1983 Katana 1100 Race Build

[salty_monk]

Posplayr runs a 170 on a 4.5" rim. Avon's guide says that's allowable. You can run a 120 on a 3.5" but it might turn better with a 110....

[steve murdoch]

Good on ya, AMX.
Just curious as to whether an '82 1100E swingarm is different than an '83 Kat swingarm.

[TheCafeKid]

What are the rules on shock length?

A thought, if you get stuck with 18" wheels as the only viable choice given the time period constraints, would be a slight longer shock, to quicken the steering. Not much, and maybe even slip the forks up in the trees a 1/4" if youre allowed, but i wouldnt go much farther than that as you'll want as much fork travel without interference as possible.

Remember, springs and damping just hard/soft enough to do the job. Anything more or less, front OR back, and she'll handle like an ill tempered mule. (Go where SHE wants to go coming in or out of the corners..)

Im gonna guess that there are some limitations on engine performance/modifications. If so, you'll want to concentrate your efforts on suspension set up and getting rid of as much flex as you can. And of course being a smooth, efficient rider But if theres a HP output max, or whatever, that goes out the window, as there wont be much from the era that can compete with a big GS1100 mill, and you'll want that bike to be razor sharp so you can get on that throttle ASAP and use that low end grunt to beat the lighter bikes out of the apex...

Ive never raced, mind you, but damn Id like to try it....

[D Nuts]

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 (come to think of it, I'm wondering whether 82 GS 1100 front forks would swap over, offer me the opportunity to install the 17 inch 3 1/2 inch wheel and the superbike bar comes OEM me thinks). Not sure about mod options for internals though? 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.

What are the rules on shock length?

A thought, if you get stuck with 18" wheels as the only viable choice given the time period constraints, would be a slight longer shock, to quicken the steering. Not much, and maybe even slip the forks up in the trees a 1/4" if youre allowed, but i wouldnt go much farther than that as you'll want as much fork travel without interference as possible.

Remember, springs and damping just hard/soft enough to do the job. Anything more or less, front OR back, and she'll handle like an ill tempered mule. (Go where SHE wants to go coming in or out of the corners..)

Im gonna guess that there are some limitations on engine performance/modifications. If so, you'll want to concentrate your efforts on suspension set up and getting rid of as much flex as you can. And of course being a smooth, efficient rider But if theres a HP output max, or whatever, that goes out the window, as there wont be much from the era that can compete with a big GS1100 mill, and you'll want that bike to be razor sharp so you can get on that throttle ASAP and use that low end grunt to beat the lighter bikes out of the apex...

Ive never raced, mind you, but damn Id like to try it....

[D Nuts]

thats what was suggested to me so that I could fit the 4 1/2 inch rear rim. i'm gonna find out

Good on ya, AMX.
Just curious as to whether an '82 1100E swingarm is different than an '83 Kat swingarm.

[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.