Author Topic: Lessons From A Standard OEM Timing Side Bush?  (Read 308 times)

Offline Peter Gee

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Lessons From A Standard OEM Timing Side Bush?
« on: 24.05. 2018 20:50 »
Dunno how well this will turn out when I re-sleeve my TS OEM steel bush with SAE660 - as I don't intend to do very many miles., but it says alot about topics raised on here..namely the wearing effect of various bronzes on the timing side crank bush and the merits of different materials.

My 59A77SS  bought stored since the late 1960's has never been opened. It has about 38K miles on the Smith's. When opened , it had the original steel lined TS bush with a pegged lead bronze (LB2?) liner/insert.

Took the crank down to be professionally measured up. The obality of the TS journal was half  a thou. The ovality of the bush insert was 0.004". So BSA were wise indeed to use such a forgiving materiel as lead bronze.

Of interest I have no intention of grinding to 0010" under. I shall have a new insert in SAE660 pegged and pressed-in, then line-reamed/bored to .00005 to .0001". I would have preferred LB2 or LB3 but they seem impossible to get in small amounts.

Offline chaterlea25

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Re: Lessons From A Standard OEM Timing Side Bush?
« Reply #1 on: 24.05. 2018 23:11 »
Hi Peter,
then line-reamed/bored to .00005 to .0001"

That's almost a press fit *eek*
I believe 0.0015 is the correct figure

1961 Super Rocket
1963 RGS (ongoing)

Offline muskrat

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Re: Lessons From A Standard OEM Timing Side Bush?
« Reply #2 on: 25.05. 2018 10:41 »
G'day again Peter.
Have you measured the case bore. It has been known to elongate. If it has you should get it bored and make a solid bush to suit.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Muskys Plunger A7