TOPIC:

loudhvx wrote: This question must come up at least once a year, and I still can't remember the conclusion.
I'd hate to speculate too much. Maybe Steell will see this and can chime in.

I couldn't find anything definitive, but someone over at the KZ400.com site believes the taper on the end of the crankshaft might be different, so the later 750 flywheel/rotor might not fit the earlier B models. He didn't seem to be certain though, so a guy could find a flywheel cheap & give it a try. ??? Also, the flywheel bolt is different, but that may not be a problem. ???

Steve AZ wrote: Ok, so I understand this correctly, keep the existing system, no good way to minimize the wiring of the separate regulator and rectifier, and the whole system is OK if I switch to all LED's. Correct?

The only reason you would need the permanent-magnet charge system is if you wanted to get rid of the battery (though it sounds more like this is not an option, based on what Martin found). Otherwise, if the excited-field charge system is working properly, it would be the preferred system, even though it is a little more complex. This is especially true if you are reducing the load on the bike, because then you won't be wasting crank power as heat, as would happen with the P-M system.

If you keep the existing E-F system, you don't have to convert to LED's, but you can if you want to. The real advantage of the E-F system is that it can handle a wider range of loads with more efficiently. In my experience, the E-F system had much better output at lower RPM's compared to the P-M systems, so I wouldn't bother with the LED's. It would be more for looks. I find the LED's don't quite have the brightness during the day, particularly when you look at them off axis.

That Oregon motorcycle parts reg/rec will slightly reduce the wiring clutter, but not enough to warrant buying it if your current system is working properly.

If you suspect the system is not working properly, then I would perform the tests in the factory service manual.

martin_csr wrote:

loudhvx wrote: This question must come up at least once a year, and I still can't remember the conclusion.
I'd hate to speculate too much. Maybe Steell will see this and can chime in.

I couldn't find anything definitive, but someone over at the KZ400.com site believes the taper on the end of the crankshaft might be different, so the later 750 flywheel/rotor might not fit the earlier B models. He didn't seem to be certain though, so a guy could find a flywheel cheap & give it a try. ??? Also, the flywheel bolt is different, but that may not be a problem. ???

Ah, maybe it was on the twins site that I recall this topic, which explains why I couldn't find it here. Different taper would be a no-go.

martin_csr wrote:

loudhvx wrote: This question must come up at least once a year, and I still can't remember the conclusion.
I'd hate to speculate too much. Maybe Steell will see this and can chime in.

I couldn't find anything definitive, but someone over at the KZ400.com site believes the taper on the end of the crankshaft might be different, so the later 750 flywheel/rotor might not fit the earlier B models. He didn't seem to be certain though, so a guy could find a flywheel cheap & give it a try. ??? Also, the flywheel bolt is different, but that may not be a problem. ???

Yep, 76 is a definite no go (because of taper), but 77 seems to be a crap shoot. I put a later model rotor on a late production 77, but others with early production 77's said it wouldn't fit.