Oh NO! What have I done! My new KZ1300

Got the head off tonight and started to investigate the engine.





looks like honing marks on the cylinders, bore measures standard 62mm

Stripped the head down







The valves are telling me the story now, looks like the exhaust side was run too tight at some point. A few of the valve seals are defiantly leaking. The guides may be ok, measure about .004-.005" play with the wiggle test.





Nothing a good valve job can't solve...

Pulled the cylinder bank off tonight, and took the pistons off.






There are signs that someone had the top end apart, pattern head gasket, honing marks in the cylinders and some tool marks on the timing shaft. Obviously they ignored the head, not sure what they did to the cylinders. The pistons look good, but the rings feel too soft, not the proper tension I would expect. The oil rings really don't feel right and they don't seem to expand like they should. I wonder if there isn't an aftermarket ring set or something going on. I will pull out the bore gauge and see what I have.

Pistons are a real bear to find for these bikes. JE can make them for a small fortune... but Weisco may have a solution for me. Jeff Saunders from Z1 steered me thier way and there could be a possible solution. I have no specifics yet but Weisco requires a minimum order of 12 pistons, that just 2 sets for the 1300. I can probably find another owner or 2 out there looking for parts and make this happen. Cool stuff!

The cylinder head got boxed up and shipped to Larry C.

Megacycle can do my cams, but I want to do just a bit more research before I send those out.

That bike is going to be sweet when you finish!

Quick measurement of the critical head areas show typical OEM specs. Intake throats are 83% of the valve diameter and exhaust are at 80%.

Ultra long, tiny port runners with small throats are probably not going to be impressive when I flow it. Carb synch tap bolts protrude into the roof of the runners, some more than others. Improvements are going to come from the area near the valve seat.

I will post you some numbers after the holiday weekend. Downloading a 296MB manual to get valve installed height specs and spring data.

Do you think they made the cam chain tunnel wide enough :lol:

It will be fun to see what you can do with it Larry. As you suggested I found a source for exhaust valves. I ordered a set of Vesrah ex vales from the UK. The intake valves are available here in the US.

The cam chain tunnel also includes space for the shaft the drives the water pump,

As far as other work goes, I ordered some parts up for the water pump shaft seal, the cam chain sprocket on the tensioner, an some of the other odds and i need to put the top end together again. All I need to focus on now are the cylinders and pistons.

Started the cylinder inspection tonight...





I bought this nice bore gauge set up from e-bay. I have used snap gauges form bore measurements in the past and they do work, but they are a real pain in the ass. I figured it was about time I owned nice one. I set up a stack of gauge blocks to set a micrometer to, and then set the bore gauge to the micrometer. I measured each cylinder and re-checked my bore gauge to the mic form time to time.







Its not bad, it would run with a simple hone and re-ring. Honing will not change the dimensions, it just a surface treatment.

The nominal bore size is well within tolerance however I got a few maximum out-of-round measurements at .0012" and maximum differences of .0015" on a few. The service manual lists .002" as the service limit. If I absolutely cannot get pistons, I could run this assuming the pistons are good. I would prefer to bore these out and do it right though...

That is a AWESOME bike!!!!!!

Got it on the flow bench today

Stock & A Little bowl work @10" with clay mock up on runner entrance
More to come yet

#2Intake [straightest looking port]

Lift Inch CFM1 CFM2
0.1 31.02 33.07
0.2 55.77 61.62
0.3 69.66 73.43
0.4 69.72 75.15

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Neat stuff Larry, Do you measure the velocity profile across the runner diameter, or use some other method to compute the volumetric rate?

Tyler wrote: www.facebook.com/photo.php?v=901407429875616

Neat stuff Larry, Do you measure the velocity profile across the runner diameter, or use some other method to compute the volumetric rate?

What you're after in flow testing is 3 things. CFM, CSA & local velocity. You can derive a cross sectional area measurement with simple math formula when using the pitot tube. You can see CSA in the video on the right hand side of the live numbers on the screen.

You can also calculate the average CSA by measuring the port roof & floor, add together, divide by two. Then cc the port with a burette and apply another formula.

Velocity is a simple conversion from inches of water column to feet per second using another formula. In the software I built it all in so it gives me a direct reading on the screen. Saves a lot of time and number crunching with a calculator.

I'm not going to push it with this head for two reasons. Water Jackets and your stock carburetors with limited tuning components available. The head signed off at .350" lift. You can see that in the numbers. It's already gaining at .400 with a little work so that's mainly the target. That way you'll take better advantage of the cam lift increase.

Getting some bowl volume in a hemi head always seems to improve performance because it works in favor of pressure recovery. You want to convert velocity pressure back to static pressure as the air enters the cylinder.

I see, Back in school they made us measure various ducts and compute flow and head loss, etc. We had to do all the nasty integration by hand, the momentum equation can be a real bear...

One thing I worked on while in Grad school was trying to match surface finish to boundary layer thickness and the onset turbulent flow development, not really possible to do with the computer simulations available today.


...Anyways looks pretty clear that Kawasaki matched their cam, valves, and runner size pretty well from the factory. Going to a .375 lift with the re-grinds makes sense now.

Does opening up space behind the valve help low end torque and throttle response as well?

It could.