82 GS1100E Speedo project

[Guest]

I have an old post here with my 82 GS1100EZ resto-mod project, but I can't find it. My bike has a GS1150 forks and fender, GSXR1100 wheels and calipers, and SV650 rotors.
One of the very last issues I have with the bike is the speedo is way off because I have a smaller front wheel than stock and I'm using the original GS1100EZ cluster and hub-drive. It's also a 85mph speedo. So it's basically indicating 85 (pegged) at a real speed of 70mph. I took a paint pen and put ticks on the glass for aprox speeds gathered by using my GPS, but I'm ready for another project on this bike, and I want to do it right.

I could buy an '83 140mph cluster, but I'd still have an error because of the smaller front wheel. The other option I've considered is a different wheel drive assembly from a bike with a 17" front wheel (and an 83 speedo.) Not sure if all that will work, or if it's the path of least resistance.

What I'd like to do is get a cable adapter to lower the cable speed by 50% and create new gauge faces that go to 140mph. It just so happens that the kph tick marks are exactly 1/2 the actual speed in mph. Ex: 50mph real speed = 100kph indicated. So I already know where the tick marks should be.

So I've been reading up on how to make your own gauge faces, and both for you and me, here's a record of what I've read. Many, many great ideas and very creative methods here:

These are directions to make Miata gauge faces:

http://revlimiter.net/mods/gauges.php

This is an example of making a Smart Car faceplate:

http://www.cubefx.com/smart/speedo/

XS650 "slow - med - fast - Oh ****!"

http://www.xs650chopper.com/2009/11/how-to-refresh-an-old-speedometer/

Cool white ones for a GS1000.

http://www.thegsresources.com/_forum/showthread.php?t=130920

How to open the Tach:

http://www.thegsresources.com/garage/gs_inside_gauges.htm

spider removal from Tach, and interesting way to get inside; even on a GS1100E:

http://www.thegsresources.com/_forum/showthread.php?t=119214

Maxi-Products 2:1 speedo adapter- exactly what I need if they were still around:

http://www.thegsresources.com/_forum/showthread.php?p=1624549&highlight=maxi#post1624549

Here's a ratio adapter that I found online, but not sure if the cable connectors are universal.

"This GM / Dodge / Ford speedometer ratio adapter will slow your speedometer reading down 50%."

So after all that, I have a couple questions for y'all:
1. Is there an easier way to do this? (w/o just using a digital bike clock)
2. Are all speedo cables the same? (Suzuki, Honda, GM, Ford, etc. - I can't imagine this is true)

Thanks in advance,
-Kevin

[bbjumper]

I have a similar issue with my "G". The original cluster was damaged beyond repair by the PO. I have not been able to find a replacement that is accurate to less than a 5 mph error. No big deal, it just bugs me plus it's an 85 mph speedo.

The digital clusters available by Acewell and others use a magnetic pick up on the front wheel like a bicycle, they can be programed for the tire size and your not limited to 85 mph. I would do that in a second but like the stock look.

Cheers

[CivilRock]

I think they all have a 8-10% error, even new bikes. Why? is a different subject. But you'll often see race speeds reported as "indicated" with the assumption of a gross gauge error factor.

I too am not ready for a modern replacement, but an elegant fix for what I have.

-Kevin

[bbjumper]

If you come across something I would like to hear about it .

Thanks,

Brad

[CivilRock]

I was so interested in starting this project that I left work early and started tearing apart the cluster. I thought about creating a new tach face to match, but after I broke the speedo needle off, I don't want to do any more damage. I even used the fork trick, and it just wasn't going to come off the right way. But I did get the dead spiders out of there!

It's much easier to just take a screwdriver and slowly pry off the lens cover than cutting the plastic and gluing it back together. This is a picture of the tachometer bezel being pried off with a small screwdriver. Should take about 3 min.



