Bore and Stroke dipstick

[Magneto]

New guys here and I'm sorry if this has been asked before, but I was unable to find the answer.
I have a Kawasaki KZ650, which is an overhead cam engine. The spark plugs are in the middle of the cylinder but they are in at an angle, possibly 45 degrees. Can you measure the bore and stroke with the dipstick, or would I have to pull the head if I managed to beat a current record?
Thanks for the reply.
Mag

[Stainless1]

The dipstick tool will just fit through an 8mm sparkplug hole.... it must be straight to the bore to measure... get a 5/16 dowel rod... if it can be aligned to the bore then it can be measured. 

[donpearsall]

Hello Magneto welcome to the group!
The bore measuring device must be inserted into the spark plug hole so that it is parallel to the cylinder for both bore and stroke measurements. I think it is about 1/4-3/8" in diameter.
So you might want to see if that can be done given the angle of that engine's spark plug holes. If the angle is very slight it might work.  Another issue is if there are things in the way such as the frame. A few years back I got a record on a Kawasaki ZX-10 but part of the frame was in the way. The only way to avoid spending all day taking the head off was to grind away the part of the frame that interfered.

I wish there was a better way to do it. It seems like the technology is there to get it done but I have not seen any high-tech laser gadgets that can measure bore and stroke. At SCTA they measure cars using some sort of oil displacement process.

Don

[7707]

A stock 650 has a bore and stroke of 62mm x 54mm

[Stainless1]

The SCTA also used to measure motorcycles with oil... you had to pull the cam or disable the valves. They had a graduated burette filled with auto tranny fluid... it took a while to get the motor started after measurement.... especially if they measured more than one.

[panic]

Have a nice day

[edinlr]

Magneto, be sure to read the post above about the bore and stroke.  Your motor displaces 652cc, so you will run in the 750 class.

[Interested Observer]

The stroke length = cosine of thread angle X probe depth

Assuming a clean, flat-topped piston that doesn't rock in the bore.

[panic]

Why?

[Seldom Seen Slim]

I had to dig, but I found these pics of my ZX12 displacement being checked with the oil pump device in 2003.  Clem and I-can't-remember-his-name from ECTA assisting, and Tom Evans and good ol' what's-his-name officiating.  Yes, we did have to disable the cams.  Yes, the job also including loosening the engine so we could rotate it forward to allow access to the plug holes.  Yes, it was a royal pain in the patootie.

[salt27]

Jon, I remember watching what Todd went through to get the engine in your ZX12 ready for measurement at Bonneville and decided that I would never complain again about having to pull the head on my bike for measurement.

    Don

[donpearsall]

When I last was at the dentist he had a tiny camera that scanned an exact 3D model of my whole mouth in about 30 seconds. From that he was able to make a replacement tooth that fit exactly. So the technology is there to measure bore and stroke from the sparkplug hole. Now we just need to find someone to build it.

Don

[Joe Timney]

Clem and I-can't-remember-his-name from ECTA assisting.

Clem Robert?s, from No Class Racing!
Joe

[Seldom Seen Slim]

Ah, yes - Clem of the F 250 with a sequential-turboed Cummins and the moonshine offered generously at the Pine Acres.

[AHG]

Hello "Magneto",
To answer your question specific to the Bonneville Motorcycle Speed Trials only, the bore and stroke tools can only be used if the spark plug hole is centrally located and parallel (not angled) to the bore. If not, the cylinder head must be removed. If you have any further tech. questions relating to that meet, regarding AMA and or F.I.M. you can reach me at gears55@frontier.com
Hope this is of help.

BR
Drew Gatewood