Mod 8 gearbox Main bearing

Ozmadman · Post by **Ozmadman** » Sat Dec 24, 2011 1:22 am

H'mm. interesting stuff and good to have another "slant" on the whole thing. A spanner in the works that's worth delving into a bit further I think

Cheers PaulEdited by - Ozmadman on 24 Dec 2011 01:24:03 AM

bigwol · Post by **bigwol** » Sat Dec 24, 2011 10:56 am

Can we tempt you into joining the club Paul? I'm a fairly new member and from not too far from you in Essex, there is a section at North Weald airfield I attend and another in the Colchester region. Personally I'd be glad to have a few more members around who are still working and not retired as a lot of the ride outs are mid week so unavailable to me. Would be great to have some interest in the odd Sunday outing. By all means contact me if you want a chat.
Dave

Ozmadman · Post by **Ozmadman** » Tue Dec 27, 2011 2:53 pm

And finally, hopefully, on the gearbox front.... from all you guys and experience of leaky British bikes.. What gasket cement would you recommend for sticking my box back together with which gives it the least chance of leaking???

Paul

Duncan · Post by **Duncan** » Tue Dec 27, 2011 11:33 pm

For a gearbox, flat square surfaces, correct gasket and a smear of grease. You will curse any jointing compound when you need to open it up again to replace that bearing.

paul knapp · Post by **paul knapp** » Wed Dec 28, 2011 5:02 am

.............So there you have it,
you have to decide between a 'weepy' box that is easy to open when needed,...OR... an oil-tight box using modern sealers, that will need a bit of a nudge to open, should the occasion arrise.

Ozmadman · Post by **Ozmadman** » Fri Dec 30, 2011 3:20 am

Just started rebuilding my gearbox and one of the bushes I replaced was the lay shaft bush in the case (the one next to the main output shaft bearing). Just to check it was ok I put the top gear on the lay shaft and then pushed it into the newly fitted bush only to find that the gear rubs on the casing. I tapped the lay shaft bush fully home when I fitted it (the flange of the bush is lower than the casing) There is no shim/washer listed in the parts book to space the gear away from the casing. Realising that the bush has a thrust face on it and the top gear MUST be able to run against it I decided to remove it only to find that the flange on the new bush is about half the thickness of the old bush??? hence the reason why it sat below the casing level. Is there a mod here(maybe a spacer washer under the bush flange?) or is the bush wrong to spec does anyone know, got it from Jampot spares part number 041289. Actually the old bush fits the shaft fine but is a loose fit in the casing as it just drops out. There is a picture of the differences in the photo's section

Thanks PaulEdited by - Ozmadman on 31 Dec 2011 11:26:13 AM

Ozmadman · Post by **Ozmadman** » Thu Jan 05, 2012 8:53 am

quote:
Just started rebuilding my gearbox and one of the bushes I replaced was the lay shaft bush in the case (the one next to the main output shaft bearing). Just to check it was ok I put the top gear on the lay shaft and then pushed it into the newly fitted bush only to find that the gear rubs on the casing. I tapped the lay shaft bush fully home when I fitted it (the flange of the bush is lower than the casing) There is no shim/washer listed in the parts book to space the gear away from the casing. Realising that the bush has a thrust face on it and the top gear MUST be able to run against it I decided to remove it only to find that the flange on the new bush is about half the thickness of the old bush??? hence the reason why it sat below the casing level. Is there a mod here(maybe a spacer washer under the bush flange?) or is the bush wrong to spec does anyone know, got it from Jampot spares part number 041289. Actually the old bush fits the shaft fine but is a loose fit in the casing as it just drops out. There is a picture of the differences in the photo's section

Thanks Paul

HAS NO-ONE COME ACROSS THIS BEFORE???Jampot are selling the bushes under the original part number but this will cause serious damage to the gearbox casing should it be fitted. From what I see here the boxes are always causing problems, this bush seems to come out with the lay shaft most times a box is dismantled and I would really like a new bush for my rebuild instead of "sticking" the other one back if possible. But no reply from Jampot after two mails either?? is it any wonder people wander away from here to source their spares? There is a picture of the differences in the photo's section which I have mailed to Jampot as well..Edited by - Ozmadman on 05 Jan 2012 10:21:43 AM