GS1000 streetfighter idea w/ picture

[80GS1000]

You could chop your frame a little. You already lost the passenger pegs, so you probably don't need all that seat (or do you have plans for riders?). Just a thought, and you obviously have the skills to do it.

My girlfriend lamented that when I chopped mine she wouldn't be able to ride on the back (I never rode with her, so I don't know how serious she was). I countered with the offer to help find a bike of her own, or to teach her to ride the 500. I'm not going to hold my breathe on that one.

I love the aggressive stance these mods have given your bike.

No plans to have passengers - my wife has her own '82 Honda CB750C that she loves to ride.

I've toyed with the idea of chopping the subframe, but am pretty sure it's going to stay intact.

This is because the early 80's AMA superbikes including the Yoshimura GS1000 had their complete seats and subframes unmodified. I also don't want the GS1000 to lose its identity - need to to still be able to tell by looks that it's a GS1000. With such little body work on the bike (really only seat, tank, and tailpiece), and with all the other mods that have been done, I don't think it'd look like a GS1000 anymore with a bobbed tail.

I will probably shave the foam and recover the seat though to clean up its lines (too tall!) and to provide more of a step, like the Yoshi GS1000 racebike: (original: http://oldskoolsuzuki.info/patrick/projects/knarf_gs1000/clink/, NICE replica: http://oldskoolsuzuki.info/yabb/Attachments/yoshi07.jpg)

In terms of design on this project, priorities are in order: safety, performance, then looks.

Tail up in the air is mostly functional - to get the rake/trail numbers right and to to weight the front tire. It's also a hallmark of the streetfighter style IMO. It does kinda look like an animal waiting to pounce, doesn't it?

 

[johnnay]

I set the pre-sag trail at a preliminary 3.75" with the floor jack and mocked up the GSXR monoshock. The rear shock and forks should sag about 1 to 1.5" with the weight of the bike and me on it, getting the total trail to about 3.9-4.0". To put this into perspective, a current spec GSXR 1000 has a trail of about 3.9".

Where are you getting your information about setting up the geometry? I'm moving a little slower than you on my bike, and haven't researched this yet. Any online resources you can recommend?[-o<

 

[80GS1000]

Where are you getting your information about setting up the geometry? I'm moving a little slower than you on my bike, and haven't researched this yet. Any online resources you can recommend?[-o<

Google's been a good resource.

In particular, these have been good articles:

http://www.sportrider.com/tech/146_0310_art/

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry

http://www.performanceoiltechnology.com/rake_and_trail.htm

 

[80GS1000]

10 inches of clearance in the front = a very high center of gravity = bad handling. It's going to take some experimentation to get the combination of factors right - ground clearance, rake/trail, center of gravity, chain clearance, swingarm geometry etc etc.

That and the fuel valve is in the back of the tank - with it tilted that far forward, you'd run out of gas sooner unless the tank were modded.

 

[80GS1000]

Great looking 1100! Specs?

 

[terbang]

the angle may be close enough that you can photoshop/cut and paste this seat on for size! :?

great project by the way, been watching a couple on the site with interest...

Like the bike there. What wheels have you got on there and also what are the front brakes..?

 

[johnnay]

Google's been a good resource.

In particular, these have been good articles:

http://www.sportrider.com/tech/146_0310_art/

http://en.wikipedia.org/wiki/Bicycle_and_motorcycle_geometry

http://www.performanceoiltechnology.com/rake_and_trail.htm

Beauty - thanks!

 

[solo suzuki]

Great looking 1100! Specs?

hummm, i thought everybody on this site would know about this bike by now (GSR BOTM march '03) etc. but, here goes...

i've owned this bike since the late 80s but it's been this way (chassis) since 1994 when we adapted the 5.5in rear wheel/brake/swingarm off of a gsx R 1100. the inverted front end didn't stay on there for very long because of ground clearance. this is my do everything bike: riding instructor/two up week end rides etc. and i couldn't clear speed bumps around here...well i did but had to change the 4 into 1 :-s so...i went back to the previous set up: gs1150 (EFE) front end, progressive springs etc. adapted the 17in. wheel,and the nissin 4p from the donor gsx R 1100, ferodo pads, 2nd gen. gsx F 290mm rotors, steel braded lines.

i could have raised the back end but wanted to keep the look, same reason i went for stereo shocks (works perf.) then there's the chain hitting the swingarm the higher you go etc. we did make a few mock ups before we grinded stuff off :-D

also, this was 1994, before internet for me and bike forums and ebay and...well i had never seen anybody else do this, plus around here everybody had a gsx R, so that made parts available when someone would crash an almost new bike with more cosmetic damage than the insurance were willing to pay for! \\/

 

[justin caise]

It's 20 degrees F out in the garage...
It's a balmy 73 here in the house.
Your bike is more fun to work on anyway.

Please don't go too crazy tho- this next one looks a bit much, I think.

 

[80GS1000]

Justin-

Thanks for taking the time to make those Photoshop prototypes. You have some skills. :-D

I think the first one is the winner. I'd put a bit more rounded "scoop" in the front like the Yoshimura GS1000 racebike, except I'd add a bit more padding to the Yoshi bike too where the seat meets the tank to, um, protect the family lineage. So, for my bike, leave the front the same, but have a curved "scoop" up to the flat part. Ideally, it'd flow as a single line smoothly from the curves of the tank to the tailpiece.

I agree with you on the second one.

Off to the garage to play around with steering geometry some more. Picked up a inclinometer and a digital caliper so we can get all the steering geometry dimensions and angles worked out on the conservative side. When it comes to steering geometry, I'd rather err on the side of stability vs. instability. Wobbly geometry could be repaid in pain, hospital bills, or worse. Safety, then performance, then looks.

