1983 Katana 1100 Race Build

[TheCafeKid]

Handling is defintely my initial priority.

The rules allow for 17's and rims up to 3 1/2 front and 4 1/2 rear. Im looking for CBR F2 rims that I learned from this thread will fit on the GS1100 swingarm I'm going to pick up this week, but I'm not sure about the front OEM forks (I'm hoping smaller spacers, but I'm not sure about that and the front caliper (soon to be Brembo F08's). If I can fit the front CBR rim on the OEM fork, I'll likely keep the OEM fork, but I do what to install a superbike bar. Im also looking for CB1000F rotors as suggested in the thread as well (not easy so far to find). Having said, Im looking for alternatives to Ohlins shocks, but will get them if there isnt anything close (as well, I havent found something close enough that is available). Im not going to focus on engine for now. Maybe carbs though as mine have to be removed and cleaned up, but defintely individual K & N filters for better breathing and for far lesser reasons (but added bonus), access to the battery and weight reduction.

Welly boyo,

If and when ya get to that point, I have a set of KYB shocks off a ZRX1200R (piggyback, adjustable rebound and compression damping, etc etc) that i would sell comparitively cheap (to ohlins or the like)

They're one inch over stock length, and eye to eye, so you'd have to change up the mount on the swinger (which if you're going to have it braced, your welding man could fab some up, or KATMAN makes em, and he could weld em on for ya)

But, they're rebuildable, re-valveable thru RaceTech, and all that..and a damn sight better than anything stock of your bikes era, and a hell of alot cheaper than Ohlins.

BTW, your Kat has an alu boxed swinger, same as the 1100E did...should be the same arm i think?? Got a pic? That should take the wheels without problem

What bikes were running 17" wheels in 82???

 

[D Nuts]

I read somewhere that the stock 83 Kat 1100 swing can take a 4 1/2 inch reach wheel, but the brake mount needed to be moved. I certainly dont wanna change the swing arm to an 82 GS1100 if the OEM can take a 4 1/2 inch rim unless thers some other advantage. I'm gonna keep taking a look around for aftermarket shock options. Im gonna investigate the swing arm difference more.

The VRRA rules allow for 17 inch which is great. Even slicks are permitted in the next period up.

Welly boyo,

If and when ya get to that point, I have a set of KYB shocks off a ZRX1200R (piggyback, adjustable rebound and compression damping, etc etc) that i would sell comparitively cheap (to ohlins or the like)

They're one inch over stock length, and eye to eye, so you'd have to change up the mount on the swinger (which if you're going to have it braced, your welding man could fab some up, or KATMAN makes em, and he could weld em on for ya)

But, they're rebuildable, re-valveable thru RaceTech, and all that..and a damn sight better than anything stock of your bikes era, and a hell of alot cheaper than Ohlins.

BTW, your Kat has an alu boxed swinger, same as the 1100E did...should be the same arm i think?? Got a pic? That should take the wheels without problem

What bikes were running 17" wheels in 82???

 

[TheCafeKid]

Well I'm not the Kat guy, but I'm pretty certain they're the same arm. You may also look into a later model GS750/1150 arm. They're monoshock arms but they may be a bit shorter in length to help shorten up the wheelbase.
I would suggest not making the wheelbase too much shorter, as one of the benefits the Zooks of old had over the Kwacks was their high speed stability because of their slightly longer base. Do the rules allow for a steering damper?
Watch out cause a short wheel base will make turn in sharp, but can make for some wicked midcorner/highspeed headshake. That can turn into a tankslapper pretty quick. Scary.

Whatever arm you go with, to use an aftermarket brake set you'll probably have to go with an underslung torque arm for the caliper. Which means you'll have to have the arm modified anyway. No stock GS had an underslung rear brake. And keep in mind, while a wider rim/tire set up will work in the stock arm, your stock torque arm wont. It will rub the tire even with a 150. So that will have to be fabricated as well. Easy enough. I learned that when I put an 3.5" 1150 wheel on my GS1100ES.

