Author Topic: A7 Dynamo sprocket removal  (Read 917 times)

Offline Bsa Nut

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A7 Dynamo sprocket removal
« on: 31.10. 2013 22:27 »
Hey everyone,

Separating my latest project, a '53 Star Twin.
(Not new to BSA, just new to A7 motor.)

Question: I have a stuck and rusty dynamo sprocket that has been laying open with the nut removed.
It's rusty to the point that not much thread is visible beyond the sprocket. I douched it down with penetrating oil,
along with the stuck pistons, I'm going to let everything soak for a few days before attempting anything.
What is the best way to remove this sprocket??? Three jaw puller with some heat??
Someone obviously started removing parts off this motor to get it split, but ran into problems and stopped.

Please advise with some past experience...trying to tear up as little as possible while she comes apart.


Offline a10gf

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Re: A7 Dynamo sprocket removal
« Reply #1 on: 31.10. 2013 23:14 »
A dose of some\all of the ingredients: heat, oil, tapping, puller,  ...and patience  ;)


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Offline Bsa Nut

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Re: A7 Dynamo sprocket removal
« Reply #2 on: 01.11. 2013 00:13 »
Thanks a10gf...

That's about what I anticipated. Figured it was a tapered shaft, but wasn't for sure.
I'll keep spraying and heating over the next few days. Then apply the rest of the ingredients.

Offline muskrat

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Re: A7 Dynamo sprocket removal
« Reply #3 on: 01.11. 2013 10:15 »
G'day Luke. If all of the above fails.
The dynamo can be removed with the sprocket on. Once removed it's easy to use a small bearing separator type puller to remove the sprocket. The drive sprocket will come out with the inner timing cover, it will bring the idler pinion with it. Once removed place the cover on blocks of timber either side of the pinion and give the shaft a bit of gentle persuasion with a hammer and copper drift.  *bash*
Warning do not try to turn the motor over with the idler pinion removed. Valve damage may result.
'51 A7 plunger, '57 A7SS now A10CR,  '83 CB1100F, 88 FXST .
Muskys Plunger A7