Author Topic: Re-Bushing outer gear box cover  (Read 1576 times)

Offline LJ.

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Re-Bushing outer gear box cover
« on: 05.07. 2008 11:08 »
I wonder if these come deliberately over sized and have to be machined for the kickstart and gear selector spindles to fit. I did not have to remove much and soon got a nice snugg fit with the use of some grinding paste. The result is a nice oil tight bush and better effort on the gear selector which I also renewed. Always something to do on these old bikes eh.  *smiley4*
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline bsa-bill

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Re: Re-Bushing outer gear box cover
« Reply #1 on: 05.07. 2008 17:43 »
I have got to the same point in the project - have fitted the two bushes and now need to get the shafts to fit, I will try your method

All the best - Bill
All the best - Bill
1961 Flash - stock, reliable, steady, fantastic for shopping
1959 Rocket Gold Flash - blinged and tarted up  would have seizure if taken to  Tesco

Offline dpaddock

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Re: Re-Bushing outer gear box cover
« Reply #2 on: 06.07. 2008 14:55 »
One should never use valve-grinding paste on bronze or brass bushings; the bush will retain some of the emery (which is why brass laps are used) and wear the steel shaft journal over time.
Either ream the bush (best practice) or reduce the journal diameter.
David
'57 Spitfire


Online trevinoz

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Re: Re-Bushing outer gear box cover
« Reply #3 on: 06.07. 2008 23:13 »
The gearbox cover bushes are steel.

Offline dpaddock

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Re: Re-Bushing outer gear box cover
« Reply #4 on: 07.07. 2008 14:57 »
If steel, OK.
David
'57 Spitfire


Offline LJ.

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Re: Re-Bushing outer gear box cover
« Reply #5 on: 08.07. 2008 10:24 »
Phew! Yes they're steel.  *lol*
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Online groily

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Re: Re-Bushing outer gear box cover
« Reply #6 on: 09.07. 2008 09:53 »
Good UK source of inexpensive adjustable reamers is RDG tools at rdgtools.co.uk (I think). They sell sets of small and medium ones, which get you up to an inch dia. Also lots on e-bay I think. Have used mine several times for exactly this purpose - gearlever outer cover bush ( made in bronze), and also for doing small ends. I never feel great with reamer in hand because it really is a case of slowly does it, a fraction at a time. They jam if you're too ambitious, which can make a bigger mess than you started with. Don't ask me how I know!  Subject to that proviso re the learning curve, and subject to never reversing the direction of rotation, even when withdrawing, the results have been perfectly OK.
Re the Q of whether they're made oversize, sort of yes. The inner dia shrinks when inserted - or they do if they're a decent fit in their housing. In theory it's presumably possible to make them exactly so that with the shrinkage they'll be perfect when installed . . . but life's not always that simple . . . wear on shafts, wear in housings etc. Hence, fitting is normally needed.
Bill