Tach...

[zx7]

Another question...

After driving for about 20 min or so my tach needle starts bouncing around within a 750 rpm range...what could 'cause this? Are there some teeth in there that are possibly worn and it starts to slip? It does seem to happen at higher rpm (highway speeds), but not really during acceleration...more at a steady speed...

Any ideas...?

Thanks.

 

[DimitriT]

It either the cable or the tach.

Here's some things to try:

1. clean and lube the cable
2. reinstall and make sure its properly routed with no bends

if that doesn't do it...

3. pull the tac unit and put a few drops of 3 in 1 oil into the
cable receiver - let it soak in over night (you may have to
keep it balanced so the receiver points up)

if that doesn't do it...

4. open up the tac and clean out the drive mechanism with WD-40
or brake cleaner (be very careful not to get solvent on the face
as it may remove the paint). Reoil with 3 in 1 and close it up.

Step 4 requires you to open the unit up which is tricky and involves
uncrimping the retaining ring and recrimping it. Hopefully one of the
earlier steps will do it for you.

I've also found that vibration sometimes causes the needle to wobble.
If the problem happens at a specific RPM range, you may try replacing
the rubber cushions which isolate the cluster from the triple tee.

 

[zx7]

It either the cable or the tach.

Here's some things to try:

1. clean and lube the cable
2. reinstall and make sure its properly routed with no bends

if that doesn't do it...

3. pull the tac unit and put a few drops of 3 in 1 oil into the
cable receiver - let it soak in over night (you may have to
keep it balanced so the receiver points up)

if that doesn't do it...

4. open up the tac and clean out the drive mechanism with WD-40
or brake cleaner (be very careful not to get solvent on the face
as it may remove the paint). Reoil with 3 in 1 and close it up.

Step 4 requires you to open the unit up which is tricky and involves
uncrimping the retaining ring and recrimping it. Hopefully one of the
earlier steps will do it for you.

I've also found that vibration sometimes causes the needle to wobble.
If the problem happens at a specific RPM range, you may try replacing
the rubber cushions which isolate the cluster from the triple tee.

Thanks! I'll give those steps a try...one question though - what is 3 in 1 oil?

Thanks again!

 

[Dave8338]

A light weight oil that's been around from the begining of time. (Now I know I'm getting OLD) \\/ Marvel Mystery is about the same thing.

 

[zx7]

A light weight oil that's been around from the begining of time. (Now I know I'm getting OLD) \\/ Marvel Mystery is about the same thing.

Haha! Aren't we all...:-D

 

[Mark whiz]

If your tach is cable operated, disregard these comments, but if it is electronic there might be another issue. The cables that feed one of the coils also sends a pulse to the tach which tells the tach needle where to go. Mine ('85 GS700ES) acted like yours for several years. I had to replace the Ignitor box for the ignition recently to get it running right, and miracle of miracles - the tach started working correctly.

I sure wouldn't spend the money for an ignitor just to fix the tach..............but if in time the bike starts running "ratty" - the Ignitor is the first thing to check.

 

[Nessism]

Bouncing needle is classic symptom of a sticky tach cable. Remove the cable from the bike and pull the inner cable wire straight out using some needle nose plyers. Clean up the cable, both the inner and the outer casing, relube, and put the cable back in. Replace the cable if it looks worn or damaged. Should take care of the problem.

 

[zx7]

Bouncing needle is classic symptom of a sticky tach cable. Remove the cable from the bike and pull the inner cable wire straight out using some needle nose plyers. Clean up the cable, both the inner and the outer casing, relube, and put the cable back in. Replace the cable if it looks worn or damaged. Should take care of the problem.

Do you mean disconnect at the tach not the engine or both...? Is it similar to the speedo cable? I had to replace the speedo hub piece for that at the wheel this spring.

Thanks!