Here's basically what my speedo looks like sans needle



I took out the stop post (pin at 85mph) and scanned it into my computer using a free image manipulation program called Gimp www.gimp.org



It's a very deep program, and pretty much everything that a $200 photoshop program is, but still, you can spend 20hrs learning how to use it and get the results that you want. The trick is to use layers for everything, then change the opacity of layers so you can see what's below. The first thing I did was print out the image that I scanned in to make sure that it prints it the same size. I don't want to spend 20 hours doing this and then battle another 5 hours getting the size right.

But this is pretty much what I'm going for, and surprisingly this is only after about 2hrs of fiddling with it. And I am a total self-taught novice. I'm using about .001% of this program's potential.


I'm going to get some clear plastic sheets for the printer at work, its a laser jet, and probably create 2 layers of the "transparencies" with the color and more black out, then 1 paper layer on top.

Now I just need to figure out how to slow my speedo cable down 50%.

-Kevin

[CivilRock]

So the only ratio converter I found is a big box that takes out about 6" of speedo cable. It's made for cars, and I don't really see a good place for it. It is a fix, I guess, but I'd still have to create a new face for my existing speedo.

I started thinking that an easier route would be to use a '86-88 GSXR1100 mechanically driven speedo. It goes up to 170mph? and it should already be set up for a 17" wheel. It would be extra cool if I could make it fit inside the GS cluster housing, but it's not like I've modified stuff before?

I'm going to start making some offers on these gauge sets and see if it works.
It looks like almost exactly the same size face at least. It would make sense, since so much of this stuff is easily adaptable from year to year.

[CivilRock]

Just bought this damaged cluster for $29 on Ebay. Speedo looks like the only good part. It's a chance, but I'll return it if it's not even close to working.
If this works, apparently my stock motor GS1100E will be able to go 175 mph before it's "pegged".

[CivilRock]

Got the used GSXR1100 speedo in the mail yesterday and dove in after the family went to bed.
So the new (newer) one is a little smaller. And as I was looking around for a spacer to shim it in there, it turns out the old bezel just barely fit outside the new one, and worked perfect as a spacer to center the gauge face.

The next problem is that the body of the speedo doesn't all fit inside the old housing. There's a 90* gear out the back that's going to require some "customization" of the cluster body. I hooked up the cable and spun the front wheel just to make sure it worked, and it does. No idea if it's accurate at all, but my fastest hand spinning was just getting it up over 10mph. We'll see on that one. At least if it's not accurate, I know how to make a new gauge face and I'll have the range to go over an indicated 60mph. I'm going to do a final test drive before I start cutting the cluster body.

It totally doesn't match, but neither does the rest of the bike. I'm pretty sure I don't care that it's different, and I'm probably going to like it that way. A little more character, and probably a conversation topic.

-Kevin

Back to the workbench with the mess:


Some zip-ties, some safety wire, some creativity, and she's in!


Not a perfect match, but good enough for the kind of girls that I date:

[CivilRock]

Took her out for a test ride last night at about 10pm, and it works. It's still reading fast, and it dawned on me: It's not the speedo that's calibrated differently (I think they're all 2240:60 from this era) it's the speedo drive on the hub that's off. I'm using my original GS1100 hub drive! I happened to still have a GS1150 speedo drive that came with the front end sitting in a box and I spun them both around and counted the revolutions. The GS1100 was about 20% faster. The GS1150 hub should work. I calculated the diameter of all the parts I have to figure out what will work:

GS1100 - 110/90-19 = 26.8" diameter (hub drive I was using)
GS1150 - 110/90-16 = 23.8" (hub drive I have)
GSXR1100 120/70-17 = 23.61" (correct hub drive)

So the 1150 axle is a 15mm and the GSXR is 20mm, and I happen to have an 1150 hub drive, but it's a different cable. Should be close enough on the drive ratio. Just ordered a new 1150 cable. We'll see if that works!

Hopefully somebody can learn from my mistakes!

