John, to compare the RTV 1200 Vincent to Terry's current 1360 ccracebike, which produced 165.2 rwhp on dyno, is a bit like comparing a Commando to a 2015 gixxer 1000. Though Terry had some good ideas with the RTV, it was very early days
in his experimentation. Everything that matters has been changed then changed again several times. Think modern day Burt Munro. Burt started with a bike that had perhaps 15 HP and went 60 MPH then modified it again and again until it broke 200 MPH. Terry is doing a similar thing, but started with a bit better candidate, the Vincent engine which is no slouch in stock form.
Terry bought the bike as a stock Rapide about sixty years ago when he was 17 years old and still living in England. It has had many forms over the years.
Dave, I suppose by your measure maybe the cost isn't quite so outrageous, so thanks , I will use your point as my rationalization going forward :mrgreen:
Re valve size. My engine uses standard Vincent sized valves, which are quite large, 2" for intake and 17/8" for exhaust if memory serves. Phil Irving liked to use a large valve and low lift, which made hotrodding this component easy , just add a bit of lift. Standard lift for a road going twin is just. .312" which jumps to. 343" for Irvings hotrod "Black Lightning " cams. Terry Prince went much higher , all the way to .460" with his MK4 race cam. Fritz Egli Jr. used the Mercedes Formula One Race Team's cam development program to design Terry's MK5 cams. The program said that with 6500 rpm as the intended Max output rpm, there was no point in lifting the valves more than .440 intake and. 425" exhaust, so that is what the MK5s do. Both Terry and I have these MK5s installed and they work extremely well. A nice lumpity lump no stall idle, then good controllable power just off idle, then anywhere above 2000 rpm, hang on!
I'm not sure what size valves Terry is using.
Glen