GS1100EZ dyno results

[davel]

Just posting this in case anyone is interested in what a stock 1982 GS1100EZ with almost 40,000 miles will do on the dyno. The only performance mod is a minor carb tweek to correct the overly lean factory jetting. Otherwise stock. This along with a highly modified 79 KZ1000 are my daily drives.

Note the 41 lbft of torque at 2000rpm. Incredible! I normally only use 3rd through 5th gear on this bike. Stock final drive is 51T front 42T rear. I'm considering switching to 18T and 39T. This will put 60mph at 3000rpm in 5th. Anyone running a similar final drive on a stock 1100E?

Cheers!

[posplayr]

thanks that is interesting

[Steve]

I'm really hoping your fingers were a bit dyslexic, there. A 51T front sprocket?
(yeah, I know you meant 15T.)

The stock 15/42 ratio is 2.8

Your proposed change of 18/39 is 2.17.

That is a 23% change. Personally, I don't think you will be happy with it.

What is your goal with the change?
- Lower engine speed? You will manage that.

- Higher top speed? Probably will hit your highest speed in third or fourth, not fifth.

- Better MPG? Probably not. You will be so far down in your power curve, you will be holding the throttle open farther. You might also have to downshift on the slightest of hills.

- Easier riding? Probably not. You will be so far out of the power curve, you will have to downshift at least twice to do any passing moves.

- Longer engine life? Probably not. These engines were meant to spin.

Good luck with the change, be sure to let us know how it works out.

.

[67fire]

On last years Rally, I switched to 17/40 or 2.35 for increased mileage and lower engine speed at higher mph.
My mileage went from an average of 38 to 42 mpg.
With a passenger, I did have to start with more clutch.
Without passenger, fine.
For around town I switched to a 16/40 or 2.50.

Forgot to mention, that was on Frankencycle. Not even close to "stock."


Eric

[gs1150streetracer]

Wow
Nice post and numbers,I really doubt I would ever see a harley put numbers like that out after so many miles and 90+horse....Very nice!!!!!!!!

[trippivot]

great numbers - great

Are you going to do a dyno pull or two after the gear change?

[1100E]

Hey, that's pretty cool - thanks for posting!

[gmansyz]

gearing

I had run 18/42 with my 31327 low compression Katana. I felt it could go even taller but then it did feel like any more would become difficult to pull away from a stop. Already, I was slipping the clutch alot and idling, I was going 25 mph. Or at least it felt that way. Even was able to get 52mpg at 70 on the freeway.
G

[davel]

I'm really hoping your fingers were a bit dyslexic, there. A 51T front sprocket?
(yeah, I know you meant 15T.)

The stock 15/42 ratio is 2.8

Your proposed change of 18/39 is 2.17.

That is a 23% change. Personally, I don't think you will be happy with it.

What is your goal with the change?
- Lower engine speed? You will manage that.

- Higher top speed? Probably will hit your highest speed in third or fourth, not fifth.

- Better MPG? Probably not. You will be so far down in your power curve, you will be holding the throttle open farther. You might also have to downshift on the slightest of hills.

- Easier riding? Probably not. You will be so far out of the power curve, you will have to downshift at least twice to do any passing moves.

- Longer engine life? Probably not. These engines were meant to spin.

Good luck with the change, be sure to let us know how it works out.

.

Yes. Fingers were dyslexic. I meant 15 not 51.

To answer your questions:

Because of the exteremly strong low-end torque of this engine I never use 1st gear. It's far too low imo. Even when riding two-up.

I also feel that the engine is reving too high on the highway. When criusing at 75mph the bike is reving at 5000rpm. My instinct along with the dyno numbers indicate that this engine will comfortably pull a much taller ratio. I'd like to see 75mph closer to 4000rpm and 60 around 3000-3200. The engine makes 55+ lb*ft of torque from 3200rpm - 8500 so I'm not concerned about being "so far out of the power curve". This engine will pull top gear at idle and never makes less than 40lb*ft of torque. This is a respecable peak torque number for modern 600CC bikes.

Regarding your assessment of top speed: with the current gearing at redline (8500rpm) this bike is doing 92mph in 3rd gear, 113mph in 4th and 132mph in 5th. This engine will easily pull redline in top gear.

I realize that passing on the highway may require a downshift to 4th but right now I rarely downshift from 5th unless I'm going below 25mph.

