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Allan G, Gary Caines, Gordon Gray
Total Likes: 6
Original Post (Thread Starter)
#896123 11/22/2022 3:42 PM
by Spino
Hi folks. I’m reassembling a late-60s BSA Victor 441 motor. The manual says to align the timing marks on the oil pump gear and the cam gear. Simple enough. However, my cam gear has two timing marks. One is a line, and the other is an arrow. I’m inclined to line up the line mark, since it matches the mark on the oil gear. Any objections? Can you explain why there is an arrow mark on this cam? Thanks in advance!

Liked Replies
#896267 Nov 24th a 02:13 PM
by Gordon Gray
Gordon Gray
Originally Posted by Allan G
Originally Posted by DAMadd
Experts may weigh in, but the Rupert Ratio book says in bold:
"If the V is present it must be used in preference to the dash"
So that's what I did.

[Linked Image from]

Does it say why the V is used in preference? it doesn't show as a "Must" on the image, just "V timing marks used in prefrence to other timing marks".. Just thinking that there must be a good reason why there are 2x timing marks and not just one?

Allan, Rupert's goes on to explain the pretty good detail. Basically claiming that the "V" is the newer of the marks and should be used if present. States that the 'V"'s location can vary? Then gives you a way to check them. Very helpful.

I just checked my paper copy of the Workshop Manual and my copy doesn't mention the "V" either. My guess is there's a Service Bulletin out there somewhere?

Just another reason to get a Rupert's.........worth every dime you pay for it.
1 member likes this
#896294 Nov 24th a 07:00 PM
by kommando
Wheels can be moved easily from cam to cam over the years so I always check the timing before putting the timing inner cover on.
1 member likes this
#896323 Nov 25th a 12:23 AM
by Gordon Gray
Gordon Gray
I'm going on memory here which can't be trusted but I think Ruperts mentions that the "V" can be off by a couple of teeth in either direction??? So if you change gears/cam you need to check.

Can't say I've ever run across least so far.
1 member likes this
#896388 Nov 25th a 10:54 PM
by Opo
Here is the explanation, from B25/50 Workshop Manual 1971:
1 member likes this
#896439 Nov 26th a 04:15 PM
by Mr Mike
Mr Mike
My thought on the two marks is this: At some point in the development of the unit single (for whatever reason) they found that the original timing mark was not optimal. Rather than make a new gear with a new mark, they simply added a new mark (the "V") so that the gear could be used interchangeably with different models of the unit single. I have no idea whether this is correct, but it seems plausible. Industrial Engineers, back in the 50ties and 60ties were focused on simplicity in manufacturing and supply chains to improve efficiency and reduce cost. Changes to the supply chain or manufacturing process were minimized. This in part likely led to the demise of BSA. They were promoting bikes that were designed in the forties, and the Japanese embraced a wholly different philosophy and had newer designs and much improved motorcycles to offer.
Guys like me grew up in an age when long stroke pushrod engines were the norm, and we were comfortable working on them. I rarely work on today's engines and fortunately I don't have to very often. They really are better.

Mr Mike
1 member likes this
#896452 Nov 26th a 05:34 PM
by kommando
The difference is a a few teeth, too much for a slight correction of an existing cam, there must have been a change in the cam at the same time as the new mark. Never looked into it but have swapped so many wheels over its just second nature to check the timing and ignore the marks.
1 member likes this
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