BSA Owners' Club Workshop Discussions

The BSA Workshop => Twins => Topic started by: spike123 on 12 Sep, 2022, 03:57

Title: Crank washer
Post by: spike123 on 12 Sep, 2022, 03:57
Hi guys
On my a65 do you which way around the shamfer goes on my crankshaft the washer between the crank timing gear and oil pump drive
Cheers
Title: Re: Crank washer
Post by: Spaceman on 12 Sep, 2022, 06:41
Neither Haynes nor the workshop manual mention which way round it goes. My guess would be that the chamfer goes on the worm drive pinion side and that it is only the non-chamfered outer part of the washer that contacts the pinion? To some extent, it should be obvious looking at the two pinions either side of the washer why the chamfer is there?
Title: Re: Crank washer
Post by: spike123 on 12 Sep, 2022, 07:48
Yep that's the point it's not obvious
Title: Re: Crank washer
Post by: Spaceman on 12 Sep, 2022, 08:04
It is chamfered for a reason. This is either because it is done to provide clearance for the Woodruff key or slot on the timing pinion side or because of the contact nature of the worm drive pinion thread on the other side. As said, I would have thought it would be possible to see which of the two possible reasons for the chamfer apply by carefully looking at the components?
Title: Re: Crank washer
Post by: DAVE BRADY on 12 Sep, 2022, 09:56
Hi,

I think that the chamfer goes inwards to clear the small radius that exists at the step down in the crank for the pump worm drive as well as any slight protrusion of the end of the woodruff key.

Dave.
Title: Re: Crank washer
Post by: spike123 on 12 Sep, 2022, 12:38
Ok thanks fellas will have another look tomorrow
Title: Re: Crank washer
Post by: Mike Farmer on 12 Sep, 2022, 16:50
 :) :) :) :)

You could give SRM a ring and ask. Please let us know the result.

Mike 8) 8) 8) 8)
Title: Re: Crank washer
Post by: Spaceman on 13 Sep, 2022, 09:40
I have looked at a number of pics of the installed washer (without worm pinion) and, although not definite, it looks as though Dave Brady is probably correct - the chamfer is on the timing pinion side for the reason given.
Title: Re: Crank washer
Post by: spike123 on 16 Sep, 2022, 03:04
Yes I think your correct