A calfab arm like El G shows in his pic would be a good snag as it's already got trapezed bracing, but I'd suggest you make friends with someone who cal weld/fabricate with Aluminium. You might also send Blowerbike here on the board a PM. Last I knew, he had some GS applicable custom made cast iron brake rotors that might work with whatever brake set up you go with. Maybe not. But worth an ask at any rate.

I envy you brudder. This sounds like it will at very least be a fun project. And if ya get to actually put it on a grid, that's a win right there.

 

[El Giablo]

The swing arms ARE the same. El G.

 

[D Nuts]

Thanks, that saved my a 90 minute drive each way!

The swing arms ARE the same. El G.

 

[El Giablo]

I also have a 4.5 rear wheel for you. El G.

 

[D Nuts]

A damper and fork brace is permitted. I cant go later model with the arm though. Ive seen many mod to move the caliper so Im defintely gonna have to find someone who can do so. It seems the best calipers staying within the period is the Brembo F08 (for the $). Thnx

Well I'm not the Kat guy, but I'm pretty certain they're the same arm. You may also look into a later model GS750/1150 arm. They're monoshock arms but they may be a bit shorter in length to help shorten up the wheelbase.
I would suggest not making the wheelbase too much shorter, as one of the benefits the Zooks of old had over the Kwacks was their high speed stability because of their slightly longer base. Do the rules allow for a steering damper?
Watch out cause a short wheel base will make turn in sharp, but can make for some wicked midcorner/highspeed headshake. That can turn into a tankslapper pretty quick. Scary.

Whatever arm you go with, to use an aftermarket brake set you'll probably have to go with an underslung torque arm for the caliper. Which means you'll have to have the arm modified anyway. No stock GS had an underslung rear brake. And keep in mind, while a wider rim/tire set up will work in the stock arm, your stock torque arm wont. It will rub the tire even with a 150. So that will have to be fabricated as well. Easy enough. I learned that when I put an 3.5" 1150 wheel on my GS1100ES.

A calfab arm like El G shows in his pic would be a good snag as it's already got trapezed bracing, but I'd suggest you make friends with someone who cal weld/fabricate with Aluminium. You might also send Blowerbike here on the board a PM. Last I knew, he had some GS applicable custom made cast iron brake rotors that might work with whatever brake set up you go with. Maybe not. But worth an ask at any rate.

I envy you brudder. This sounds like it will at very least be a fun project. And if ya get to actually put it on a grid, that's a win right there.

 

[TheCafeKid]

I saw that thread Greg was talking about with the GS1K. He ran an underslung brake but he ran the arm and mounted it where the centerstand brackets are. It would work, and I'm guessig it passed tech cause he raced it. But I'd spend the dough and get that arm set up nice.

So what kind of purses are these classes usually going after? How many races etc? Sorry to go off subject but this stuff interests me. Living vicariously.

 

[D Nuts]

Purses are only for the girls up here in Vintage. Just a shinny trophy and I doubt I'll be getting one, but my smile will be just as shinny when it gets done and I'm on the grid.

I saw that thread Greg was talking about with the GS1K. He ran an underslung brake but he ran the arm and mounted it where the centerstand brackets are. It would work, and I'm guessig it passed tech cause he raced it. But I'd spend the dough and get that arm set up nice.

So what kind of purses are these classes usually going after? How many races etc? Sorry to go off subject but this stuff interests me. Living vicariously.

 

[TheCafeKid]

Btw when you get into cutting weight, lemme know. I've a machinist buddy/oldschool race builder buddy who can make ya some sweet chit on the cheap to cut weight. Drilled axles, billet 7075 spacers to replace steel, even one off billet or magnesium braces (but Mag costs bucks...worth it but bucks)
Little stuff would be affordable and help out a little at a time.
The guy knows is stuff. Used to build/race in south Africa. Has a Bimota KB3 (prolly the only one in the states), a real rickman Honda, etc etc. His KB3 has carillo rods, cosworth pistons, yosh cams...all built himself. It SCREAMS.

 

[D Nuts]

I'll be cutting weight in the spring no doubt. I wanna get down to 160.