Side story if anyone is listening: I was out on my test ride last night with my GPS recording the route to see if the speedo was anywhere close to correct. I didn't ride the bike all winter, and only added a little gas 3 weeks ago. I took it out on the freeway so I'd get some nice 60mph constant speed and ran out of gas. No problem, I've done this 500 times before, flip her on reserve and keep going. Flicked her in reserve and kept on slowing down, down, down. Nothing. I have zero tools, it's really dark, and I'm on the side of the freeway going uphill. For the next 30 min I'm pushing this bike up a 1+ mile, 300-400' elevation gain to the gas station. If you know Portland, I'm pushing up to the Sylvan exit on Hwy 26. I'm not kidding about the uphill. Luckily one of the two stations was open and the bike started with a full tank of fuel. One more issue to contend with. Never had my reserve fail before.

-Kevin

[Katana1074]

Hi Kevin...

Did you mange to sort the speedo calibration,im currently fitting gsxr wheels
to my 86 gs1150 and would like to try and get the speedo as close as possible....

Regards

Roy

[FullThrottle82]

I have gsxr wheels on my 82'. I am using the stock gauges with a bandit speedo gear. I have checked multiple times with my gps and my indicated speed is only 2 mph faster than actual. I checked from 10 mph all the way to 70 indicated. I guess I got lucky.

[Katana1074]

I Might give the bandit speedo gear a try,should be able to get one
pretty cheap on ebay...

Cheers for that

Roy

[CivilRock]

Roy,
So the 1150 is a 16" rim and the GSXR rim is 17", but the stock 1150 tire is much taller on the rim. The difference is about 0.2" so your stock gauge/drive will work just fine. If you search the internets you can find the overall diameter dimension of different tires and verify this. The calculator I found was on a Bonneville Salt Flat Racing site. If you dig deep enough tire manufacturers also publish this data. OR, the best is if you have both wheels with tires you can set them side by side and see that they're about the same.

If you haven't found out already, another problem is that the GSXR wheel will have a 20mm axle bearing hole, and the 1150 uses a 15mm axle. I ended up using the 15mm axle with 5mm aluminum sleeves (made on a lathe). That also lets you use the 15mm 1150 speedo drive which you already have.

I hope I remember this all correctly... it was 2006 when I did the build, but the GSXR axle is a different (bigger diameter). But the point is; if you buy a Bandit speedo drive, you might have to sleeve it to fit the axle.

Mine finally works, and it's close enough to accurate. Probably as close as new bikes. It's kind of funny that it goes to 170mph, as I'm only going to use the first 1/3 of the gauge. The only problem I now have is that the odo 1/10ths work, but the miles don't move. The trip works, but the main odo is stuck on 2,199, while the 1/10ths spin correctly. Have to take it apart and see if I can fix it, or buy a better one now that I know this setup will work.

-Kevin

[Katana1074]

Hi Kevin...

i Have 4 speedo drives to choose from,gsxr1100,Bandit 1200,gs1150 and
gs1100ez...

Bike has Gsxr1100wp usd forks fitted....

After looking around a few site there`s quite a bit of difference from

110/90/16 to 120/70/17 diameter wise... might dig a bit deeper on this

i`ll give it a try anyway,

Thanks for you help

Roy

[CivilRock]

Here's the site I used:

http://www.rbracing-rsr.com/tirediamcalc.html

I also know that every tire is going to be a little different shape and the actual diameter should be a little different than the math would tell us.

But according to the math:
110/90-16 = 23.80 inches tall
120/70-17 = 23.61 inches tall

This is about 0.8% error, and well within my tolerance for accuracy. Any appreciable difference is going to be determined by the real size of the tire and not the theoretical or mathematically derived size. If this is right, you'll get more error with tire wear than speedo error.

With that being said, I'd use whatever fits on the axle and hub! Well, except the GS1100EZ one; that wheel is way bigger. The rest are essentially the same.

When I started this, I didn't understand all the dynamics that are in play. I assumed that all the hub drives were the same, and it was the speedo that had different ratios. The truth is that most of the Japanese mechanical drive speedos of this era all have a 2240:60 ratio, and it's the hub drive (or speedo drive) that needs to be matched to the wheel size to be accurate.

Hope this helps. I just realized with this last statement that I don't necessarily have to find a Suzuki speedo for my application, just one that fits in the hole. Hummmm. How important is an odometer?

-Kevin