151

Posted: Sun Nov 22, 2020 6:01 am
by Momus
Drill a 3mm hole beside one end so you can get a pick under it.

Re: B50 MX Gearbox Mainshaft Bearing 70-8151

Posted: Sun Nov 22, 2020 4:50 pm
by minetymenace
If you use a mm drill on your bike a BSA fairy will die, please use 1/8 inch. :ban

Re: B50 MX Gearbox Mainshaft Bearing 70-8151

Posted: Mon Nov 23, 2020 2:09 pm
by petergj
Thank you for your comments.
I eventually managed to remove the retaining ring - I was expecting it to have a round cross section but it was flat. Anyway, a new retaining ring has been ordered and I hope it will be a proper circlip!
Thanks again.

Re: B50 MX Gearbox Mainshaft Bearing 70-8151

Posted: Mon Nov 23, 2020 5:42 pm
by Momus
petergj wrote: Mon Nov 23, 2020 2:09 pm Thank you for your comments.
I eventually managed to remove the retaining ring - I was expecting it to have a round cross section but it was flat. Anyway, a new retaining ring has been ordered and I hope it will be a proper circlip!
Thanks again.
You dont have to hope; circlips are standard dimension hardware items and readily available from bearing suppliers in various styles.

Low profile bore clips like that are often fitted for a shaft clearance reason, not just to inconvenience you ;-)