GS 1000 ST weight saving program

[John Kat]

I decided to apply a weight saving program to my GS 1000 ST.
The goal is to keep the look as close as possible to original but where possible use GSXR 1st gen components
So far I've done the front end and the savings are as follows:
Front wheel with disks, tire and spindle: 11.9 kg vs 14.3
Front fork complete: 12.5 kg vs 14.3
Front calipers: 2.5 kg vs 3.3
Sub total front end: 26.9 kg vs 31.9 or 5 Kg saved

Exhaust Kerker 4 into 2 estimated: 8 kg vs 11.6 or 3.6 Kg saved

Rear wheel with disk and tire:13 Kg vs 15.5 or 2.5 Kg saved

So far 11.1 Kg potential saving

I will have to include the front mudguard and the dashboard when I measure them.
Going to a 530 chain will help further.
The rear caliper will shed weight also.
I'll also use an GS 1100 swingarm but I'm not sure it will save weight?
Here's what it looks like so far.

 

[sharpy]

here is ure swingarm answer...

 

[John Kat]

here is ure swingarm answer...

Good news
I wonder how much could be saved with CR type carbs?
An expensive saving for sure...

 

[sharpy]

that be more like a dead weight saving. Middle of bike but a good set of 33MM smoothbores are good for 8-10Hp. Been told ten pounds of weight on a bike is equal to 1HP

 

[boingk]

Seeing as you've saved 7.5kg of weight from your unsprung weight alone(!), I think you'd already find her drastically different to ride. Unsprung mass has a far greater effect than centralised (sprung) mass. Good job!

I'd look at removing the airbox and replacing with a good set of pods. This saves a large amount of weight (3~4kg) on these bikes and will also increase power. Another step would be to use a LiFePo4 ('Lithium') type battery to save even more weight - a quick reference to here:

http://www.ssbpowersport.com.au/tabid/241/mode/showbatterytypes/btsid/32/default.aspx

sees you needing an LH14L-BS, throwing out over 400CCA at 12v and weighing a scant 1.1kg. A Yuasa 14Ah lead-acid battery weighs around 4kg with acid so right there you're saving about 3kg, and improving your starting performance.

Food for thought, and no affiliation here but I gifted my Father one of those batteries for his BMW HP2 Sport... which are notoriously hard on batteries. This thing flicks it over and ignites it in half a second; wha-BROW! The factory standard one never did that, even from new.

More minor savings could be had by going to smaller mirrors and using alloy hand levers.

Cheers - boingk

 

[Rover]

that be more like a dead weight saving. Middle of bike but a good set of 33MM smoothbores are good for 8-10Hp. Been told ten pounds of weight on a bike is equal to 1HP

Trying to wrap my head around this.If one rider weighs 150 and another 250 is there 10 Hp to be had?

 

[GregT]

Fiberglass seat base is a mere fraction of the weight of the steel original..

Any aftermarket carb set will be lighter than OE as the OE carbs are on a heavy cast backplate.

 

[John Kat]

Seeing as you've saved 7.5kg of weight from your unsprung weight alone(!), I think you'd already find her drastically different to ride. Unsprung mass has a far greater effect than centralised (sprung) mass. Good job!

I'd look at removing the airbox and replacing with a good set of pods. This saves a large amount of weight (3~4kg) on these bikes and will also increase power. Another step would be to use a LiFePo4 ('Lithium') type battery to save even more weight - a quick reference to here:

http://www.ssbpowersport.com.au/tabid/241/mode/showbatterytypes/btsid/32/default.aspx

sees you needing an LH14L-BS, throwing out over 400CCA at 12v and weighing a scant 1.1kg. A Yuasa 14Ah lead-acid battery weighs around 4kg with acid so right there you're saving about 3kg, and improving your starting performance.

Food for thought, and no affiliation here but I gifted my Father one of those batteries for his BMW HP2 Sport... which are notoriously hard on batteries. This thing flicks it over and ignites it in half a second; wha-BROW! The factory standard one never did that, even from new.

More minor savings could be had by going to smaller mirrors and using alloy hand levers.

Cheers - boingk

I just came back from a 100 km test ride with the bike
To the " old vs modern" fans (see my thread http://www.thegsresources.com/_forum/showthread.php?t=214509 ) rest assured the bike remains in the (not so) old category as it reels and rolls on rough roads but at no moment did I get the dreaded weave dance
The front fork (with the much lighter wheel) is definitely superior specially with the gold valve and the .95Kg/mm springs.
The turn-in is also much improved with the 18"wheel and probably a little less rake with the shorter fork legs.
Thanks for the tip on the battery!
Oddly enough, I was looking up the adds for an HP 2 a couple of days ago...
Must be a nice bike to ride

 

[John Kat]

Fiberglass seat base is a mere fraction of the weight of the steel original..

I have one on my GS 1000 XP but I haven't weighed it yet...

Where could I find another one?

 

[hampshirehog]

Somebody makes them over here but I'm not sure who. Worth trying:

http://www.motorcycleseats.co.uk/suzuki-seats.php

or this guy on Ebay:

http://www.ebay.co.uk/itm/Motorcycl...pt=UK_Motorcycle_Parts_13&hash=item2a32c69e43

They might be connected as there's only 17 miles between the 2.

