Hitchcocks Forum

Hi Guys

Do you any tips for dropping mainshaft bearing in gearbox clipper/bullet 350 using basic tools ?
please advise

Regards
ET

If you have the gearbox off and apart, sticking the whole thing in the oven for half an hour will most likely see the bearing fall out by itself.

Replacement would be similar but also put the bearing in the freezer too overnight. It should them tap into hot cases using a suitable size drift against the outer race (a big socket).

Michael Waller is doing a series of videos building a bullet trials bike just now. He goes into detail about the gearbox rebuild in detail. I think this is the one he fits the bearings in. He has a hydraulic press (and if you have one, there's no good reason not to use that) but with a hot case and a cold bearing, it'll probably go most of the way in by itself, won't take much force to drift it the rest of the way.
https://youtu.be/baK5q9hv6Iw

Ignore him fitting the gear clusters, he makes a right hash of it. It's a fairly straightforward job.

stinkwheel wrote: ↑

Fri Nov 29, 2019 1:01 pm

https://youtu.be/baK5q9hv6Iw

Ignore him fitting the gear clusters, he makes a right hash of it. It's a fairly straightforward job.

He gets it right in episode 18 though:
https://www.youtube.com/watch?v=FYN5b0Ut6D8

Frank

Thanks for yr advise i have question gearbox back end have narrow opening thinking so if i put seal in hot casing it might it can be melted ?

I have to put oil seal and washer first then bearing in the casing right ?

Thanks

Well, the gearbox gets quite hot in use. If the seal is neoprene it will be fine up to about 120c which will give you a bit of clearance. Viton seals will go even hotter.

All rubber/nitrile/viton/silicone oil seals are rated to at least 250C in normal operation. Many will go even hotter.

EDIT: Neoprene is rated to up to 275C

Thanks PeterF, Stinkwheel for your quick feedback. appreciate your help for newbie.
this question i cannot get rid from yesterday. ..

i can use indian gearbox mainshaft seal into english gearbox. ?
sorry going bit offtopic

This isn't a conversion I have done (has anyone?) but the best way forward is to measure up the casing and the seal and if they don't match, first ask Hitchcocks. Or just ask Hitchcocks first, they will probably know.

If they can't supply a part, you could put the measurements into this website to see if a compatible seal is available:

https://simplybearings.co.uk/shop/Produ ... index.html

I've no connection other than to be a long term customer of theirs.