I'm interested in these S cams. I have a 2008 AVL and have had up to 75, but was afraid to push it any farther. Are there any other modifications to the engine, carb, or electrical to use S cams? I have the stock CV carb. My bike is pretty much stock mechanically, except that I have removed the stock air box and oil bath air cleaner. Although more power would be nice, I am concerned about ruining the great gas mileage this bike gets. I'm setting this bike up for long distance traveling.
Hi Buckeroo,
The 'S' cams will make an improvement on their own, but really come into their own with other modifications, too. Personally, I would raise the compression ratio to 9.2:1 [I shorten the cylinder barrel and modify the piston crown to achieve this], Straight through 'Goldie' silencer - ie the type with the perforated tube and wadding inside that you can look in one end and see out the other and NOT the staggered metal baffle type , the performance CDI [TCI] - I pioneered these and they make a difference on their own and a nice, big, Amal MK II - I tried 32mm [MK I], 34mm MK II and 36mm MK II and the biggest gave the most power throughout the rev range - no flat spots, good starting and idling. I also fitted a 19t gearbox sprocket in place of the standard 18t job, to raise the gearing a little, although this machine had an 18" rear wheel. In my quest to prevent the violent valve bounce, which acts like a rev limiter, I had also fitted a set of double competition valve springs as available for the 'Classic' engines, but these may not be necessary, as I still had valve bounce after fitting them - it was the fitment of the 'S' cams that sorted it.
I am currently weighing up getting more 'S' cams made, unfortunately they are not cheap, due to the small numbers involved when I order them, but they definitely work !!
B.W.[