Unbalanced geardrive '86 700 ?

Recently needed to remove both heads from a 30k mile VFR 700 engine to recover a wayward nut. Spinning the geardrive mechanism by hand , it seems to ALWAYS coast to stop in a consistent position, a rotational imbalance i find surprising from Honda. No obvious reason why the unit couldn't be balanced ? :topsy_turvy::topsy_turvy:

 

With a 180 degree crank and the half-speed mechanism of cams, it would seem likely that the cam lobes would be 90 degrees out from each other so naturally unbalanced anyway. Presumably with a 360 degree crank (VF and ST engines) the lobes would be balanced. A little imbalance in the cams would be trivial as their rotating mass is tiny compared to the crank/rods/piston.

 

I always place a very high value on your posts, Terry, for accurate and insightful info, but there's alot of weight within the geardrive, far more than unbalanced cam lobes, which i agree are insignificant.

 

Mate, I don't know everything! It was just a semi-informed opinion. It seemed to me that all the gears would be balanced more or less by design as they are all circular, but the cams in the VFR series would be significantly unbalanced simply due to the lobe positioning.

 

GREEN dot shows lightest spot of the gear assembly

 

I am gonna guess it is the spring mechanism in the split gear.

 

so they coulda manufactured the large gear to balance the assembly maybe or balanced the split-gear section doncha think ?


eaceful:

 

those geardrive sets pictured in your post are substantially different from the ones on an '86 700

 

Yeah, good point, they are from a 5G I think, with the side mounted gears rather than the central drive on the 86-97 750's. The cam lobe position would have to be the same as the crank phasing is the same on all the VFR's (but not the VF or RC30/45 which all use a 360 degree crank).