Z1000j speedo bounce.

[warren3200gt]

Hi guys, i have speedo needle bounce. Found this thread and will check out the drive. viewtopic.php?f=4&t=47160
I haven't taken the speedo off the bike but was wondering if these electronic speed's have dampers in them like the mechanical ones do?

[Al]

They have a moving coil / magnet arrangement for the needle, nothing like the liquid friction 'clutch' of the older clocks.
Is it registering a speed when moving along and bouncing at different speeds or registering nothing but bouncing up from the zero needle stop?
If its the latter, it very likely that the pegs on the drive ring are not engaged with the speedo Hall sensor.
If its the former i would say its likely that it is only partially or intermittently engaged.
Easy to check as per the other thread if you take the sensor unit off the front axle and by hand, or with the use of the drive ring, spin the sensor and you will hear the odometer and see the speedo moving. If you have a drill with a keyless chuck, it fits nicely into the drive ring when its installed in the sensor unit.
Select drill not hammer.

AL

[warren3200gt]

Thanks Al. It's the former, it reads but bounces +/- about 10mph either side of true speed. . I've taken the hall sensor drive out and found similar to that described in the search result thread. The drive plate had domed presumably from previously over tightening the axel. This would mean the central tube part of the drive would have been rubbing against the wheel bearing. I've straightened it and reassembled it all but not yet tested on the road.
I'm not entirely convinced that could be the issue as both the wheel drive tabs and hall sensor tangs were positively engaged so in theory the sensor must have been rotating at the same speed as the wheel.
I'll give it test tomorrow and fingers crossed.
If it's no better I'll try driving the sensor off the bike and see how the needle reacts.
Odometer seems to be behaving normally.

[warren3200gt]

I'm not entirely convinced that could be the issue as both the wheel drive tabs and hall sensor tangs were positively engaged so in theory the sensor must have been rotating at the same speed as the wheel.

Im going to retract that after pondering it for the evening.
If the central tube is touching the bearing its goining to be touching the bearing inner face which to turn at wheel rotation speed it would need to be turning the bearing inner around the axle. What I suspect is happening is the bearing inner is turning on the axel but is also dragging and slipping and dragging and slipping. Creating the needle bounce.

I'll find out when I go for a test ride!

[warren3200gt]

love it when a plan comes together. Loverly smooth needle movement.
Gotta love the power of forums.