W33-7 Camshaft

[Beeza32]

At long last I've run my W33-7 but there is excessive noise from the inlet camshaft 27-1470. It would appear I'm in need of an oversize pinion so the gears mesh closer to stop the cam "flicking" over at the highest point of the lobe. Can anyone suggest where I might get an "x" marked cam or a fix for my problem. Thanks  Rob

[David Samways]

Hi Rob

Are you saying that there's excessive backlash between the crank pinion and the inlet camshaft pinion? Have you replaced the inlet cam? Have you got the springs fitted to the pushrods?

David

[Beeza32]

Hi David thanks for your interest. Yes there is far too much backlash, as for the history of the cam I could not say. The Ex cam is an oversize one and when I substitute the In cam with it the backlash is taken up, therefore I'm thinking an oversize In cam will do the trick. To say the cam is oversize is not exactly accurate as it is the pinion its self that's oversize thus reducing the backlash. I think the springs are fitted, it's been a long time since I put the engine together!

[David Samways]

A curious one Rob. I wasn't aware that BSA made oversize pinions since they're not listed in any part book I've come across.

[Beeza32]

Hi David, I got this info from a book on BSA maintenance  by D.W.Munro and I'm sure I've read about elsewhere but can't recall where or when.

[David Samways]

Hi Rob. What page of Munro, couldn't find any reference in it myself, but my curiosity continues!

Where abouts are you? I've got a 34 machine and would be willing to remove the cam if you're not far from Ipswich.

David

[Beeza32]

Hi David, the info is on p69, "noise due to camshaft pinions". The book is BSA Motor Cycles, a practical guide covering all models from 1931. The plot thickens a little as I've come across an inlet cam 27-1470 with a small letter "E" right above the piled arms stamping. I hope to try this in my bike today so please don't bother checking yours yet, I'll let you know. While I'm talking to you what oil do you put in your gearbox?
Cheers    Rob

[David Samways]

Interesting. Not got to filling the gearbox yet. Many here have recommended thixothropic grease which I think I'll adopt given poor sealing.

Do post on how you get on. I've not run either of my machines yet so it's possible I'll have the same issue.

David

[Bicycle repair man]

The cam 27-1470 comes from a a W35-7, the standard 4.99hp ohv model as opposed to the Blue Star.
I always thought that the letter above the Piled Arms logo is the production year. In this case, 1935. You see this on a number of parts, not just gears.

[Bicycle repair man]

Just checked, it's also used on the SV model.