Author Topic: Confused - Crankshaft end float. Help!  (Read 976 times)

Offline bsaketcase650

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Confused - Crankshaft end float. Help!
« on: 19.03. 2011 17:08 »
 ????
Hi,

I am rebuilding a 1953 A7 Star Twin,  engine number starting BA7 S.... I am trying to pin down precisely what the end float measurements should be for this model. I know that this topic has been well covered elsewhere so apologies if I seem to be going over old ground, but I want to make sure that I get this right.
The BSA service sheet (No 208  - dated 1948 reprinted June 1960) states "On the A7 when the sprocket is tightened up, the float is taken up. Before tightening the end float should be .005" - .010".
The same service sheet states that for the A10 end float should be no more than .005". I also note that it states that A10 instructions apply to all machines after engine number AA7-101
Would anyone out there be so kind as to tell me what the correct measurement is for my particular machine.

Thanks

Simon

Offline Goldy

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Re: Confused - Crankshaft end float. Help!
« Reply #1 on: 19.03. 2011 17:31 »
The usual end float is .003" as per service sheet No 215. I rebuilt my engine recently and ended up with 004" and I left it at that. You will find that Haynes manual specifies .005" My personal opinion is that a few thou will not make much difference and if you end up with 3 to 5    I would suggest that,s ok.
56 A10 Golden Flash - Restore, ride, relive.                                          
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Online bsa-bill

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Re: Confused - Crankshaft end float. Help!
« Reply #2 on: 19.03. 2011 18:06 »
I agree with Goldy   .003 max
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

Online Brian

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Re: Confused - Crankshaft end float. Help!
« Reply #3 on: 19.03. 2011 20:46 »
The early engines had a ball bearing main and the later ones a roller. With a ball bearing main when you do up the cush nut there is no end float, it all locks up solid. The A7's continued with a ball for some time after the A10's had gone to a roller. With the roller you always have end float and it must be shimmed to remove it, I put my engines together with as little as possible so a max of .003" is correct.

Offline bsaketcase650

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Re: Confused - Crankshaft end float. Help!
« Reply #4 on: 20.03. 2011 19:23 »
Thanks chaps. One again the forum comes to the rescue. Much appreciated *smile*

Regards to all,

Simon