TOPIC:

otakar wrote:

This is also not a true statement. Because all these new bikes have 16 valve heads they have lighter springs due to much lower reciprocating Wt. on them and also have lower lift than we use because they have a much larger combined surface area than in our bikes.

How much lighter are the springs though really. Say on an R1? They have to be heavy enough to get the valve back up at 17,000RPM reliably enough for Yamaha to set their redline there.

Anyways, I'm done arguing about this, I'll do my thing, you do yours.

if i remember correctly the r-1 has only about 35-40 psi seat pressure which is more than enough to return the very tiny light weight valves in a 5 valve head so there isn't alot of pounding going on in the seat and valve face area

What kind of seat pressure do we have Tim?

That would depend on what springs you have installed. Ask APE Jay what pressures his hi-performance springs will create. The KZ1000 is listed at 79kG nominal. The stock 1100 is listed at 76kG nominal. So I would guess that the hi-performance springs will approach close to 100Kg the 750 is listed at 47kG nominal with the smaller valves. So even between these two bikes there is a large difference. I know that the springs in the 650 are much lighter than in the 750 for sure.

OK I just got off the phone with Web-Cam and they gave me the # For the high performance springs that I have in my bike. The seat pressure is 97PSI and at lift it is 275psi. I believe that the Kawasaki pressures are also at lift. Which would make sense. Also I was told that cam ware is actually greater at lower than at higher RPM. This is the main reason you should "Never allow new cams to run at idle, 2K-2.5K is recommended RPM for the first half hour of brake-in". This is because at lower RPM the oil has more time to be squeezed out from in between the friction surfaces. They said that the rule of thumb is that if all components and conditions are equal than, the higher the RPM the lower ware on the cam face. This than brings another factor into perspective. Our revs are about half of modern bike RPM.

Makes sense. While you might never get full hydrodynamic lubrication on a cam lobe, the higher the RPM the thicker the film thickness will be. But, once you reach a certain speed, any further increase in RPM will not result in less friction. There is a point where greater increases in film thickness wont garner further gains. I wonder where that is.

From what I've gathered through some of my own research is basically the only engines that had any problem from lack of zinc was old V8s with rocker arms that put hundreds of pounds of pressure on the cam lobes. Has anyone actually heard of another instance of cam failure? I know my new goldwing has flat tappets and Honda says use oil SM or MA. They specifically say "do not add oil additives". No mention or worry of cams on a new engine regardless of whether car or motorcycle or diesel oil is used, just don't use energy conserving.

As Mentioned in previous posting. I put 275psi on my cam lobe at lift. Aren't those hydraulic lifters on a Lead Wing? They have a tendency to cushion the shock a little because a little oil will always escape.

T_Dub wrote:

Makes sense. While you might never get full hydrodynamic lubrication on a cam lobe, the higher the RPM the thicker the film thickness will be. But, once you reach a certain speed, any further increase in RPM will not result in less friction. There is a point where greater increases in film thickness wont garner further gains. I wonder where that is.

I would imagine that the valve spring tension will have something to do with that rev#. At some point you will wind up with some degree of float. The stiffer the spring that RPM will be higher. I also imagine that lobe profile will have something to do with it also. High lift Lo duration would be the worst Lo lift Hi duration would be the best. Everything els falls in between.

if i may chime in?i do not know how high performance a engine is in a police kz1000.should i be putting something in with my regular morcycle oil i buy from the dealer?i have 35000 miles on it!

If you use MC oil than you are OK. Most MC oils have the ZDDP required for a healthy engine. That is one of the reasons it is so expensive.