Venturing into deep water here lol. I'm in the process of replacing my Magneto. Took the timing cover off and as in photo's the nut on the Mag has been chewed , not a problem I had a new one .Mole grips on the offending nut and it came straight off with the gear without applying hardly any pressure .The problem was I couldn't get the nut out from the gear :thinking_face: , had someone burred the edge over and it wouldn't clear the threads for the puller , so got the puller out and it parted company ,:face_with_rolling_eyes: Duh ,the nut had a flange on and was held in place by the riveted washer :grimacing:

Does anyone know what this gear is off , the bolt is flanged and fixed behind the washer which is riveted in place , so not the one according to the spares manual .

Be interesting to know what its original fitment was .

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That looks like a Triumph 3HW magneto pinnion.

Yes, the Triumph gear has a 'self extractor' set up whereas the M20 gear is a plain gear with a shoulder on the back to engage the oil seal and a recessed thread in the front for a puller to get it off the shaft...
If you're buying a used gear at any time check that the extractor thread is good and that the shoulder on the rear is not worn/corroded where the oil seal should run...
Extractors can be bought from various BSA dealers I believe...Ian

email (option): ian@wright52.plus.com

Thanks for clearing that up for me .A Triumph pinion will obviously fit if a BSA pinion isn't available? . I've ordered another from Draganfly including a nut washer and seal, also the 2 seals that fit in the timing cover as they have seen better days .

Just to confirm what the others have said Dave, here's a picture of my 5SW. Ron

email (option): ronpier@talk21.com

Thanks Ron, and there's me thinking the nut was stuck in the gear :grin: .Seems a more practical idea, a self extracting pinion rather than having to use a puller .

Dave

Triumph did have the best idea to my mind. A removable cap in the timing cover to save taking the whole cover off and an integral nut/puller that can be operated with a simple 1/4 W socket.

BSA is next best if you have an early timing cover with the inspection plug. Royal Enfield are a bit of a work up as apart from the 9 nuts to remove and the oil spill from the cover, you usually also have to remove the exhaust system. Matchless and Norton have very easy access but I just hate the idea of levering sprockets off and getting the chain adjustment satisfactory.:angry: Ron

email (option): ronpier@talk21.com

I've seen the timing covers for the BSA with the inspection plug and wondered if it would be worth getting hold of one , but then would it detract from its originality (1941) the engine and frame are matching .I do like to have things as near original as possible .

NB.
I managed to get an Altette horn to replace the hooter you spotted from my photo a while back :+1:

Dave

My own M20 is a 1940 frame with a 42/43 engine and has evolved over the 30 odd years that I've owned it into a bike that might have been upgraded and retro fitted through the war years (panniers/pillion/Vokes etc) So a mixture of early and later parts. I have several bikes that I've paid attention to the ex factory specifications. But my M20 is my good old faithful usable bike. Ron

email (option): ronpier@talk21.com

Personally I'm not a fan of the covers with an aperture for setting timing...The holes aren't big enough to get the gear through and it isn't possible to take a look at the gear mesh, oil seal condition or anything else...In fact I find the whole exercise over fiddly..I don't mind removing the cover to get better access to everything with full size spanners etc...Of course that doesn't apply to the Triumph where, as usual, they have made timing cover removal over complicated due to the oil pump location....Ian

email (option): ian@wright52.plus.com

Ah yes good point Ron .When I bought the bike I was told it wasn't as it left the factory but the additions to it were correct for its progress throughout the war , panniers , pillion etc , so it wouldn't be incorrect as such to fit a different timing cover?

I've also taken on board what Ian say's about access etc , if I hadn't taken the cover off I wouldn't have found the worn seals , so maybe wise to stick with the original cover .

Dave