670 and B gearbox?

[Bluebird19kf]

Could you use a b gearbox with the 670 95hp engine of do you have to go to the c or e box?

[jrthomas]

As I remember it, Rotax says a B-box is ok up to a 582. Anything larger they recommend a C-box.

[jrthomas]

I think the C is supposed to be a much better gearbox than a B. I had a B on a 503 CGS Hawk. I had to have it rebuilt. I don't think it had too many hours on it at the time, maybe 200 or so. The bearings went bad. I had a nice, smooth 3 blade Ivo prop and I ran Amsoil gear oil so I don't think anything I did caused it to wear prematurely. I suspect that a B-box would be marginal on a 582. I had some buddies that had B-boxes but I don't remember anyone else ever having a problem with them. Guess I'm just the lucky one.