KZ750 H2 valve clearances

I am working on checking the valve clearances on my 1981 KZ750H2. I have a service manual on it and the spec is .08mm-.18mm on both intake and exhaust valves. This means roughly .003-.007 in inches. I used the procedure that is in this factory manual and all of them are within spec but the number 2 intake valve is right on the bottom edge of this range! I can get a .003 feeler in it but it is tight but not to the point where you can't spin the bucket! Will this one valve require a cam removal in your guys opinion or will it be ok? Thanks for the help as usual!

lrburke wrote:

I am working on checking the valve clearances on my 1981 KZ750H2. I have a service manual on it and the spec is .08mm-.18mm on both intake and exhaust valves. This means roughly .003-.007 in inches. I used the procedure that is in this factory manual and all of them are within spec but the number 2 intake valve is right on the bottom edge of this range! I can get a .003 feeler in it but it is tight but not to the point where you can't spin the bucket! Will this one valve require a cam removal in your guys opinion or will it be ok? Thanks for the help as usual!

If it's an intake valve, it's probably OK. The exhaust valves get hotter and expand and contract more. The min spec on my 750 is .002", so .003" is no worries.

lrburke wrote:

I am working on checking the valve clearances on my 1981 KZ750H2. I have a service manual on it and the spec is .08mm-.18mm on both intake and exhaust valves. This means roughly .003-.007 in inches. I used the procedure that is in this factory manual and all of them are within spec but the number 2 intake valve is right on the bottom edge of this range! I can get a .003 feeler in it but it is tight but not to the point where you can't spin the bucket! Will this one valve require a cam removal in your guys opinion or will it be ok? Thanks for the help as usual!

Should be fine for a while.
Shimmed valvletrains don't go out of ajustment like the rocker arm set screw style does.
Sounds like a winter prodject.

Thanks a lot guys! I will get me a new gasket and 4 new cam plugs and button it up! The bike is backfiring when it gets hot so if this isn't the problem any other suggestions? I did a leakdown test on all four cylinders and 2 of them were only bleeding off 6% and two were less than 5%. It still has thirty year old coils on it that both are showing signs of getting real hot right where the plug wires come out. They both have blobs of black goo coming out from where the big phillips head bolt is. Any suggestions on where to go from here! Thanks again!

The coils have seen the day, get some new ones. That black goo is the Thermal insulation molded inside, not supposed to leak at all, toss em.

Ahhh
Black goo is not good.
Most of the guys here recommend Dyna coils but I cant remember which kind for the 750/4
Glad your valves are ok

Z1 Enterprises sells cheap OEM style four Ohm coils for $36 (I am running one). They will work on your bike but may not be optimum if yours has the electronic ignition designed for the lower resistance coils. But they are a lot cheaper than Dyna.

Here's what to pay attention to regarding the valve clearance. The first symptom when the clearance is starting to go out of spec is that the bike will stall when coming to an idle immediately after a fast, hot highway run. During the hot run the valve is at its hottest and most expanded (length wise). Right at the end of the higway run it will no longer seal so the bike will stall or run real rough. But just riding slower for a few seconds will cool it enough to be 100% back to normal.

You won't notice any symptom while on the highway because the vlave will only be leaking a very tiny bit. This timy bit will only affect idle.

So pay attention if you pull off a highway and come to a stop. If the bike stalls or the idle is rlow and rough, that may be the valve clearance.

Thanks a ton guys! I don't have a ton of cash right now so I am going to start with new wires and plugs. Someone put aftermarket wires in the OEM coils and two of them were really burnt on the end that contacts the pin inside the coil! I checked the resistance on the coils and the primary is right at 2.4 ohms on both and the secondary is 15,000k ohms on one and 17,000k ohms on the other. Within specs according to the factory manual right? I am still going to try the hairdryer trick to simulate getting them hot and see if that changes anything. I ordered a new valve cover gasket, new cam plugs, 7mm copper core Dyna wires and 4 new plugs this morning from Z-1. I did see the 36 dollar coils on Z-1 but am concerned about the resistance being wrong for my ignition! I would probably just get the gray 2.2 ohm coils from Dyna if I have to! Thanks again guys! I will reply again when I know something!

Going a shade high on coil resistance will still run OK, might have a slight difference at very high RPM but I have doubts anybody could notice unless you have a dyno. If anybody has tried the four Ohm coils with Kawi electronic ignition, I would be interested in hearing the results. I suspect they will run fine, but since I have not tried it, I can't say for sure.