Cam lobe base circle varies in clearance.

Here is some information. The tight areas are not on the base circle. Those areas care either the opening or closing ramps. Stock Kawasaki cams have very long opening and closing ramps.

www.tildentechnologies.com/Cams/CamBasics.html

As mentioned by the OP, and by me under another topic, the tightest spot is indeed at the base circle and not close to the opening ramps.

893cv wrote: Here is some information. The tight areas are not on the base circle. Those areas care either the opening or closing ramps. Stock Kawasaki cams have very long opening and closing ramps.

www.tildentechnologies.com/Cams/CamBasics.html

At TDC Compression stroke, those ramps won't be anywhere near the Lifter/ cam follower. You should be able to rotate the crankshaft 45 degrees and not hit a "Ramp".

I've read so many postings about this subject, but I don't really understand the problem as this is such an easy task on my bike. Maybe I'm just lucky, but using the Kawasaki Service Manual instructions always worked for me. Aren't the camshaft sprockets on the other KZ models marked in some fashion like those on the KZ650? On the KZ650 you simply align the line adjoining the "Ex" mark on the exhaust cam sprocket with the front cylinder head surface and check #1&3 exhaust; then rotate it until it aligns with the rear cylinder head surface and check #2&4 exhaust. For intake you simply align the "T" mark arrow on the intake cam sprocket to the rear cylinder head surface and measure valves #5&7; then rotate it until it aligns with the front cylinder head surface and check valves #6&8. You don't need to try to measure the base circle or find high & low spots or anything else that may confuse things. Ed

some people just think too hard! :woohoo:

Motor Head wrote:
At TDC Compression stroke, those ramps won't be anywhere near the Lifter/ cam follower. You should be able to rotate the crankshaft 45 degrees and not hit a "Ramp".

Yes, if you read the OP's original posting he states that at TDC and then with the lobe pointing directly away from the valve, he measured .1 mm clearance. Good, he is measuring the clearance between the shim and the true base circle of the cam. He then states " When I rotate the cam a touch more it gets tighter than .05mm." again, true. I bet if he keeps rotating the cam a touch the clearance will disappear, and if he keeps rotating just a little bit more the valve will begin to OPEN.

That sure sounds like an opening ramp to me.

Motor Head wrote:

893cv wrote: Here is some information. The tight areas are not on the base circle. Those areas care either the opening or closing ramps. Stock Kawasaki cams have very long opening and closing ramps.

www.tildentechnologies.com/Cams/CamBasics.html

At TDC Compression stroke, those ramps won't be anywhere near the Lifter/ cam follower. You should be able to rotate the crankshaft 45 degrees and not hit a "Ramp".

Thanks everyone. And thanks 893cv for the cam basics. I'm assuming I didn't have the right terminology to explain where my issue is. Or maybe like Wireman said "some people think too much".

So, here is a pic of what I'm trying to explain. Just to make sure everyone knows what I'm talking about. :lol:

I understood completely as this is common. Most guys just point the lobe away from the bucket and check there or use the timing marks and check there, and although this is the way to do it by the book and probably works fine, they have no idea there is variation by one complete shim size quite commonly while rotating the cam if checking the entire base circle clearance.
This was my question also way back in 1978. I was lucky enough to be friends and go to the same high school as Keith Pestotnik "the motorcycle man", who worked for Kawasaki and was a factory mechanic. He told me the way he did it, and that was to determine what valve clearance you are looking to get. Lets go with .10mm just as example. The way you would do it would be get a .10mm feeler and try to insert it while slowly turning over the engine with your 17mm socket on the crank. If anywhere in the rotation of the cam a .10mm fits then try a .15mm. If .10 fits and .15 doesn't you are OK on that valve and repeat on the next. He said most engines were set too loose going by the book procedure. Of course 1 size too loose is probably all we are talking about though.

Imo, the desired objective is to achieve correct clearance at the tightest base circle location.

Good Fortune!

RonKZ650 wrote: determine what valve clearance you are looking to get. Lets go with .10mm just as example. The way you would do it would be get a .10mm feeler and try to insert it while slowly turning over the engine with your 17mm socket on the crank. If anywhere in the rotation of the cam a .10mm fits then try a .15mm. If .10 fits and .15 doesn't you are OK on that valve and repeat on the next. He said most engines were set too loose going by the book procedure. Of course 1 size too loose is probably all we are talking about though.

Thanks Ron,

Do you have a recommendation for a clearance that I should go for? For example, if I set the tight area to .10mm clearance, that would mean the rest of the base circle would be sitting around .15-.17mm.

Thanks again everyone

Good, more information and a diagram. It looks like the other lobes on the cam are pushing the lobe you are measuring off center. There is no oil pressure to float the camshaft in the center of its bearings. Just use the Kawasaki Service Manual instructions ( that don't include anything about finding a tight spot) and you will be fine.

bobski911 wrote:

Motor Head wrote:

893cv wrote: Here is some information. The tight areas are not on the base circle. Those areas care either the opening or closing ramps. Stock Kawasaki cams have very long opening and closing ramps.

www.tildentechnologies.com/Cams/CamBasics.html

At TDC Compression stroke, those ramps won't be anywhere near the Lifter/ cam follower. You should be able to rotate the crankshaft 45 degrees and not hit a "Ramp".

Thanks everyone. And thanks 893cv for the cam basics. I'm assuming I didn't have the right terminology to explain where my issue is. Or maybe like Wireman said "some people think too much".

So, here is a pic of what I'm trying to explain. Just to make sure everyone knows what I'm talking about. :lol:

Attachment camshaftlobe_diagram.jpg not found

Some may not realize that this tight spot can be in a dif spot around the base circle,on each lobe. so if u just use the factory procedure , u would never know that u had a tight spot.