Busters used to sell them up until 2 or 3 years ago - they might tell you who there supplier was. www.busters-accessories.co.uk

 

[sharpy]

Trying to wrap my head around this.If one rider weighs 150 and another 250 is there 10 Hp to be had?

yep, that what i was told 100Lb (45kg) is a hell of lot of weight. Next time you go shopping pick up a 40lb (18.1kg) bag of dog food and think of 2.5 times that strapped on the bike.

 

[ozman]

these seats look great on the s model

http://www.ebay.com/bhp/giuliari-seat

fibreglass base they pop up on ebay uk from time to time

 

[salty_monk]

here is ure swingarm answer...

Depends on the swingarm... the earlier GS1000 swingarms have a bigger diameter arm & the saving is closer to 7lb from memory (when I weighed mine).

The later 80+ swingarms are different & smaller dia.

Again all this is from memory so don't shoot me if I'm wrong...

 

[boingk]

Thanks for the tip on the battery!
Oddly enough, I was looking up the adds for an HP 2 a couple of days ago...
Must be a nice bike to ride

No worries, again no affiliation I was just really impressed about how it transformed the HP2 - from a cranky, sullenly starting bugger into a simple one-hit wonder.

The HP2 is an insane bike, torque curve that's flat from 2500rpm upward and power to match - think its rated at about 135rwhp. Weight is under 420lb fuelled. The whole thing is an orgy of carbon, steel trellis and focussed speed. Too bad I haven't had a ride yet

On weight savings versus power, it doesn't really work that way. I think of it more in terms of your handling and acceleration. Losing weight means you've got a better power to weight ratio... so better quarter mile times etc. You'll still hit the same top speed.

Cheers - boingk

 

[John Kat]

I made another weight saving on my GS 1000 S today
The original sprocket cover was replaced by a copy of the original XR 69 sprocket cover.
Many thanks to Ozman for shipping this all the way from Australia!
Next I'll have to find a suitable alternator to fit on the sprocket cover to mimick the period endurance racers

 

[Wraith]

I did this with my sprocket cover to save waight



If you want wight saving have a look at this
271327549798 on eb*y

 

[John Kat]

I bought myself a kitchen type scale graduated to 5 kg to measure the smaller weight savings
Rear sprocket: 530 Supersprox 48 T 1004 grammes vs 630 std 42 T 1834 gr
Engine sprocket cover: XR69 Alu copy 845 gr vs OEM 1241 gr
Instrument panel: GSXR 11 G/H 1129 gr vs GS 1000 1599 gr.
So on these three items alone a saving of 4674-2978= 1696 grammes
To be added to the 11,1 kg already accounted for or a current total of 12,7 kg.
I believe the weight saving on the exhaust has been underestimated and I still need to take into account the rear caliper, the front mudguard, the drive chain ( from 630 to 530), the rear swingarm and some smaller items I'm thinking about.

 

[Frank Z.]

Nice work, Mr. Kat. One diet that makes sense to me.

 

[Guest]

Weighty

Weighty

Hiya John
You got some good posts going there and more should pay attention.
While I would suggest some of those Carbon Fiber wheels to get some Kilos out of it, they are a little pricey to justify. But a fiberglass seat base, a single shock GSXR arm and single shock to get rid of the twins and a non-inverts front end and 17" wheels from an early 2000's GSXR to get more weight out of it. And the electronic gauges will save even more weight. Just add a trigger on the countershaft cover. Someplace next to the alt? Or perhaps, on the rear wheel with a special trigger wheel? Just a thought. Oh, and change to a more compact ignition as well. Grams here and there and everywhere all add up. Oh, how about making an aluminum rear sub-frame? Aluminum handle bars. Aluminum brake master cylinders as well. Plastic headlight and bucket?
How much do you think it weighs now?
Light is right!
Laters
Greg

 

[John Kat]

Hiya John
You got some good posts going there and more should pay attention.
While I would suggest some of those Carbon Fiber wheels to get some Kilos out of it, they are a little pricey to justify. But a fiberglass seat base, a single shock GSXR arm and single shock to get rid of the twins and a non-inverts front end and 17" wheels from an early 2000's GSXR to get more weight out of it. And the electronic gauges will save even more weight. Just add a trigger on the countershaft cover. Someplace next to the alt? Or perhaps, on the rear wheel with a special trigger wheel? Just a thought. Oh, and change to a more compact ignition as well. Grams here and there and everywhere all add up. Oh, how about making an aluminum rear sub-frame? Aluminum handle bars. Aluminum brake master cylinders as well. Plastic headlight and bucket?
How much do you think it weighs now?
Light is right!
Laters
Greg

Hi Greg,

Yes, there is no limit ( with money) to how far you can go to reduce weight.
It would be interesting to get the weights of the modern GSXR wheels?
I was led to believe that the 6 spoke GSXR 11 G/H wheels were the lightest ever made at least for the front?
Going carbon would be ...unreal at least for my pocket
Also remember that I'm modifying my "standard" GS 1000 ST as I have another one fitted with an Ohlins single shock, a fiberglass based seat and many other mods to get the most out of the package without any concern about keeping it "stock".
The result is two very different bikes for different purposes but you are right: weight is the ennemy
When the bike is done I'll try to find a scale to weight it!