JSM JS2 cam and 2 degrees of cam advance

The JSM JS2 cam and 2 degrees of cam timing advance greater than straight up dot to dot works really well on "my" P11 750. I used the JSM 2-degree stepped cam key to add to the cam timing. I did not measure anything to see where the cam was at cam timing wise straight up. Numbers might make me appear as if I know what I'm doing, and I can't have that. Every motor may be different anyway, and frankly I don't care that much. I figure Jim did all the homework to get things right with his cams dot to dot timed.

Really a pleasure to ride, and I don't know why anyone else would think otherwise. Ignition timing needs to be at least on the money using the static timing method for the ignition being used. I'm using the TriSpark ignition, a big Harley dual coil, and Denso Iridium plugs. Sparky

This is what my plugs looked like after doing 8 or 9 miles at 65 and 70 mph on the Hwy and 12 miles of 30 mph and stop and go in city riding. Blipping the throttle in the garage turns them basically black as witnessed by the outer ring. Riding is better than blipping.

35mm FCRs feeding the engine through my modified Commando manifolds. For the guys are sure they know stuff they are not straight manifolds and they are definitely one offs. Jetting is as the 35mm FCRs came from Sudco, which is race jetting. I turned some adjustment screws and have the needle set at the 4th clip down from the top plus a half step shim. So 4.5 down from top clip position. As I may or may not have mentioned I don't know how many times, the head was taken to the UK by Phil Radford in a suitcase while Phil was on vacation (he could have ben kidding about that) and ported by Fred Barlow. He was not kidding about that part. I think the head works exceptionally well as long as the exhaust and timing is right and crank case pressure is eliminated when it needs to be. I'm using a cNw reed valve on the back of the timing side case and the cam timed breather right out to atmosphere through a Ford PCV valve.

I also get mid 60's fuel milage with the 35mm FCRs.

Repeating myself more than likely.

As most of the talk on the web indicates the improvement with the right amount of cam timing advance is in the low end and middle of the power band where these old Nortons get ridden the most on the street. The top end which I barely touched the start of in 3rd gear getting on the Hwy still has plenty of pull, but the exhaust note sounds a little different. Like the AFR is improved. I didn't push the engine though due to traffic. Plus, I think a cop might have been following me. He caught up on the Hwy exit and followed me for a mile or so. I firmly believe he was hoping I never look in my rear view and was going to turn the wick up. I rode at the speed limit and he got in the next lane over and went around me eventually. Whatever the case many things came together, and, in my case, the 2 degrees of cam timing advance are an improvement with the JS2 cam. It would probably work well with a 2S cam and stock cam, but I have no plans to find out.

The stepped key is just a little bit of work to install, a few seals, maybe a new cover gasket, and resetting the ignition timing if your ignition trigger is in the timing cover. I use the JSM timing cover gasket which is reusable.