Btw when you get into cutting weight, lemme know. I've a machinist buddy/oldschool race builder buddy who can make ya some sweet chit on the cheap to cut weight. Drilled axles, billet 7075 spacers to replace steel, even one off billet or magnesium braces (but Mag costs bucks...worth it but bucks)
Little stuff would be affordable and help out a little at a time.
The guy knows is stuff. Used to build/race in south Africa. Has a Bimota KB3 (prolly the only one in the states), a real rickman Honda, etc etc. His KB3 has carillo rods, cosworth pistons, yosh cams...all built himself. It SCREAMS.

 

[TheCafeKid]

Purses are only for the girls up here in Vintage. Just a shinny trophy and I doubt I'll be getting one, but my smile will be just as shinny when it gets done and I'm on the grid.

Ya got the right attitude already. I just figured there'd be at least a lil money in it to keep the grids full/bikes on em. Etc. Guess not . It's a sport of passion. Lol.

 

[D Nuts]

anyone know of anyone who has converted with the stock upper to superbike bars and where they found the longer lines? thnx much

 

[Buffalo Bill]

Just another GS1000 build post to read

Just another GS1000 build post to read

I found this post about a GS1000 race bike build, might be useful for you:
http://oldskoolsuzuki.info/

[FONT=Arial, Helvetica, sans-serif]search for: Craig's GS1000 racebike[/FONT]

 

[John Kat]

anyone know of anyone who has converted with the stock upper to superbike bars and where they found the longer lines? thnx much

In Europe ABM has many superbike upgrade kits.
http://www.ab-m.de/en/products

 

[gs58]

I'm running a bike in NZ built to similar rules to yours. I'm running GSXR wheels (3.5 front, 4.5 rear) with custom cast iron rotors (originally used Yam XS1100 rotors to get 300mm diameter), Brembo 08's, GS 1000 forks with emulators, GS1100 swing arm, 520 chain and sprockets, GSX1100 triple clamps to get better off set and sufficient clearance for calipers to mount, Ohlins way over stock length to get better front geometry (originally used Koni), and a bunch of other stuff. I am using the stock GSXR rear disc but have spaced it from the wheel for clearance and fabricated another mount and torque arm.

This is a reasonably common build in Australia and NZ, although many cut the steering head to sharpen the fork angle instead of raising the rear as I have. I am considering doing the frame mod to get more weight on the front wheel as it has washed out a couple of times. This was a common problem back in the day when they were be raced as stock bikes.

I am currently 120 and 180 Pirelli slicks which are working great. I have only braced the frame at the steering head but need to do more in the swing arm area.

Best of luck and enjoy the build.

 

[gs58]

GSX1100 triple clamps to get better off set and sufficient clearance for calipers to mount

My mistake. that should read GSXR1100 triple clamps.

You will need to get adaptor plates for the calippers, spacers to adapt the 17" wheels, and a bunch of other stuff.

Find someone with a lathe and milling machine and the skills to use them, and make them your best friend.

 

[salty_monk]

If you are allowed later forks up to 41mm I would be looking at the GSXR1100 forks from about 1990... The triples are a bolt on (you need to weld/bolt some steering stops on possibly - not sure how they are on the Katana but I needed some on the 750).
The lower triple is also already setup for a steering damper.

You might also look at YZF forks, I think they are 41mm & RWU too... must be other bikes out there. Either get cartridge emulators or at least the newest tech you can get...

 

[TheCafeKid]

If you are allowed later forks up to 41mm I would be looking at the GSXR1100 forks from about 1990... The triples are a bolt on (you need to weld/bolt some steering stops on possibly - not sure how they are on the Katana but I needed some on the 750).
The lower triple is also already setup for a steering damper.

You might also look at YZF forks, I think they are 41mm & RWU too... must be other bikes out there. Either get cartridge emulators or at least the newest tech you can get...

Easiest route to 41mm forks would be GS1100GK forks and triple. That's bolt up and go. Not fancy like the gixxer with anti-dive but if he's allowed emulators he can make a damn nice set of forks. Besides I don't think I'd want antidive anyway if you trail brake to the apex. Let the fork compress to speed up the steering a little. GK forks would also fall just inside his model year limits if it applies to forks...