In a nutshell: Currently, I effectively have a 4 speed grearbox because 1st gear is too low to be useful anywhere outside of a drag race holeshot. By making a rather drastic change in final drive ratio I would end up with a more reasonable 1st gear ratio and a 5th gear overdrive.

btw this bike gets 40+ mpg in the city and 50+ on the highway so fuel mileage is not a concern.

All that said, I'm not exactly sure how it will work out but wanted to check here to see if someone with an 1100E already tried it. Will definitley keep you posted.

Here is a fantastic resource for final drive changes www.gearingcommander.com

Thanks for all the responses!

[davel]

I had run 18/42 with my 31327 low compression Katana. I felt it could go even taller but then it did feel like any more would become difficult to pull away from a stop. Already, I was slipping the clutch alot and idling, I was going 25 mph. Or at least it felt that way. Even was able to get 52mpg at 70 on the freeway.
G

Thanks! Good to know. Yeah, 18/40-42 sounds good. Did you convert to a #520 chain? My regular supplier doesn't carry many options in #630. Seems to be more options when switching to a #520 setup.

[Mysuzyq]

Good numbers, thanks for posting. I'm running 18/47 (2.61:1) sprockets with a 530 chain, and see around 3500 rpm @60, which I like....negligible lack of oomph on the bottom end, a more relaxed highway ride, and average around 44mpg with 36mm CV carbs (46 with easy cruising, and around 41 mpg with hard rev-happy riding.)
Like Steve, I think 2.1:1 would be too drastic for my taste, but do let us know how it works out. I hope to have some dyno numbers after installing Mikuni RS carbs this summer....just curious as to what the bike actually puts out at the wheel.
Tony.

[tas850g]

Wow
Nice post and numbers,I really doubt I would ever see a harley put numbers like that out after so many miles and 90+horse....Very nice!!!!!!!!

HD torque number are about double that with about 75-80 hp for a '99 softtail.

Did you check air/fuel ratio's?

I dyno'd my 850 last summer.

[67fire]

HD torque number are about double that with about 75-80 hp for a '99 softtail.

Did you check air/fuel ratio's?

I dyno'd my 850 last summer.

Could you share with us?

Thanks,

Eric

[gmansyz]

Davel, I went with 530 chain. It's a little more durable than the 520 as I had planned to turbo the Kat. It was an 8:1 1327. I think the biggest countershaft sprocket you can get in 530 is 18 teeth but there may be some custom made in 19 or maybe 20. The rear is the same pattern as the Bandit and old style 6 bolt GSXR, circa 1989-1998 1100. I looked at one time befpre realizing that IF I wanted to go fast, I would better of with a new top gear. So, when I am working again and have money, I'll have a new top gear made by robinson. Along with a new, longer, outputshaft. But I did find out that the smallest rear sprocket made for that cush and a 530 chain is 36 teeth. I would say get the 18 toother for the front and a 42 is an easy rear to get. Test it out. Then try a 39 and see how it works. Maybe you want to splurge for the 36 later? Unless you want to try a 19 or 20 for the countershaft. Oh, all the GSXR's/Busa's and other Suzuki's use the same splines. Except for the '08 and newer Busa and B-King. I can only say try it and see. Also, the bikes with the radial tires roll much more easily than the old bias plys. I am slowly converting my Kat to the new stuff.
Laters
G

[blowerbike]

Davel, I went with 530 chain. It's a little more durable than the 520 as I had planned to turbo the Kat. It was an 8:1 1327. I think the biggest countershaft sprocket you can get in 530 is 18 teeth but there may be some custom made in 19 or maybe 20. The rear is the same pattern as the Bandit and old style 6 bolt GSXR, circa 1989-1998 1100. I looked at one time befpre realizing that IF I wanted to go fast, I would better of with a new top gear. So, when I am working again and have money, I'll have a new top gear made by robinson. Along with a new, longer, outputshaft. But I did find out that the smallest rear sprocket made for that cush and a 530 chain is 36 teeth. I would say get the 18 toother for the front and a 42 is an easy rear to get. Test it out. Then try a 39 and see how it works. Maybe you want to splurge for the 36 later? Unless you want to try a 19 or 20 for the countershaft. Oh, all the GSXR's/Busa's and other Suzuki's use the same splines. Except for the '08 and newer Busa and B-King. I can only say try it and see. Also, the bikes with the radial tires roll much more easily than the old bias plys. I am slowly converting my Kat to the new stuff.
Laters
G

man i gots some niceeeee vortex rear smaller sprockets for a bandit pattern(1 or 2 maybe)