Tuning your Kat – the basics

A standard Kat is nice as standard, and a valuable classic as is, but it’s very hard to resist the temptation of modifying it. You can hardly find one that hasn’t been tweaked to the max. In my point of view for a Kat to remain a Kat you have to retain the standard fairing, tank and frame. So here are some of the options…

Engine tuning

Well, what can we say about tuning GSX1100 engines other than the sky is the limit? Thanks to the immense popularity with drag-racers you can build an entire engine completely from aftermarket stuff.
It has to be said that the drag bike guys have been moving more and more towards the GSX-R/Bandit engines purely because the supply of fresh engines is becoming more scarce. The most popular tuning method for a GSX1100 engine is the big-bore kit in combination with a top-end overhaul including a headflow, hotter cams and maybe bigger valves. A good excuse for taking such action is when the engine starts burning oil after churning away lots of miles. Anyway, you could go on and on about the options and still only cover 50% so I won’t go with that.
Many people are opting to fit an 1127 (GSX-R) engine, which is a dead shame for people who love the old GSX1100 engine, but a very good alternative if you’re after a low-mileage and reliable power plant.

Chassis tuning

Front end

From Suzuki’s point of view a headstock is just two bearings holding a steering stem (won’t argue with that 😉 and so they felt little need to change it’s design and dimensions during the last few decades.

That means that about any Suzuki front-end will fit the Katana… you’re free to interchange the front-ends of Bandits, GSX-R’s, Katana’s and GSX’s from about every capacity class, and even a CBR600 front end mixes in. Just remember to swap the whole front end incl. yokes and it’ll be a very straightforward swap. Keep in mind you’ll possibly lose some ground clearance after fitting smaller 17″ wheels and somewhat shorter forks.

Rear end

The space between the frame rails is 240mm. You need 30mm for the (25mm) chain to run free between the frame and the tire and 30mm on the other side to keep the wheel centered. So your maximum tire width = 240 – 30 – 30 = 180mm
To get there you need to move the sprocket outwards using an offset sprocket and maybe a spacer or two.
People who want to go wider than 180, like dragracers, need to widen the frame at the swingarm pivot and fit an outrigger bearing to the driveshaft (to keep the bending forces in control).
The hub will probably also need modification to bring the chainwheel closer to the inside.

The first 7/11

The original 7/11 was built by Bradley O’ Connor and was featured in Performance Bikes Magazine Sept. ’92. He put a GSX1100F engine in a GSX-R750 chassis to create a bike that gave him the same surge of adrenaline as he got from riding a Kawasaki ZZR-1100 without spending a lot of money.bradley

Although built from standard parts and any further tuning it was measured to outperform the ZZR on every aspect. His bike became a inspiration to many and nowadays there must be hundreds of 7/11’s on the streets. Bradley later added nitrous and put the engine in a Harris Magnum 4 frame.

The combination of the monster torque of a GSX-R1100 and the light weight and short(er) wheelbase of a 750 chassis results in a bike which; “Has enough torque to pull a Brontosaurus out of quicksand” and “Leaps out of your hands coming out of corners without even being asked

brad711And that is exactly what we 7/11 owners want, a affordable bike witch will give you that same feeling of sheer power that you got when you got on a 1100 for the first time, even when you own it for years now, something you just won’t get used to.