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Gearbox grief

Posted: Sat Sep 11, 2010 3:34 pm
by Daggs
Today i've been assembling a gearbox and attempted to shim it up..chuffin' miles out.
I've fitted a Spanish layshaft into a Spanish casing and an Indian hub bearing . I'm building from scratch and the endplate i have, i don't know the origin of.
The gap to be shimmed is 4.4mm leaving about .5 mm float. Obviously i can't put 4.4 mm of shims in there.
I happened to have another blokes engine here and borrowed his Italian endplate. This gives 4.3mm of shimming leaving about .5mm float. So something ain't right.
I've compared the Spanish layshaft with an Italian one and there is no significant difference in the measurements all round.
So now my suspicion falls on the Indian bearing which 'fitted' a treat. Or did it?
Does anyone know if the hub bearing usually protrudes into the casing, if so by how much? The one i've fitted sits dead flush.
Help and thoughts and opinions please.

Re: Gearbox grief

Posted: Sat Sep 11, 2010 3:55 pm
by bristolmod
Andy

TBH I don't know if they protrude into the crankcase area.

I've given up using remade rear hub bearings as they all appear to be a waste of space- I now use a good "used" Innocenti item whenever a hub bearing needs replacing (which ain't ofter!)- often you are throwing out a perfectly usable item in favour of remade rubbish.

If you need a good used Innocenti item give me a shout- there's probably one out there somewhere

Chris

Re: Gearbox grief

Posted: Sat Sep 11, 2010 4:15 pm
by rocho68
i wouldnt touch an indian hub bearing , dont go to all the trouble then have to change it !!! also you are getting the gauge under the lip on the endplate ?

Re: Gearbox grief

Posted: Sat Sep 11, 2010 4:27 pm
by Daggs
rocho68 wrote: also you are getting the gauge under the lip on the endplate ?

Yes, i've had the endplate in and out dozens of times looking and checking.

Re: Gearbox grief

Posted: Sat Sep 11, 2010 6:13 pm
by wack 63
Just done a gearbox rebuild with original Italian bearing and it protrudes into the casing by a few mm, so either your bearing isn't fully home or its too shallow which will allow the swivel and selector to hit the casing I would have thought. Time for a strip :(

Re: Gearbox grief

Posted: Sat Sep 11, 2010 6:38 pm
by bristolmod
Daggs stripping...................the mind boggles :shock:

Re: Gearbox grief

Posted: Sat Sep 11, 2010 11:35 pm
by byron
rear bearings are usually fairly flush inside the casing...
that's a massive gap....
what cogs are you using ?

Re: Gearbox grief

Posted: Sun Sep 12, 2010 8:34 am
by coaster
MB do a high quality rear hub bearing, had one in my LiS for some time now with no issues.

Re: Gearbox grief

Posted: Sun Sep 12, 2010 6:54 pm
by Rich_T
Hate to ask the obvious, but the only way I can see that you could get such a large gap would be if you have fitted the 4th gear the wrong way round. Are you sure you're not having a crack head moment?

I'm making gearboxes at the moment so the numbers and measurements are very familiar to me at the moment. there are some small differences in Italian/Indian rear axels and sliding dogs but overall the end plates and casing differences are really minimal (0.5mm or so). 0.5mm is a significant difference for what I'm up to but this should be nothing for a run of the mill installation which is what you're doing.

I've just played around with a gearbox right now and the only way to get this difference is to fit 4th gear the wrong way round unless you have some strangely miss matched gearbox components like two 3rd gears being used, one in place of 2nd. My money is on you having 4th the wrong way round.

Re: Gearbox grief

Posted: Mon Sep 13, 2010 12:50 pm
by paul213
what gearbox ? I had a gp200 indian box where 4th gear hadn't been machined correct recessed both sides no way of shimming the box took me ages to find it as was given to me to fit as new complete box. new 4th gear and it shimmed up correct