The BSA A7-A10 Forum
Technical (Descriptive Topic Titles - Stay on Topic) => A7 & A10 Engine => Topic started by: iansoady on 08.08. 2012 16:44
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Me again. Now in the process of refitting the dynamo.
When I fit the inner timing cover I find a lot of end float on the timing idler gear - I haven't measured it but it is certainly more than the few thou mentioned on other threads here. I can't find an mention of shims etc in the BSA service sheets or the haynes book - in any case, both sides of the gear rotate against their respective bushes so a shim probably wouldn't last long in there. I've selected a cork washer for the breather that gives a few thou pre-load and everything seems to turn quite nicely.
Have I lost a spacing washer or something while the timing side has been in bits? Or am I worrying unnecessarily?
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G'day Ian,
once you fit the dynamo drive sprocket with sealing cork/felt behind you should have very little end float.
Cheers
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nothing but the tightness of the fit keeps the idler gear in any respective place along it's shaft, so as musky states it will most likely be sorted once the dynamo sprocket is on, if not then supporting (not gripping) the idler gear on a vice the shaft can be tapped through a bit either way, (careful what you tap it with of course)
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Hi,
Are we talking the gear/shaft that meshes with the crankshaft pinion, and also has the larger of the 2 dynamo spockets on it?
If so, I guess two of methods to reduce end float would be to:
a. Fit a shim underneath the the "brim" of the bush (if you look at the bushes as being top hat shaped)
b. Or much better, replace a bush with one with a thicker 'brim"
As to what the max end float is before it becomes a problem I don't know, maybe if it noisy something needs to be done?
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I did a post a while ago; re this- when I was having issues fitting the genny belt pulley(s). Almost 0.020" !
I considered moving the gear on the shaft as b-Bil says, but if I were to go one way, the back of pulley would rub, if I went the other way, the pulleys/belt-sprocket/chain would be out of alignment, so I decided that as there's no apparent need for end-thrust on the gear, a bit of end float won't matter, as the belt/chain will self-align everything, and as there's constant change of 'rotational thrust' on the gears, it's a constant self alignment- in theory, and so long as the gear is located appropriately!!
And it also depends on the thickness of the inner gasket.
I may be wrong.
Cheers,duTch
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Many thanks all.
I don't have the seal (will pop down to C&D later to get one) so maybe that will sort it out. But as the consensus seems that I don't have a problem, onward and upward......
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Seal bought & fitted, end float gone, dynamo charging, sun shining.....
Many thanks all.