The stock springs are fine. These cams are supposed to be a simple bolt on replacement, no springs or valve work required. Maybe just a shim here or there to readjust the clearances, but that's supposed to be all there is to it. I was told that they are the farthest you can take a cam on these bikes without reworking something. And they are made special for a 904 Speedmaster. How convenient! We'll see.
Oh, and let me add this too, I have been talking with some of the other racing bonneville guys and have been told that we can simply put another intake cam in the exhaust cam spot and gain a good deal of HP. Seems simple enough, and the price of a stock cam is a lot less than custom grinding cams.
Don't say I never told ya any of my secrets now.
