Valve shim gaps -All equal or not?

So I'm at the valve shimming stage of my 1883 KZ1000J3 motor refresh.
Is it beneficial to have all the gaps approximately equal to each other when shimming valve gaps? Or just keep them in the .05mm to .15 mm Kawasaki service limits and be done with it?

Barney

Be as close to the middle as possible unless new valves are installed. I had to re shim after 500 miles. Some tightened up.
Steve

If using std cams get the gap between 0.10mm and 0.15mm.
0.10mm is the minimum clearance for these engines.
Aim as close to the upper figure as possible.

Zed.
The Kawy manual shows that .05 to .15MM is ok.

Barney

zed1015 wrote: If using std cams get the gap between 0.10mm and 0.15mm.
0.10mm is the minimum clearance for these engines.
Aim as close to the upper figure as possible.

To answer your question. NO they don't all have to be equal JUST within spec. Like Swest said, shooting for the middle is a good idea, so you don't run the risk of going out of spec too quickly.

The range is a factory tolerance with some built in play to make sure you don't harm anything. That being said if your bottom tolerance is .05MM and you measure .05-.06, I would consider stepping those up to around .10 since you are already working inside there and don't want to run the risk of the gap getting below tolerance. If anything is around .14-.15, I would just leave it there.

Sometimes switching a few shims around makes the whole family happy. And some folks check for decades and don't have to do a thing.

My comments are based on your .05-.15 reference (not all KZ share the same gap tolerance range, make sure you are looking at the Kawasaki Factory Service Manual for your bike model and year - not a Clymer or CliffsNotes). If you have a modified motor/cams/valves, your guess is the best!

barney wrote: Zed.
The Kawy manual shows that .05 to .15MM is ok.

Barney

zed1015 wrote: If using std cams get the gap between 0.10mm and 0.15mm.
0.10mm is the minimum clearance for these engines.
Aim as close to the upper figure as possible.

Forget the FSM.
0.10mm is the minimum unless you want to risk minus figures at high operating temperatures when running down to 0.5mm gaps.
There's also an increased chance of excessive seat wear (which translates into more frequent shim changes) and burnt valves ( especially the exhausts ) when running those low figures.

I would personally not run anything tighter that 0.08mm unless I was planning on checking the clearance very frequently.

However, I will say that, reading between the lines of the FSM procedure where you only change the shims that are out of spec, setting ALL of the clearances on a shaft to 0.15mm is not recommended (it can cause the cam shaft to rock back and forth and make a knocking noise and vibration). Wish they had mentioned that in the book so I didn't have to find out the expensive way.

In other words, 0.05mm is too tight period unless you check them every 1000 miles, and 0.15mm is too loose for more than one valve per camshaft side.

Thanks for the input

barney

swest wrote: Be as close to the middle as possible unless new valves are installed. I had to re shim after 500 miles. Some tightened up.
Steve

+1 You always want them in the spec range but leaning wider is better than tighter.

How is running 0.5 going to wear the seat faster then 0.10 ?

If anything running a wider clearance would cause more lobe wear
as theres more impact as the lobe comes off the base circle.

zukdave wrote: How is running 0.5 going to wear the seat faster then 0.10 ?

If anything running a wider clearance would cause more lobe wear
as theres more impact as the lobe comes off the base circle.

Good question. It seems counter-intuitive to me, so if it's true I'd like to understand the reason. Ed

Slamming effect.
Steve