Will These cams fit???

I have an 81csr1000 (as my username openly brags) and I am in the process of rebuilding the engine. I have come across the opportunity to pick up a set of cams on a killer deal from a buddy that has been big into the kawi game forever. I have a kerker 4-1 header with pro pipe, and am plenty capable of the carb tuning.

The cams are both .410 lift cams. One is engle and one is an andrews. I still have stock pistons. I want to know if anyone has experience with these cams or something similar and can tell me if these are going to fit, or if a valve is going to have a very "face to face" meeting with the top of a piston. I have read on the APE .410 cam that you cannot use stock pistons but that has almost 20 degrees of added duration over the cams i'm getting.

If those won't fit, would anyone have experience with a web-cams 218 grind? Can I use THAT cam with stock pistons?

I know i'll have to clearance the head and valve cover and run different springs/tappets, that's no problem. I just don't want to buy a $600 set of pistons just so I can fit some cams. I'll probably also get adjustable cam sprockets to get everything just where it needs to be.

Thanks!

Don't really know If they will work without knowing their profile. It has been my experience that putting in performance camshafts on a stock motor really does not give you much of anything without other mods to compliment the cams such as high compression pistons, porting, bigger carbs, ect.

I plan to clean up the casting flash on the ports, but that's about it for head work. I have 34mm carbs, and a 4-1 header. Should move plenty of Air.

They are a tiny bit different initake/exhaust, but I know the specs on one. they are 266/266 @.030. .410/.410. At 50, they should only be like 242/242, much smaller than the APE grind.

You will need to clearance the bucket bores for those cams.
Degree them at 110 degrees to start if you don't have the specific timing figures.
You won't have clearance issues with the std pistons.

So since I'm seeing that they will fit with some clearancing, does anybody have any jetting recommendations to get me in the ballpark?

Id do more homework, I believe the K410's are the same grind as the .410 lift Andrews, if so, stock pistons won't cut it. I'd call APE and speak with Jay if at all possible and clarify what I'm thinking, better safe than sorry.

Les Holt

It has been my experience that putting in performance camshafts on a stock motor really does not give you much of anything without other mods to compliment the cams such as high compression pistons, porting, bigger carbs, ect.

I think about what the limiting factors are and how it all works together; without a bigger bore and worked head to use it , more valve time area might not achieve anything.

I'm thinking 262 degrees at .030 " is a pretty hot cam, .410" lift sounds pretty high. You will lose bottom end grunt for certain, whether you can pick much rpm power up without further tuning is questionable.

If in doubt about piston clearance I 'd assemble the motor and dial in, checking your clearances using clay on the valve cut outs . Graph your valve interference curves from a cam chart if you have - a lot of skilled work and things can go bang if you get it wrong. Also check if you need heavy duty springs.

A graph of valve lift, then I set it up and measure clearance between them before and after TDC.






My GPz11 had CV34, kerker and late factory cams, I think about 288 or 300 degrees, (at zero lift) it was arm wrenching powerful but really lacking in bottom end grunt, for the crazy rpm power it had.

The engine design changed in the 1983 model to use underbucket shims similar to the z650 and the camshaft duration was increased from 288 degrees to 300 degrees, and the valve lift increased from 8.7mm to 9.5mm. To flow more air, the head was revised extensively from the earlier model, featuring new ports, a 'bathtub' combustion chamber borrowed from their own S2 racer, and a 1mm larger intake valve recessed into the head slightly for valve clearance. The power output was now claimed to be 120 bhp (89 kW) at 8,750 rpm.[2] CYCLE magazine recorded 104 rear-wheel horsepower on their dynamometer, and Kawasaki was hoping to have a solid 10-second quarter-mile machine, but the increase in power at the upper RPM ranges lowered the torque at lower RPM's, so taking advantage of that power anywhere but on a racetrack was difficult

en.wikipedia.org/wiki/Kawasaki_GPZ1100