tach trouble

[mes_423]

well ive been having tach. trouble it works when it want to then only goes to 6000rpms and then stops. now ive checked the connections there tight without being to tight, but when i was looking at the tach cable it was orange almost like rust. is that maybe my problem? :dunno:
thanks

[JamesG]

Are you sure the engine is reving over 6K?

[Kerry]

I have a similar problem with my '99.  Usually when I start my bike the tach needle doesn't move.  As long as I idle there's no change.  But when I rev it up a bit the needle pops up to 3000 RPM or so, and then registers correctly over the entire range until I start the bike again at the end of the day.

Any ideas?

[mwdbruno]

I've seen the same as Kerry on occasion.  When cold, occasionally, then tach doesn't register for a minute or so.  Once warmed up (well within 30 seconds or so of start-up   ) it kicks in and I have no problems afterward.  I figure it wasn't a big deal...but this may be an epidemic....

Lane  

[Bob Broussard]

Pull the cable off the tach and lube it.
Try some graphite or something light so the cold doesn't affect it too much.
Things thicken up when cold. The cable needs to spin freely or the tach will jump around.

[Kerry]

Hmmm.  It's not that the needle jumps around - it doesn't move at all at first, and then something "snaps" and it works smoothly and normally.

I've been thinking about this some more.  It seems like the tachometer cable either spins or it doesn't.  If it's attached correctly on the engine end I don't see that it has any choice in the matter.

But aren't both of the gauges on the GS500 of the "spinning magnet" type?  In other words, the needle isn't connected directly to the cable, right? (Like the cable is to the engine.)  So if there were something "sticky" on the needle assembly at the 0 RPM position, it might take some extra "oomph" to get the needle moving in the first place.  But coefficients of friction being what they are, the needle could move fairly freely once it got moving at all.

Maybe in Lane's case the "sticky" stuff is water-based and has a tendency to ice up.  On my bike the problem happens even when it's not cold outside, so I suspect some old/dirty grease or something.

Does any of this make sense?  I'd love to know for sure, but I don't think I'll be disassembling the tach just to find out - not as long as it's working, anyway....

[ashman]

mine will sorta float when i'm cruising on the highway for more then 45 min or so. not sure what thats about tho. Good to see u back kerry! had some questions for you about packing my bike. my buddy nd i did a camping trip on our bikes, things turned out well thanks to my net bunggie.

-ash

[crmeyer]

I had the same trouble during the really hot days in summer.  The tach would stick at 7K and would jump up to 8K.  I think that its temp related, but you should make sure that the cable is seated right and well lubed.

[Bob Broussard]

You can take the tach out and lube the area where the cable fits in.
Hold it upside down so the lube gets up in there.
That might help :dunno:

[BigRedMonkeyButt]

On my 93, I had the tach cable kindof unscrew from the case - from the vibration.
On the case side is a gear that turns the tach cable.
Letting it unscrew for some reason snapped the little gear.

So, make sure the cable is tight at the tach, and at the case.

If they are, lubing them might be a good idea.

When you take it off to lube it, take a look at your drive gear and make sure it looks ok.

As I recall (and it's been 3+ years), but I think it looks like a small piece about 2-3 inches, with a gear on one side and a flat head screwdriver style on the other.  Careful with it.

[The Buddha]

Well take it off the housing... its easy - take off the 2 acorn nuts, and the cable and the odo reset knob if its the speedo and it should lift out... but lift slowly and undo the bulb and then set it face down and lube that cable opening ... one of those cable lube or 0 wt synthetic oil would be great. On my bike I opened the ring and set the mileage etc but forgot to clean the inside of the glass... Dumb me. Anyway its easy to lube it.
Cool.
Srinath.