Instruments problems on an '84 GS750EF

[Anonymous]

New bike for me, still working on making it run the way I want it to as evidenced by my posts in this forum so far.
Bike just passed 59000 KM.

Instrument cluster is giving me some problems... it's cracked and has been taped up, so moisture inside may have or may be causing these, but I'm open to other options as well:

1) Fuel gauge doesn't function 100%. It only ever goes to a little past 1/2 when I fill 'er up to the brim. BUT, it does seem to go down at an appropriate rate... when I flip to reserve it's near the bottom, so it's hard to tell. Sticky floaty thing maybe?

2) Tachometer has a hard time up past 5500 rpms. Even when I know the bike is revving around 9 - 10 near the red line, the tach still says 5500-6000 and kinda bounces around a bit like she's trying to get up there. No idea what might cause this. This happens when I'm accellerating as well as holding a steady throttle.

[Bolder Biker]

I can't answer your question on the fuel gauge but I have also experienced the tachometer problem that you have described. This appears to be a common problem with Suziki electronic tachs of that era. "KZ" (Karl from Sweden) wrote a "Tips and Tricks" post about a year ago on a solution that he found for the problem. This solution involved replacing the 2 capacitors on the tach's little circuit board. I tried this approach and it didn't cure the problem on my 1983 GS750ES' tach, but apparently it does work for some. I suggest you do a search on the "Tips and Tricks" forum using "KZ" as author as the criteria, and you should find Karl's excellent post.

I did finesse the problem to some extent by calculating the "red line speed" for each of the first 4 gears, and then marking these speeds with thin red pinstripe tape on the clear plastic "glass" face above the speedometer. Ultimately, the problem was solved when a motorcycle dealer that I know gave me an almost new tach when he was clearing out his NOS for old bikes. The normal replacement price for the tach/speedo combo unit is about $560!

BB

[Anonymous]

fuel gauge

Can't help with the tach but to check the fuel gauge get a piece of wire, coathanger or whatever, cut it about 12"? long put a small bend @90? 1/2" long or so in one end. Reach thru the fuel neck and push the float to the top and the gauge should read full, let it go and it should read empty.
If it does'nt read correctly remove the two wires going to the sending unit and join the two wires that go the the gauge, this will cause the gauge to read full, when you disconnect it, it should drop to empty. Should this work get hold of a volt meter and set it to the lowest resistance range, if I remember correctly empty was 0 ohms and full was 100 ohms approximately.....Mike

[Anonymous]

Red-line Speeds

I did finesse the problem to some extent by calculating the "red line speed" for each of the first 4 gears, and then marking these speeds with thin red pinstripe tape on the clear plastic "glass" face above the speedometer.

What are the red-line speeds for each gear? I just bought a used 1983 GS750ES with an insturment cluster from an older model. The tachometer is mechanical so it doesn't work...

Also, does anybody know a trick to get a mechanical tachometer working with the electronic sending unit on the 1983 GS750ES?