Actually he filled parts of the ports with JB Weld!



It's at half page here. That's all he has to say about the KLX engine work.

 

Maybe this bike is the one MotoTune did the porting on. It's the second story on the page, and most of it runs down the right side..


The big 365 is using a 35mm FCR carb


Though this bike was built back in 1997 - well before the advent of the Mikuni pumpers I'd think.

 

I'm glad I didn't bother taking anything OUT of my ports.

Anyone still interested in deshrouding, compare the valve areas in that head to stock...

Makes me feel a little better about my hamfisted efforts.

 

That's a 10 year older KLX than the S model.. I wonder if Kawasaki upgraded the port design from the '97 for the 2nd generation S model?

You have to be careful when choosing epoxy to add to ports. JB Weld doesn't like alcohol so ethanol gas might have it coming loose. Moroso A&B epoxy is recommended in online forums.

 

IMPOSSIBRUE !!!!!!

even stock KLX ports cannot flow the massive amounts of air and fuel required for big bore and cams.

 

Speaking of porting etc, I enlarged my 2 intake manifold bolt holes slightly to I could optimize its position on the flange by mounting it a little lower. That aligned the bottom of the intake's hole with port floor better, and at the same time let the upper arc of the intake's hole match up better to the port edge behind it; covering up the little bit of flange edge that had been hanging down into the port.


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The mototune guy has been going on about the port size and everything I've ever read goes against flat out hogging out ports for flow. I have only done a bit on a four stroke, cleaning up some on a port, but no porting since I don't have the right equipment and would have just ruined them by opening them up.

Most all four stroke head work now is taking velocity into account over sheer flow. High flow but low velocity doesn't work as well as a bit lower flow but high velocity. High velocity can move more volume overall and keep more in the cylinder as the valve closes, stopping more blow back of the charge.

The change of the direction of an intake was done some decades back on the SR500 head with its poor design making the bend tight. Making the port D shaped is another method to deal with the tight bend. In D port heads the port is relatively large, but chopped on the bottom eliminating the slow velocity flow on the bottom of a round port by using a raised floor as shown in some porting examples.

All those things are reasons why I'm not going to take on grinding up my heads on my bikes - I understand some of the theory and applications, but that isn't the ability to do the work.

 

Another Motoman convert (YZ250F) from 5yrs ago

I tried Motoman's porting... - General Dirt Bike Discussion - ThumperTalk