Tach noise?

[The1970's]

I'm not really sure what section to post this question in but here goes: 78 GS750 with factory gauge assembly. Something in the front end has started making a fast vibration sound, almost like a buzzing sound. It does this intermittently when at higher RPM's. It seems to get worse when under hard acceleration which leads me to believe it is the Tach. A while back I dripped some oil in the cable attachment point with the gauge flipped over and it seemed to quiet down for a little while. Recently the tach started reading way wrong and not really going over 4K I ordered a new cable and that fixed the functionality but it's still making noise. Does anyone know of a way to lubricate the tach or fix the issue? Any idea what else could make that noise?

[fastbysuzuki]

There is someone who had the same problem as you here http://www.thegsresources.com/_forum...ght=Tachometer
There was a good tutorial of how to get into the gauges but the links are not working.

[The1970's]

There is someone who had the same problem as you here http://www.thegsresources.com/_forum...ght=Tachometer
There was a good tutorial of how to get into the gauges but the links are not working.

I should point out I have had the gauge apart once before. It's been a while but I believe I took it apart to attempt to fix this the first time around. There didn't seem to be any dirt in the gauge and everything moved freely. Maybe I'll pull it apart again. Is there anything I don't want to get oil on inside?

[Rijko]

I'm not really sure what section to post this question in but here goes: 78 GS750 with factory gauge assembly. Something in the front end has started making a fast vibration sound, almost like a buzzing sound. It does this intermittently when at higher RPM's. It seems to get worse when under hard acceleration which leads me to believe it is the Tach. A while back I dripped some oil in the cable attachment point with the gauge flipped over and it seemed to quiet down for a little while. Recently the tach started reading way wrong and not really going over 4K I ordered a new cable and that fixed the functionality but it's still making noise. Does anyone know of a way to lubricate the tach or fix the issue? Any idea what else could make that noise?

First you need to find the source of the noise.
May be the gauge, cable, speedo drive at the wheel, bearings.
Disconnect the cable from the drive at the wheel.
Spin the cable using a drill and see if the gauge starts to whine.

If not, re-connect the cable to drive and disconnect from the gauge
and see if the sound is still there.

[Big T]

First you need to find the source of the noise.
May be the gauge, cable, speedo drive at the wheel, bearings.
Disconnect the cable from the drive at the wheel.
Spin the cable using a drill and see if the gauge starts to whine.

If not, re-connect the cable to drive and disconnect from the gauge
and see if the sound is still there.

Your sequence is correct, but the tach doesn't drive from the wheel

Disconnect the cable from the tach, take it for a drive, see if the noise is gone
Use a zip tie to hold the cable from slipping down

[Rijko]

my bad, was trying to offer alternative sources for the sound and forgot about the main suspect

[The1970's]

First you need to find the source of the noise.

So here's where i'm at: I disconnected the tach cable from the gauge and zip tied it, went for a ride and it was still making the noise. I pulled over, took the speedo cable off the gauge and it still made the noise. When it does it I can put my fingers on the glass of the gauges and it makes no difference. When I got back it was nice out and I decided to wash the bike. Afterwards I went for a short ride to dry off the rest of the bike and the noise seemed much worse. This may have just been a coincidence but figured I'd point it out. Any other ideas?

[fastbysuzuki]

Have you tried putting a jack under the front of the engine just to lift the front wheel off the ground so you can spin the wheel and replicate the noise? Check for dry wheel bearings, play in bearings, noise coming from speedo drive. disconnect and remove the inner cable from speedo just in case there is a problem with the outer sheath of the cable likewise with the tach cable.

[The1970's]

Have you tried putting a jack under the front of the engine just to lift the front wheel off the ground so you can spin the wheel and replicate the noise? Check for dry wheel bearings, play in bearings, noise coming from speedo drive. disconnect and remove the inner cable from speedo just in case there is a problem with the outer sheath of the cable likewise with the tach cable.

I just put a new tach cable on so it shouldn't be there and I also recently replaced the front wheel bearings. The noise started before me replacing them and continued after. I will have to check the speedo drive but I don't remember it making any noise when I spun the wheel after I did the bearings.

[The1970's]

I am now sure that the noise is coming from the tach. I can move the tach cable towards the headlight a little while riding and it goes away. One thing I'm not sure of is whether the dash assembly mounts on the top or bottom of the tabs on the tripple tree. The cables seem like they're being bent too much by the headlight bucket if I put it below, which is where I think its supposed to go. I also found a missing rubber grommet between the gauge mounting bracket and the tach. I though for sure that was the problem but I put in a few layers of an old tire tube and it stayed the same. Anything else to check? Otherwise I'm going to be pulling the gauge back apart and greasing the insides

[The1970's]

Just wanted to post the solution I found to the issue here. I was frustrated for at least 2 weeks going back and forth between the tach, speedo and headlight to figure out where the noise was at. As it turns out it was the fuel door vibrating against the tank the whole time. To test it I just put some pieces of rubber inner tube underneath and it solved the problem. I am now ordering the proper grommets as mine are crushed and wore out.

[chuck hahn]

16 is the cushions that go on each side of the tank right under the front of the lid.

https://www.partsoutlaw.com/oemparts/a/suz/50d3ff87f8700230d8b4df93/fuel-tank-gs750c