Camshaft tuning

If  you've got a no-bar bike there's no point in aiming for maximum horsepower, instead - try and get a nice and fat torque curve. The first 330' at the track is where you cut low ET's at. Horsepower gives you a higher MPH in the speed trap but rarely lower ET using the same motor internals. Torque, that's what makes your bike move. You'll run faster on the 1/4 mile with a 180 hp 110 ft-motor lbs than with a 200 hp 100 ft-lbs motor IF you can use the torque, otherwise it doesn't matter what kind of motor setup you use.

Camshafts, valves and rockers

My own reflections: Don't buy used camshafts for your race motor unless you're really on a budget. Buy a new set of cams instead. Race cams is very often not hardened correctly and will start to pit after a couple of thousand miles. Check the rockers VERY frequently, the chromed surface will eventually flake off - it's just a matter of time. The soft metal under the chrome will give away which makes the chrome layer flake off. Don't torque the rocker screw's nut too much, you'll strip it's threads. You only need to buy new nuts, the screw's are hardened and will survive the abuse. The Bandit (or GSXR) will only accept .380" cams due too retainer to valve seal clearance. The stock B12 pistons will not accept .380 cams unless you go higher (larger number) than 106 degrees on both intake and exhaust.

There are four major manufacturer of camshafts, Yoshimura, Web Cam, Cam Motion and Megacycle. All four of them makes a .380" lift cam for the GSX-R1100 which gives a valve/piston clearance of .050 - 0.060". Adds aprox 10hp. Slotting the cam sprockets is a must for maximum performance. Cope Racing has Falicon slotted cam sprockets for the Bandit. Properly dialed in slotted cam sprockets can gain +4hp over stock cam timing.

Performance Bikes used 112/106 (intake/exhaust) timing which gave top end performance.

The -98 IDBA Street ET champ Brad Stagg has got Yosh Stage 1 @ 102/105, Yosh SSR2 pipe and 36mm Mikuni RS.

The original (stock) B12 intake cam has 0.331" lift

-90 GSX-R1100L intake cam can be installed without modifications, gives aprox 5hp extra.


A word of wisdom from Brad regarding Yosh camshafts:

Megacycle makes a very similar intake cam but recommends stronger valve springs and Yosh doesn't. The Yosh exhaust cam has less lift than the megacycle making piston clearence easier and most top R motor builders say its way over exhausted anyway.


Another word of wisdom from Brad:

Have seen both mega cycle and V&H regrinds go south as well as welded up rockers, the Yosh cams do look nice actually they are hard to tell from stock in apearence. if you want good cams try the Suzuki cams unless your wanting to get real radical. The '90 gsxr 1100 and '88 gsxr 750 cams are much larger than the stock B12 cams and yes they are different from year to year even though the C/L and duration specs are the same the profiles are different. by the way the numbers on the cams 27A for example mean nothing except the casting .


A word of wisdom from regarding megacycles camshafts:

Beware the megacycle: They will come from them ostensibly clean and ready to install, and be saturated in grinding dust and chips. Their surface hardening does not always work. Their springs are so hard that they wear followers terribly. They do make some good cams, but be careful.


E-mail reply from Cope Racing (Web-site) regarding camshafts to the Bandit:

Anders, the .380 lift cam part # 44107 for the early style GSXR heads 86-90 is made by Cam Motion. These are the only cams I would recommend and they fit the Bandit head. We can get you a set of slotted cam sprockets from Falicon Engineering, the price is $38.00. I have not had experience with the lock-up clutch for this model.You will probably have to convert your hydraulic clutch to manual clutch lever, get internal spring type clutch components from an early GSXR 1100 1986 - 88. Then you might be able to use early GSXR lock-up clutch. I suggest you contact M.R.E at 1-800-237-7723.





GSF1200 stock cam specifications (thanks to RFRR900):
Intake at 0.001" lift:: open @ 42 deg BTDC, close @ 65 deg ABDC, duration 287 degrees
Intake at 0.040" lift: open @ 5 deg BTDC, close @ 32 deg ABDC, duration 217 degrees
Intake lobe center line: 104 degrees
Exhaust at 0.001" lift: open @ 52 deg BBDC, close @ 27 ATDC, duration 259 degrees
Exhaust at 0.040" lift: open @ 32 deg BBDC, close @ 6 deg ATDC, duration 218 degrees
Exhaust lobe center line: 103 degrees

GSXR1100 86-90 stock cam specifications:
Intake at 0.001" lift:: open @ 42 deg BTDC, close @ 70 deg ABDC, duration 292 degrees
Intake lobe center line: 104 degrees
Exhaust at 0.001" lift: open @ 65 deg BBDC, close @ 39 ATDC, duration 284 degrees
Exhaust lobe center line: 103 degrees

When installing GSXR camshafts on a Bandit you can/should install slotted cam sprockets,
can be bought from Falicon Crankshaft Components, $45 for a set of sprockets.