Cam lobe base circle varies in clearance.

Great, a lot of good info. So here is the deal. I'm tired of taking the cams off and switching shims around. Last week I checked the valves because my bike was idling very low when ever the engine got hot,(20min ride). Turns out 3 valves where tight, .05mm at TDC, and one loose .21mm. So I made the changes according to the book at TDC, at got ranges between .10-.15mm. Bike ran great, but once it got hot, after 1 hour of riding, the idle started to stumble. This is when a mechanic told me that I should measure off the tight areas on the lobe. So I did, and got my clearances at .08-.13. When I started the bike it sounded fairly good but noticed some ticking. I took the bike for a ride and it rode great with more power and better throttle response. But as the engine got hotter, the ticking got louder. So I went home and this is where I'm at. :S

I guess I'll give it another go this weekend. I really appreciate everyone's advise and help.

if i have a big dif. from the tight spot and the loose spot , i set the tight spot at the min spec. it takes a lot of miles for the valves to sink enough to need to change the shimms again.

make sure u adjust tha cam chain too (if its not an auto tensioner).

893cv wrote: 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.

You got a very good point 893cv. I think its strange that some people say the cam base circle is perfect on Kawi bikes, and some people say they are not. I know that lobes 1&4 seemed to have the tighter spots then 2&3, but I will need to check that again. That would make sense that one end of the cam would be pushing down, while the other end pointing up. Interesting :huh:

it has nothing to do with instalation of the cams. they r just ground inacuratly.
some people think the ma kawi ballances there engine parts perfectly too. Not so.
when i had my KZ's clutch basket ballanced,it was out 2 grams. the guy said that race teams bring in there brand new zx baskets and cranks in for ballancing. the new baskets can be out 7 grams. things are not as well built as u may think.
My new MTC piston need tuning as well. they had a dif of a couple grams.

bobski911 wrote: Thanks wireman, but what I'm wanting to know is what should I set the clearance too with these tight spots being on the lobe. It seems the difference between pointing directly away and the tight spot is .05mm or more. So, if I set the clearance at .08 at pointing directly away, there is potentially a point on the lobe that is .03mm or smaller.

Thanks

What you have to watch out for is measuring too close to the opening ramp. Measuring with the lobe directly away from the bucket assures you won't do that.

You can use the lines on the sprockets to check more than one valve at a time. That's what those lines formed into the rubber cushion on the sprockets is for.

You may well get some variance between doing it that way vs lobe away method. As long as you have lash along the base circle that is at least .004" you'll be fine.

Let's say that when measuring using lobe away method you get .006" for lash. Then you rotate the engine in running direction a few degrees and that lash tightens up to say .004". It's not really going to affect anything you're going to notice on a stock or mild engine.

I've seen a lot of used Andrews cams like that, some with even greater variance that .002". There's a potential for having a noisy valve tick if you get a really out of shape lobe. In a case like that, you have to take it for what it is and adjust accordingly.

Generally, stock cams don't provide much of an issue. If you have a set that is that worn, there are lots of stock cams around the country to be had for a song. I threw away probably 25 sets last fall.