Techometer spiking?

[Yngvai X]

Alright so I just passed my MSF course today, yippie! License endorsment, once my 30 days is up on my permit.

Ok anyway now that im trying to get back to the feel of MY bike.. I noticed something very wierd.. the techometer needle will spike up.. randomly. Like I noticed it when I go over bumps and speed bumps.. the needle would just bounce up to like 8 or 9 grand and then go back to the actual speed of like 4 or 5 grand.. but today when I was riding it would just randomly bounce all the way up to almost red line and back down.

So anyone know how to fix this? I assume its an electrical problem.. but then again I dont know jack about motorcycles.

[Shiv]

Well the bump part is normal I believe, the randomly spiking part, isn't.

But I haven't a clue how to fix it, sorry.

[oldschoolorange]

what kind of tach? mechanical or electronic?

[Yngvai X]

What kind of tech, mechanical or electrical? .... well its a 1989 ninja600.

sense I dont know what you mean by mech or elec i'l just tell ya the bike.

[Yngvai X]

I take that back, its a mechanical needle.

[safety-boy]

If you have a mechanical tachometer, you'd have a cable like you'd have on a speedometer. Not familiar with your bike, but on an '89 Kawa... I would say mechanical, however, the spiking sounds like an electrical problem.

Does the engine actually rev when the tach spikes? If you throttle while the clutch is still engaged, that will happen.

If the bike is doing nothing aside from the tach spike... I have _no_ idea!

If you get behind the fairing to the back of the tachometer, it should have an aluminum screw-down (my wife's 2004 Ninja 500-R has the same connectors as my old 1986 454 Ltd). These tend to get loose. Might not be the problem, but worth looking at. If you don't have these, chances are you are on an electroning tach.

Hope this helps somewhat. I'll look at the specs later on your bike and see what I can see.

--Dave

[sharpmagna]

Tachs normally feed off an electrical signal from your engine to tell you what RPM it is running. I'd say you probably have a short in the system somewhere. Every time you go over a bump, the loose wire may move and give you a wrong reading. When it gets smooth again, everything is honky dory. It seems the short or loose wire is getting worse as it is spiking periodically now.

If you can get a hold of a service manual for your bike, you can trace and find the wire that your tach is tapping into. Hope that helps.

[Yngvai X]

Yeah when I hit bumps and speed bumps and what not like that, it jumps up as high as it wants to, then comes back down slowly to the right rpm im riding at. But it does not rev the engine when its just bouncing off everything, I tried pulling the clutch in and revving it while im moving to maybe loosin up the needle or something (basically nothing even worth doing, just hoping it might do something) to try and make it work better.

BUT I will go look at that to see if theres a short or the wires are maybe damaged or something.

Thanks

[oldschoolorange]

run the engine then start wiggleing wires and see if that does it, If it is a mechanical tack I would suspect a prob with the actual tach its self

[safety-boy]

I looked up the tach on CycleTrader.com'sCycleTrader.com's parts search (don't bother, the image was not helpful). Although, it looked like a mechanical tach, as there appeared to be only a few bolts and cable going to it. Nothing looked like an electrical connecting block. Again, not easy to tell.

I would really doubt a Kawa from the '80s would have a non mechanical tach. They are pretty low tech - the John Deere of motorcycles. Could be the cable, but more likely one of the bits on the end of it

You might look for a Clymer's guide on ebay. they are pretty good shop manuals, and Kawas are extremely easy to work on - especially older models.

--Dave