TOPIC:

zed1015 wrote: Don't forget to factor in the thickness of the pressurised oil film on the bearing shells when the engine is running

That brings up a good point. We need to consider what type of oil should be used. Anyone have a suggestion?

loudhvx wrote: 3)The Kawasaki method, valve-to-valve difference:
The Kawasaki method the adjacent valve pressing down by one of two different amounts. Half of the adjacent valves will be pressing by about 1/2 of the valve travel, while other half of adjacent valves will be pressing by about 1/4 of the valve travel. I thought you said this resulting difference is about .001" to .002". My measurements did not agree with that at all. I posted all 16 measurements, where I measured each valve with the adjacent pressed by about 1/4, then I measured each valve with the adjacent pressed by 1/2. Since only one of eight valves had an actual difference in feeler measurement, we can very roughly conclude the actual difference is about .0002", which is far less than .001".

As I see it, we only disagree on point 3), and it's not about whether there is a difference or not, but only in the amount of difference.

Okay, I understand now.

So in summary, with the Kawasaki method the clearances will measure on the large end of the range and the Suzuki method more toward the small end.

When running (as the cam centers itself) the Kawasaki method clearance will close down and the Suzuki method will increase.

So suppose we have a worn head where there is .005" clearance between the cam journal bearings and the cam itself. Using the FSM method the cam will be shoved up in this clearance while adjusting the valves and the running clearances will be a fair bit less (.0025" maybe). Sounds a little scary...

Nessism wrote: So suppose we have a worn head where there is .005" clearance between the cam journal bearings and the cam itself. Using the FSM method the cam will be shoved up in this clearance while adjusting the valves and the running clearances will be a fair bit less (.0025" maybe). Sounds a little scary...

which is why the spec the engineers stated was for something bigger than that.

optimal is the engine will make most power with .002 clearance, and the valves will have seat time to cool off. IF I were racing a spec class, that is where I'd run them, and I'd check them every race.

However, the engineers gave a spec so that you only have to check them every 10k miles or so. they are a little loose so there is room for things to change a bit.

being real, 20-50 oil will have different clearances than 10/40. Adding an oil cooler will make the viscocity change. air temp will change cooling, which changes clearances. if you overheated it 20k miles ago, and the head warped a teeny bit. all that gets lost in the factory specs the engineers say to use.

"she's plenty loose at factory specs." to me this is like measuring air pressure in your tires to the .1. "I run 32.02 psi, and 32.22 is WRONG cuz the factory said to run 32,00"

FSM for Z1 and KZ900 calls for checking the valve clearances every 4,000 miles (6,000 km).

FSM for 1977-79 KZ1000 calls for checking the valve clearances every 5,000 km.

Good Fortune!

Nessism wrote: ... So in summary, with the Kawasaki method the clearances will measure on the large end of the range and the Suzuki method more toward the small end.

But I would assume that Kawasaki used the Kawasaki method when they determined what the clearance should be. So I would aim for the middle of the range using the Kawasaki method, and as you said, the middle to lower end of the range when using the Suzuki method on a Kawasaki.

I fear, however, many people have decided to aim for the very top of the range. Doing so will usually result in some being out of range simply due to rounding error, which is a problem with using the feeler method to measure gaps. (Not that I know of a better, simple method, but owners should be aware that feelers always give you a "rounded down" measurement, compared to the actual distance.)

Nessism wrote: When running (as the cam centers itself) the Kawasaki method clearance will close down and the Suzuki method will increase.

Yes, I agree.
late edit: I now see you mean running versus resting. I originally thought you meant running versus being measured.

Nessism wrote: So suppose we have a worn head where there is .005" clearance between the cam journal bearings and the cam itself. Using the FSM method the cam will be shoved up in this clearance while adjusting the valves and the running clearances will be a fair bit less (.0025" maybe). Sounds a little scary...

Well, I think that is a big "what if", but yes, it would probably be messy. But there is still the other bearing in good shape pretty near by, and we are not pressing the valve all the way to full lift force when measuring. It's significantly lower. So how much will the camshaft bend? Hard to say without measuring.

Also, with one bearing very loose, I would expect the wear on the adjacent bearing to eventually increase, even if just from vibration.

I see you're online now. I want to point out I made a very late edit to my reply.

I have a humble twin 750 B1. Not like you cool kids with the 4 cylinder hot rods. Following the FSM from 1976 I did the point the cam lobe directly away from the shim technique and got these readings:

RT Exhaust 0.08mm
RT Intake 0.09mm
LT Exhaust 0.09mm
LT Intake 0.10

Which puts them all within spec. Granted it's only got ~15000km on it but it's also 40 years old. Kawasaki tells me I should check/adjust every 6000km. Do the shims sometimes last that long or did I possibly screw up measuring the gap?

The ones I describe as 0.09 would take the 0.08 but refuse the 0.10. The other 2 took the 0.08 and the 0.10 just right

The correct gap can very easily last that long and much longer than that.

I periodically check the valve clearances on my KZ650-C1 and in 60,000 miles I have only adjusted 1 valve, and that was when my bike had 4,500 miles on it. The gaps on my valves vary only the slightest amount - sometimes getting very slightly wider and sometimes getting very slightly tighter. Other folks have had different experiences than this, but I've owned my bike since it was new (April 1977) and this has always been my experience. Ed

Last September (9 months ago) i had to swap out 2 shims but that wss the first time in 12 years and 40,000km. I generally check valve clearances every 12 or 18 months.
Dont know whst the PO did. Almost 79,000km on it at the moment.