KZ900 A4 FRUSTRATED- Can't get valve timing right

Katums wrote: Yes, valves adjusted before carbs. I'm hoping I won't need to order shims, but I'm guessing I will. Valves today.

Is it common to need different sized (thickness) shims for each valve?

Yes, you will need some shims and there will be a variety of thicknesses in there. Sometimes you can get lucky and swapping a shim from one out of spec valve to another will bring one or two into spec without replacement. You will have to know the thickness of the shim on the out of spec valves in order to know what thickness you need there. Once you know what is in there and what is needed, you can determine if a swap or two is possible.

Would you recommend renewing carb kits or should cleaning be sufficient? I took off the top and bottom caps just to inspect and they are crusty with white residue.

As a rule, all that needs to be replaced are the soft parts - gaskets and o rings. Sometimes a needle and seat will need replacing. The factory parts are hard to beat when available.

Thanks so much for your advice.

I have to say, this list is extraordinary in the knowledge and willingness to help others.

It would be great if all of society work this way.

Ed

On the VM carbs there is very little to go wrong. A light smear of grease on the gaskets can seal them. My 33's are 40 years old. Try cleaning them up first.
Steve

Steve, will do, I will clean everything up in the carbs and see how things look.

Since my last post, I checked the valve clearance and cannot get .002 under an lobe at any turn of the cam. It looks like I'll need a lot of shims, but now my question is, how can I order shims if I can't measure any tolerances?

I believe the ones currently in place are 28mm and I think they are all the same, probably stock.

I'm a little worried that there is "0" clearance under any lobe. Should this be unusual for a bike that's been sitting? Could something something else be up?

Thanks,
Ed

They are the most neglected. Can you spin the buckets with your finger? If they will turn, I'd get two sizes down. Say 265 to 255.You can get them from a lot of places.
jetsrus.com/individual_parts/KL_13_7646.html
Here's one example. You'll need the tool.
Steve

Great tip, I'll check if I can move them with my fingers. I suppose there will be some trial and error with ordering them given my findings. I ordered the tool.

Ed

I have a "golden shim". It is the thinnest one I could find.
Every head I've tried it in with no clearance, gives me a very large gap.
Once I know that large gap measurement using that "golden shim" number ...again, in any given bucket, I can use the factory chart to figure out what shim will give me the proper .002"-.004" clearence.
I don't actually use the chart anymore because the math is too simple but if this process is rather new to you, use the chart.
You can do the same with any shim that has some gap to measure of course...

Katums wrote:
Since my last post, I checked the valve clearance and cannot get .002 under an lobe at any turn of the cam. It looks like I'll need a lot of shims, but now my question is, how can I order shims if I can't measure any tolerances?

I believe the ones currently in place are 28mm and I think they are all the same, probably stock.

Shims are 29mm.

To calculate shims needed if you currently have no clearance -

1. Buy one 2mm shim (that is the thinnest) and methodically substitute it for each shim in the head.
2. Measure the clearance of each one as you go.
3. Deduct 0.15mm from each reading and add the remainder to the 2mm shim you have used and this will give you the shim sizes you need.

I.E.
Clearance with 2mm shim fitted = 0.55 mm
Minus 0.15mm = 0.40mm.
2.0mm + 0.40 = 2.40mm.
Size of shim needed is 240 for that valve.

Hopefully you don't end up with figures too much lower in the range or you are looking at tipping the valves to regain clearance in the near future.

Katums wrote: Since my last post, I checked the valve clearance and cannot get .002 under an lobe at any turn of the cam. It looks like I'll need a lot of shims, but now my question is, how can I order shims if I can't measure any tolerances?

I believe the ones currently in place are 28mm and I think they are all the same, probably stock.

I'm a little worried that there is "0" clearance under any lobe. Should this be unusual for a bike that's been sitting? Could something something else be up?

Thanks,
Ed

Katums,
We'd be a little surprised if there are no valves that will accept a .002 feeler. We keep a .0015 feeler in the shop to see how tight a borderline valve might be. We'd like to clarify what it is that you're actually measuring.

You indicate there are no "lobes" under which a feeler will enter. The "lobe" is actually the portion of the cam that consists of the ramps, nose and lobe center. The lobe center is where mamimum valve lift is realized. See the illustration here:

www.speedwaymotors.com/the-toolbox/camsh...nd-terminology/28647

Correct valve lash is measured from the base circle. We always measure valve lash with the cam nose/lobe center pointed directly away from the shim. This will assuredly be on the base circle of the cam profile. In reality, measuring lash anyplace around the base circle should give an accurate lash measurement, but it can be difficult to ascertain where the ramps begin to lift away from the base circle.

Good Ridin'
slmjim & Z1BEBE

Sure enough, all of the buckets will rotate with figure pressure. Great call, Ill start looking for the shims.

Another general question: This machine sat along time, 15 years and wasn't always kept dry. I'm replacing a lot of rusty hardware and cables and such. I drained and changed the oil and put a new OEM filter in.

So, where else do you think I should be looking to renew or maintain? I intend to clean and go through the carburators, of course.

What's amazing to me so far, is how good the steel quality is. I've removed a lot of rusted hardware so far, and only snapped one bolt in the front brake handle. Some nuts and bolts looked like they were sure to snap, but so far, so good.

Thanks once again.

Ed

To clarify, I am measuring in the base circle area and not actually on the lobe. In fact I measured at various low points, but do realize I should be measuring where and when the valve is colored, so yes, I'm measuring in the circle as depicted in the link you so kindly sent.

I too was surprised that I couldn't find any valves with clearance, but on the other hand they seem equally tight to the best of my ability to measure at this point. However, I do have compression in all 4 cylinders, so the valves are closing enough to generate compression.

But, this bike is a total mystery, given it sat for 15 years and hasn't run probably for longer.

Thanks once again.

Ed

Hi Kats,

Can you post a few pics of your bike? A few areas you want to check are, the swingarm pivot bushing, wheel bearings, steering head bearings, brake caliper pistons, master cylinders and for sure flush out that fork oil. One thing I always do before tearing down any engine is check all my valve clearances and write them down for reference, keep a log book specific to that bike. When reinstalling cams be sure not to get mixed up with your ignition rotor marks as their is a 1/4 TDC and another mark to the left for your ignition. I always turn the engine over by hand using the large nut on the end of the crankshaft @ 6 times or so with the plugs out to make sure valve assembly does not bind or get familiar with the pistons... just to make sure.

Doug