Forgive me if you`ve heard this before, but I`ve only been a member for 1 month.
I recently stripped the head on our 426 and mentioned to a nephew what I was doing (He`s a race team manager and ex 24 hr endurance racer) He advised I refit the camshafts without the valves to see what happened! I was intrigued, but did what he said. Intrigue turned to pure disbelief. The camshafts would hardly move,3times I removed them and refitted them doing everything by the book still they hardly moved.When I spoke to him again he infomed me this had always been a common fault with the bikes they raced and releasing the shafts was good for about 4/5 BHP.Needless to say I followed his advice and lapped in the camshafts.
The procedure is to use fine grinding paste on the plain journals apply finger pressure to the caps initially and start to turn the cam wheels in a back and forth motion moving the wheels about 1/4 turn every few moments. Gradually the bolts can be torqued down whilst still lapping to about 4ftlbs. Don`t continue until the shafts spin free, stop when they will spin about 1 turn with 1 finger,because they free off slightly when the head is torqued down.Finally don`t forget to wash off every trace of grinding paste or it will destroy the engine in a few seconds. We tried our 426 this weekend after carrying out the above and the difference is amazing, the bike just wants to keep revving and is much crisper off the throttle.
I would like to know if anyone else has had this experience.
Regards, Kevin.
I recently stripped the head on our 426 and mentioned to a nephew what I was doing (He`s a race team manager and ex 24 hr endurance racer) He advised I refit the camshafts without the valves to see what happened! I was intrigued, but did what he said. Intrigue turned to pure disbelief. The camshafts would hardly move,3times I removed them and refitted them doing everything by the book still they hardly moved.When I spoke to him again he infomed me this had always been a common fault with the bikes they raced and releasing the shafts was good for about 4/5 BHP.Needless to say I followed his advice and lapped in the camshafts.
The procedure is to use fine grinding paste on the plain journals apply finger pressure to the caps initially and start to turn the cam wheels in a back and forth motion moving the wheels about 1/4 turn every few moments. Gradually the bolts can be torqued down whilst still lapping to about 4ftlbs. Don`t continue until the shafts spin free, stop when they will spin about 1 turn with 1 finger,because they free off slightly when the head is torqued down.Finally don`t forget to wash off every trace of grinding paste or it will destroy the engine in a few seconds. We tried our 426 this weekend after carrying out the above and the difference is amazing, the bike just wants to keep revving and is much crisper off the throttle.
I would like to know if anyone else has had this experience.
Regards, Kevin.