Speedo/Tach Ratio?

[TK685]

Hey everyone, I just recently bought an '83 GS1100 GL as my first bike. However, some kids broke in the glass from the gauges. I am looking to replace them and I was curious if anyone knew what the ratios were or the information I would need to know to get the correct aftermarket replacements.

[TheCafeKid]

All Japanese bikes use the same speedo gear ratio..so you're good with whatever there. Tach ratio will depend on the size of bike you get the gauges off of. I would look for a same displacement bike at very least...but you would be best served to find some GS gauges from the same or near size bike. Too bad ya didnt catch me a few weeks ago, i had a set of your gauges i got rid of. Check fleabay...

[TK685]

Well I am looking for an aftermarket gauge that is fairly simple, not the same ones I had. Do you by chance know the numbers of the displacement or where it'd be easiest to find them. Or also do you know the ratio numbers?

[TheCafeKid]

Your bike is 1100CCs displacement. Well prolly not exactly that but that's what she's designed as. I think the speedo ratio is 2240:60 ALL Japanese bikes use this ratio. The tach ratio will differ from bike to bike, as red line is slightly different on them. Check OldBikeBarn for a universal tach and speedo. You looking for mini's or something? Most likely you'll find aftermarket Tachs to be electronic, so it doesnt matter what the gear ratio is as they run off your coils i believe...

[Suzuki_Don]

Sorry to bump in on this topic, but it is sort of related. I have purchased a 1980 Suzuki GS850G set of gauges to fit on my GS550B. They will physically bolt on. And I know I will be missing one gear selector position as my bike has 6 gears and the 850 only has 5. But I have done a trial run with the gauges connected temporary and all gear positions work and light up on the dash except 6th and it is just blank. So no problem, when I'm in top gear there will be no indication (so I'll know I'm in 6th).

Anyway will the ratios for the speedo and tacho be OK for the 550. The reason I ask is that the tacho drive for the 550 is from the rocker cover and the drive for the 850 is from the cylinder head. So wondered if there was any difference in ratio. Also the redline for the 850 is different from the 550.

Any help out there would be appreciated.

Cheers Don

[SPARKSS]

Hey everyone, I just recently bought an '83 GS1100 GL as my first bike. However, some kids broke in the glass from the gauges. I am looking to replace them and I was curious if anyone knew what the ratios were or the information I would need to know to get the correct aftermarket replacements.

Hi there TK - If your existing gauges are otherwise in good shape except for the glass, why not tear 'em down and replace just that - at least while you try to source other units - nothing ventured nothing gained.

Been reading the replies here with interest......Bikes like ours (and many others) drive the tach off of the camshaft.......which in any 4 cycle engine rotates 1/2 of crankshaft RPM. What the drive and driven gear ratio of of THAT is the missing information. If you have access to a reflective or phototach (or even a mechanical machinery tach) you could chuck a cable (or make a small drive tang) and drive the tach with this as a test......measure how much input rpm (chuck) is required for indicated rpm - this will provide the missing info. If you have the mechanical machine tach it'd be more accurate to measure the actual drive socket on the cam - a word of caution - most of these kinds of tach typically show 3500 rpm max and this will require that you also, simultaneously (or alternatly) measure the engine crank rpm (perhaps at the ignition end) to determine the drive ratio.

For what it's worth.

[bwringer]

So, has anyone found those rotten kids yet? :shock:

Or worse -- were they yours?

[8trackmind]

Well I am looking for an aftermarket gauge that is fairly simple, not the same ones I had. Do you by chance know the numbers of the displacement or where it'd be easiest to find them. Or also do you know the ratio numbers?

Tach ratio is 1:4.

[TK685]

Thank you to everyone who gave some info, it was very useful. As for the kids who broke out the glass... no one was caught. The bike was not in my possession when it happened, the bikes first owner had it put away for many years after falling off of it when drunk and his wife put the end to his riding days. So while it was in storage some kids found it and broke the glass. Not a big worry to me as I know I would like to replace them anyways. Also does anyone by chance know of anywhere I could find an exhaust that is a 4-into-1 with a cannister? I found a mac exhaust but I haven't heard much good about mac. I could only really find a vance hines exhaust that was a megaphone

[TheCafeKid]

Thought i just read a thread touching on this very thing...I seem to recall the advice being to try out a GSXR pipe set, and i also seem to recall having to maybe tweek the head pipes a bit and possibly having to do something about clearance underneath or in front....Guys? Anyone else know more about this??