Hi, according to my (dutch) manual), which came with the BSA over 50 years ago, the lenght of the valve springs is 2".
The same as the valve springs in the engine.
Now I see that the new ones are 2 1/4".
Why the difference.🤔
John
Hi Michael, I see. They all over the internet for sale and also mention the lenght. On eBay, Feked, British Only Austria and so on.
Mine are from BSA de Groot.
The old valve springs are less then 2".
John 😟
From what I know and checked once years ago, the springs offered in Europe are partly imported from Indian products and some of a poor standard, while some are made in Europe itself and I have not heard any complaints about them, but then again, that was many years ago.
I think I finally got mine from Draganfly as they declared it as a UK product.
Lots of 'tapping' can come from excessive play on the camgearing, I figure that when the cam goes over it's highest point the valve spring 'drives' the cam for a moment and pushes the play out which give the tap, then the crankshaft takes over the drive again and this gives another tap....
If you have play on the gears I image that new/stronger valve springs may even increase your tapping...
Luckally the BSA timing set-up is a great design with it's fixed camspindles, so play can easily be detected.
I'm sure they will work just fine John. Yet the standards book quotes the maximum length to be only 2 1/64". I wonder why someone decided they should be longer. Drags even quote a different part number for M20 valve springs?? Ron