Nice rake/trail calculator here - plug in your dimensions, out pops your rake/trail figures.

 

[80GS1000]

Steering geometry, take two

Steering geometry, take two

As was mentioned before, I picked up an inclinometer(angle meter) and used it plus an electronic caliper and tape measure to measure the steering geometry of the bike. Then the numbers were plugged into here and an ideal (for now, will have to remeasure about twenty times more before committing) steering geometry was arrived at after a bit of effort. Much more scientific and accurate than the previous effort.

It also made the bike look much more stock - rear end isn't as high up. The riding position is better, much like as it was when the bike was stock. And reaching the ground is pretty easy now too.

Measuring steering head angle:

A rare (wink) right side view of the bike:

The familiar view without side panel, notice the change in the stance:

And with side panel, which now looks like it works with the lines of the machine again:

 

[80GS1000]

Also stopped by a metal supply store to get some raw material for fabrication. There's a few high-stress-tolerant bolts hiding in the first rod from the front. The steel on that one is rated at 90,000 PSI yield, and 120,000 PSI tensile strength! Meaning, 90,000 pounds per square inch of sideways force would have to be applied to the bolt before it would bend, and you'd have to pull on it with 120k PSI for it to stretch. I think the frame would bend in half before that kind of force could be applied to the bike, so we're good for strength.

The bolts made from that rod will be used to mount the monoshock to the frame in the high stress areas.
The upper monoshock mounting plate will most likely also be made from this grade of steel, as will be the frame bracing that supports it.

The second, fatter rod will be turned into the bushing that matches up the GS pivot bolt with the inner diameter of the GSXR pivot point in the swingarm. The aluminum plate will become the electrical board for mounting under the seat.

 

[80GS1000]

New GSXR 1000 wheel, rotor, and sprocket arrived tonight. The rim is straight this time. \\/ And, as a bonus, it already had a Michelin Pilot Power 180 radial mounted, same brand and model as the tire up front. :-D

Mounted the swingarm up on the bike and took measurements for sprocket offset, It's going to be tight for chain clearance, so we're going with a 520 chain and sprockets.

Also firmed up measurements and specifications for the monoshock mounts.
I'll post pics of those when they come back from the machine shop.

Pic with new rim mocked up:

 

[beergood]

Congrats on getting good parts this time. Looks like things are coming along nicely.

If you're like me, you gotta be gettin really antsy to ride that thing.

 

[80GS1000]

Congrats on getting good parts this time. Looks like things are coming along nicely.

If you're like me, you gotta be gettin really antsy to ride that thing.

Oh for sure, killing me to just look at it in the garage. Makes ya want to work harder and put more hours in so it's ready for canyon carving by springtime. :-D

 

[Druro]

That is some fine work... wish mine was moving at the same clip, but a month long business trip will kinda ruin plans.

One question: Who are you ordering your sprocket from? The only one i know is PMR. IF you've got some links on those, please let me know.

Cheers.

 

[80GS1000]

That is some fine work... wish mine was moving at the same clip, but a month long business trip will kinda ruin plans.

One question: Who are you ordering your sprocket from? The only one i know is PMR. IF you've got some links on those, please let me know.

Cheers.

The spline on the countershaft sprocket is the same between the GSXR 1000 and the GS series. So any GSXR 1000 520/530 front sprocket will work with the right spacers. I'll be using a GSXR 1000 520 conversion kit that comes with a 520 RK U-ring chain (very thin but strong, they use these on the 160+ HP GSXR 1000s) and Vortex 520 front and rear sprockets. Also bought a handful of 1.5 and 6 mm spacers to get the offset right. The store I bought the chain and spockets from is http://www.sumofallparts.net/, got the spacers from http://z1enterprises.com/catalog.aspx?pid=GS1000ET-1980-MP1

JT Sprockets also has a great website with tech info on all their sprockets. Are you thinking of doing a chain conversion?

 

[Druro]

Well, i'm mounting up GSXR 1100 front end with matching rim at the back, and I'm going to need to space things out.

My only question is with the sproket/spacers you plan to use, are you not worried about the length of the output shaft as it relates the number of threads available once it's spaced out? Is there enough length to bolt on the sproket and the spacers?

might want to take a look at that.

I'm going to look at those sproket setups... might use something similar, but for the gsxr1100 rim.

Cheers

 

[80GS1000]

Well, i'm mounting up GSXR 1100 front end with matching rim at the back, and I'm going to need to space things out.

My only question is with the sproket/spacers you plan to use, are you not worried about the length of the output shaft as it relates the number of threads available once it's spaced out? Is there enough length to bolt on the sproket and the spacers?

might want to take a look at that.

I'm going to look at those sproket setups... might use something similar, but for the gsxr1100 rim.

Cheers

The amount of available threads is a concern for sure. We'll have to see if it works out once the parts arrive. Need about 2-3 exposed threads for security. If it doesn't work out, probably will wind up getting an offset front sprocket. Going for the least expensive solution initially - those offset front sprockets are $100+.

Another concern was making sure the steering stem was aligned with the center of the rear tire due to the difference in wheel spacers/rim diameter/swingarm width on the bike. Don't want a bike that pulls to once side or the other. Fortunately, it's dead center, so it'll track straight.

 

[2Fast4U]

The amount of available threads is a concern for sure. We'll have to see if it works out once the parts arrive. Need about 2-3 exposed threads for security. If it doesn't work out, probably will wind up getting an offset front sprocket. Going for the least expensive solution initially - those offset front sprockets are $100+.

Go here: http://www.afam.co.jp/E/index2.htm
my sprocket was $45 with shipping from Japan to So Cal.
The guys are really nice to deal with.