speedo problems

Hello kzrider forum posters

I'm back with yet another question after a year and a half.

I have recently replaced both of my tires on my 78 kz650b which went very smoothly i must say. However when I got back on the road my speedometer was no longer working properly. It won't register the correct speed and the needle jumps around like a kid with ADD. It seems to me that something isn't connecting right. However I'm pretty sure that the cable is in correcly, and that do to this being the first time I've ever taken the front wheel off i am sure I've made some minor mistake in putting it back on.

Any advice out there for me?

Clearwind,

While I don't have any help with resolving the problem, I do have advice about what to do until you do solve the problem. Disconnect the speedometer if you need to ride the bike for anything besides diagnostics and repair. The jumping around can cause damage to the speedometer needle or other parts. I have a broken CBX speedometer needle due to it jumping around. I wasn't happy with that result!

I'd say disconnect the speedometer cable and pull the inner one out, check it for broken strands(it's made up of twisted wires)and re-lube it with some light grease(I like using moly grease)re-install it and try again.

Make sure the gear box on the front axle works when the front tire is spun.

MFolks wrote:

I'd say disconnect the speedometer cable and pull the inner one out, check it for broken strands(it's made up of twisted wires)and re-lube it with some light grease(I like using moly grease)re-install it and try again.

Make sure the gear box on the front axle works when the front tire is spun.

Plus, be certain that both ends of the outer cable are screwed on snugly, it may have worked loose at the speedo end. Don't use pliers, finger tight is enough.

I had a similar situation and it ended up being a broken shaft on my speedometer drive gear. It was working fine and started jumping one day before it quit all together.

If problem is a new one, I would look to speedo drive unit and verify that 1, the outer drive is properly seated in hub, and 2nd the inner worm gear is still seated against front of housing. Your' bike makes it easy to check with wheel removed as axle/spacers/drive can all be assembled on the bench and cable drive blade checked for motion/slack before fitting wheel. luck G

Take a look at the speedo drive unit housing on the left side of the front axle. There is a small projection on the housing that must be positioned properly. Here's from the FSM:

"Mount the the front axle clamps and tighted the nuts loosely. The arrows on the clamps must point to the front.

Turn the speedometer gear housing so that it points to the 2 o'clock position. Be sure the small projection on the gear housing does not catch on the lower part of the left fork tube.

Tighten the axle nuts with 51 - 65 ft. lbs. torque and position speedometer housing by turning it counterclockwise until it stops.

Tighten first the front axle clamp nut and then the rear nut with 11.5 - 16 ft lbs of torque. There will be a gap at the rear of the clamp after tightening."

MFolks wrote:

I'd say disconnect the speedometer cable and pull the inner one out, check it for broken strands(it's made up of twisted wires)and re-lube it with some light grease(I like using moly grease)re-install it and try again.

Make sure the gear box on the front axle works when the front tire is spun.

My speedo does the same. At about 70mph it starts to go mad and over 90mph it is calming down. I have checked my cable and all the strands look ok. Nothing is untwisted, bent or broken. I have noted that the outer sheath made from a twisted wire ends a bit rough in the ferrule which is on the gear end. There is a little washer, which I now think might catch on the rough end of the outer sheath, catching and jamming the drive wire a bit. I greased it all up and added another washer for the first washer to run against. Hope this helps, if not I might need to invest in a new cable.

My fix did not make any difference. The speedo needle is still jumping between 60 and 100mph when I do about 80mph. Has anybody any better idea what else to do before I go and buy a new cable?

You can take your cable off and slide the cable part out of the casing if it is damaged in any way you need a new one....my speedo jumps around a bit too the faster i go the more it jumps around at 130kph it jumps between 125 and 135. I put some extra foam under the gauges to reduce vibration(local motorbike mechanic suggested it) and it helped a lot. still jumps a bit but I've learned to live with it.