Advancing factory cams?

So Let me see if I'm grasping all this.

KZ1000 intake cams: open 30 degrees btdc, closes 70 degrees abdc, total duration of 280 degrees.

So

280 (duration) / 2 (to find the center) =140 degrees

140 (center of cam lobe) - 30 (degrees btdc has to be subtracted to get where the center is compared to the crank??) = 110 degrees atdc (lobe center??)

A good mod for stock bikes both suzuki gs and kz kaws, is to bring lobecenters down to 104 to 105 intake and exhaust.

So thats a 5 degree difference and it makes that big of a difference?? Can I do this to my 650?? This is very interesting.

Never mind. I just crunched the numbers for the 650. It's already at 105. think I could move it a few more degrees out or am I wasting my time??

put a degree wheel on there and see where they actually are,anytime youve got half a million of something mass produced youve got room for error from the word go not to mention when you throw 30 years and 30,000 miles worth of wear into the picture.

coopstream wrote:

You dont happen to have anymore details on those crazy lobe centers, do you? Or maybe a contact?

I don't know the centers he spoke about but If I had to guess, I think they would be more intake advance and more retard on the exhaust. The valve to piston clearance is minimum when at 105 intake so anything from there may require deepening the valve releif pockets on the piston so the intake doesnt hit it. Probably the same on the exhaust. It's just a guess but I'm going to assume Dale was trying to get the torque to increase, which helps off the line and through the quarter mile. If you overrev with 105 centers it's likely you'll bend a valve, since they are close to the piston. Valves actually float alot earlier in the rpm then realized, they just have enough clearance not to hit the piston. New valve springs can be the best tune up for an engine turning some rpms. From the time you start the motor to making a few runs the springs lose their stiffness. To make more power your going to have to do it exactely the way you would with the chev motor, it's the only way your going to see an increase in usable power from the motor. As much compression as you can get and the biggest bang. If the engine can pull in more fuel at higher rpms, it doesn't matter how much if it isn't under enough pressure to make a more powerful downward stroke. Dale states that with 104 to 105 lc the engine will have a good broad powerband.

I really appreciate your help with this. I guess I'll get some adjustable sprokets, maybe get some tigher springs, get some clay out, and roll em back to 105. Its gonna be a while before the bike is finished, but I'll post the results. I really appreciate it.

I agree, get a degree wheel on your 650. If at the very least, make sure the cams are at the factory spec. If you have ever heard the exprssion, "You must have gotten one of those Friday Engines", its because someone took their time specing the engine at the factory. In my personal experience lobe center and lobe seperation are the magic Voo Doo in making power. Webcamshafts, has an interesting piece on degreeing cams. The link is on their home page.

I think APE do a cam sprocket that you can use to put GPZ1100
B2, A3-A4 cams into KZ's these are a really good cam and should be reasonably cheap and easy to find, Try them at 106-106 stock for these cams is 105 - 108

Not trying to insult here but you'll need more than just a degree wheel for CAM Degreeing...

You might want to read through this to give yourself a better idea of what your facing pre buying any parts....

kzrider.com/index.php?option=com_docman&...d&gid=451&Itemid=108

OMR

well yeah,its part of the kit! :laugh:

dailing in a cam just moves the power range to where you want it.you con gain compressin by changing over lap, if both valves are closed when the piston is at the bottem you get more squeeeze