(Gixx1300R @ Jul. 08 2007,11:48)
(bigoltool @ Jul. 08 2007,11
) This is just a question (more or less) so don't aim the flamethrowers at me just yet. I believe Suzuki designed this part simply as a guide for the cam chain, not as any kind of tensioner. As I understand it (and I can't say that I truly do) this things job is to assure that the inertia generated by the top run of the chain does not generate any unwanted fluctuations in cam timing or undue stress on any of the valvetrain components. It appears as though the part was originally designed to flex to some extent as no piece of sheet metal would have the strength to truly remain stationary in this situation given the mounting points and materials already discussed here. For the part to fail there could be other issues at play here. Could the valve train had some contributing factors that caused this. Stretched chain, bad tensioner etc? I know APE sells a Roller chain conversion kit for the Busa that is purportedly much stronger than the stock Hivo chain. Sounds like the stock chain may be a suspect component. Schnitz website even goes so far as to recommend replacing it every 15K! Here is some good reading on the subject.
http://www.hayabusazone.com/rcconversion.html
I'll run along now.
The Top cam chain guide is under little stress. The Cam caps hold down the cams as they turn. Harmonics from the cam lobes cause major vibration on the top of the motor. At 10,000 rpm the cams spin 40,000 rpm. The top guide is not designed to flex. The 2 lower cam chain guides are flexible,Suzuki reengineering the 2 lower guides in 2001 to flex and did a Cam Chain tensioner recall to add the flexible parts to the 99-00 Busas. If the top guide were to flex it would be possible for the chain to jump a couple of teeth on the sprockets which would cause the pistons and valves to hit. It is possible to remove the top guide completely from the Cam chain system but the ratchet on the tensioner needs to be machined to do so. Engine builders that do this use a manual tensioner so that the inertia on the chain does not ride upward when the camchain hit the apex of the cam chain sprockets.