83-84 GPZ 1100 cams

cool, thx

Let us know what #s you get when you measure it.

Just measured the intake cam, it's .370" lift.

DFIGPZ wrote:

9am53 wrote:

Look at the bottom of this thread where Tim measured the GPz cams and says .375-.380. The .328 lift may have been the CSR or LTD cams, but I presume the .8mm increase your article states refers to a set of 81-82 GPz cams, or maybe a standard J cam

kzrider.com/index.php?option=com_kunena&...ew&catid=2&id=321585

i would say look at larrycavan post in the thread you posted #321743 he states GPZ approx 360 lift. buy them measure for yourself my 84 cams DO NOT measure 375 or 380 for whats its worth. in the end its all in what you want.

I measured a set for guy about 5 weeks ago. They were .365".

Good cam for small bore KZ900/1000 street motor.

Here's really the deal with those GPz11's.

Guys were hotrodding KZ1000 motors for quite a while with 1075 piston kits and 2x Andrews cams. A good ported KZ head with stock valves would flow mid 80's at 10".

Kawasaki basicaly delivered that setup in the 83 GPz11. A tad bigger bore, good head and DFI. They put out 104 rear wheel HP on Cycle Magazine's dyno test back then.

That's right in the neighborhood a typical 1075 with that combo puts out....

The more accurate way to measure it is to measure the base circle, then measure the overall height. Subtract the base from the overall. That's the advertised lift. You can subtract lash from that if you want.

DFIGPZ wrote:

otakar wrote:

DFIGPZ wrote:

FYI 1983 / 1984 GPZ 1100 cam specs:

INTAKE CAM .354 lift 238 deg

EXHAUST CAM .338 lift 239 deg

hope this helps.
Barry

The Megacycle diagrams tend to agree with you. I know that the standard "J" series intake cams are about .330 because I just measured them. These came from an CSR, that I just measured. Boy that makes me feel really radical, running .420 intakes and .410 exhausts. with 38.5mm intake valves, on my every day rider.

Nothing wrong with that i have 420 lift cams i have done for 900s with 1075 kit ported heads still running SOT retainers W/O issues.

SOT is the way to go on street motors Smart choice guy...

larrycavan wrote:

DFIGPZ wrote:

otakar wrote:

DFIGPZ wrote:

FYI 1983 / 1984 GPZ 1100 cam specs:

INTAKE CAM .354 lift 238 deg

EXHAUST CAM .338 lift 239 deg

hope this helps.
Barry

The Megacycle diagrams tend to agree with you. I know that the standard "J" series intake cams are about .330 because I just measured them. These came from an CSR, that I just measured. Boy that makes me feel really radical, running .420 intakes and .410 exhausts. with 38.5mm intake valves, on my every day rider.

Nothing wrong with that i have 420 lift cams i have done for 900s with 1075 kit ported heads still running SOT retainers W/O issues.

SOT is the way to go on street motors Smart choice guy...

Mine are also SOT. There is no way I would go with SUB on a street motor.

yes its nicer to adjust the valves on for sure. but 420 lift is max most do not like to use SOT with that lift when i set a head up with a 420in lift cam and SOT buckets i try to run the lash at .004in to try to keep the shims from shooting out from head. i also keep a close watch on my spring pressure set up. remember 83/84 GPZ1100 set up with SOB from factory.

Well in the two years that i have been running that motor now I have had it to 10.5K quite a few times if only by accident and by luck it is still in good shape.

otakar wrote:

Well in the two years that i have been running that motor now I have had it to 10.5K quite a few times if only by accident and by luck it is still in good shape.

otakar keep running her up to 10,500 rpm you have your spring pressures correct and your valve clearances set correct you will be good to go !

larrycavan wrote:

DFIGPZ wrote:

9am53 wrote:

Look at the bottom of this thread where Tim measured the GPz cams and says .375-.380. The .328 lift may have been the CSR or LTD cams, but I presume the .8mm increase your article states refers to a set of 81-82 GPz cams, or maybe a standard J cam

kzrider.com/index.php?option=com_kunena&...ew&catid=2&id=321585

i would say look at larrycavan post in the thread you posted #321743 he states GPZ approx 360 lift. buy them measure for yourself my 84 cams DO NOT measure 375 or 380 for whats its worth. in the end its all in what you want.

I measured a set for guy about 5 weeks ago. They were .365".

Good cam for small bore KZ900/1000 street motor.

Here's really the deal with those GPz11's.

Guys were hotrodding KZ1000 motors for quite a while with 1075 piston kits and 2x Andrews cams. A good ported KZ head with stock valves would flow mid 80's at 10".

Kawasaki basicaly delivered that setup in the 83 GPz11. A tad bigger bore, good head and DFI. They put out 104 rear wheel HP on Cycle Magazine's dyno test back then.

That's right in the neighborhood a typical 1075 with that combo puts out....

The more accurate way to measure it is to measure the base circle, then measure the overall height. Subtract the base from the overall. That's the advertised lift. You can subtract lash from that if you want.

Without taking into account the valve clearance I got .376". I measured both #1 and #4 lobes just to be sure and got the same thing both time.

DFIGPZ wrote:

yes its nicer to adjust the valves on for sure. but 420 lift is max most do not like to use SOT with that lift when i set a head up with a 420in lift cam and SOT buckets i try to run the lash at .004in to try to keep the shims from shooting out from head. i also keep a close watch on my spring pressure set up. remember 83/84 GPZ1100 set up with SOB from factory.

SOB for GPz cams was overkill. Then again, they had to warranty the bike :laugh:

It's the ramp angle that makes them SOB or SOT.

If you put magic marker on the shim and turn the engine over a few times, you can see how close to the edge of the shim the lobe makes contact.

The groove in the bucket surface is the shim spitting culprit.

If the lobe makes contact too close to that groove, it can rock the shim down into the groove....then it's bye bye shim.

You can modify the buckets.

I've had heads with 5x Andrews that were run with modified SOT buckets and raced every weekend without issue.

Nobody does it anymore but it used to be done quite often.

Larry C

i know this is back from the dead but the lift i measured on a pair of 83-84 cams i have is .387"ish. this would "somewhat" coincide with the info from a clymer that put's the cam measurement at 1.482" which with a believed to be base circle of 1.110" would yield a gross lift of .372", one thing i'm struggling with is the duration. with the cam in the lathe/live center, a chuck that's been degreed and mitutoyo indicator i'm getting much lower numbers than expected. with .050" of lift on either side of the lobe i'm getting around 106° which is 212° in crank degrees... can't figure out what i'm doing wrong.

this is what i'm coming up with, these numbers just seem way too short

212° @ .050"
224° @ .040
236° @ .020"

fwiw the megacycle catalog quotes (i believe at .040" tappet lift) the stock z-1 cams as being

.327"/237°
296"/229°