Yamaha Port tech

Rev Brown

Rev Brown

Member
Yamaha port tech....
So I don't have a Lad tech tool or the dimensions to make one. Can I use a drill blank and dial indicator to check port height. All advice welcomed.
ps. Still looking for a 787 cylinder and head.
 
It's well worth the $$$ to get the tool if you're going to be doing your own setup. I believe you can use different measurement values and a feeler gauge instead of the tool but if you're subject to tech, where they will be using the tool, it's best to do it like for like. It took me a good 10 min of messing around with the tool to even understand how to use it on the intake side, I'm not sure how you're really duplicate that with the feeler gauge
 
Use a .010" thick x .250" wide feeler gage. I believe you would subtract .100" from the intake measurement you get to check it against the WKA spec & you would subtract .100" from the exhaust measurement you get to check it. But, I could be wrong. It has been a long, long time since I used the feeler gauge method.
 
I've been told that using a .010" feeler gauge and dial indicator like it was done in the '80's yields the same results as the tech tool today. I still have the specs memorized for this method: exhaust - 1.060" intake - .875". As I recall, the intake check was self-policing because they didn't run worth a damn if you cut the piston skirt to .875". Maybe with a 787 cylinder that works?

If someone would be kind enough to measure the dimensions of the tech tool and post it here it wouldn't be hard to figure out the difference. According to my 2017 WKA Tech Manual, the port heights with the tech tool are: exhaust - 1.155" intake - .775". So it looks like the tool is about .100" thick?
 
"According too my IKF TECH manual it's .110
1/8th thick ."

So they took the old tech method of the .010" feeler gauge and added .100" to it for the tech tool. Apparently they gave the newer KT100's a .005" higher exhaust port at some point?

Thanks for the info Flattop 1!
 
"Apparently they gave the newer KT100's a .005" higher exhaust port at some point?"

I don't think so. I found my old tech manual from the late 80's and the book Racing the Yamaha KT100s. Both state 1.055" for the exhaust.

Some builders used to add .005" to their settings to accommodate a little flex of the feeler gauge. The port tool took that flex equation out of it.
 
I guess I didn't remember the measurements then, thanks for correcting me!

They say when you get old two things go away - your memory and something else.... I can't remember that one.... LOL!
 
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