Thats nice .Here is the other KT with 4 port exhaust. It was by Cook Racing.
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Sean Cook stated this modification is based off the Parilla TT-36 & Komet K-30.
Brian #89
I consider eyebrowing arching and/or widening the exhaust port around toward and above the rear transfer ports. I have never cut on the piston above the ring. I like to keep my squish uniform. The only piston eyebrowing I know to do is to cut on a 4-cycle piston to give the intake & exhaust valves room to open for high lift camshafts.With the many differnt definitions of eyebrow .
Arching the top of the port or cutting the port at an angle to get the increased port height/ time duration ?
There is also eybrowing the piston .
Raising the overall port height would that be considered eyebrowing ?
Adding more area, widening the ports, or raising the ports, more area, should be the same.
Another thing, add counterweight to the crankshaft. Big performance gain.
Personally, on the KT100, no.Al,
Have you actually tested this on a KT100?
PM
You're absolutely right, as always, still, people have been adding weight to the crankshaft without knowing what they were doing for many years. Myself included. Gil Horstman made the counterweights that I used in my McCullough, they seem to work out, maybe he did the math. Maybe Mark did the math before adding weight to his Yamaha crankshafts? Maybe Kyle Atkins too. In any case, it seems to have been beneficial.I guess my comment would be... simply stating "add counterweight to the crank" is a bit of a crap shoot if the balance factor is not known to begin with.
PM
How did he do his reeds?I owned a Buller SA that had internal hidden reeds and a turbine style crank.
Glad to see you still have these Brian, the motor withe the sticker was the strong one and that one carb went on what ever motor I was running. BarryI've got a couple of these but, no reed valves. It does have a special WB3A on it. I liked the carb so well, I had it copied so now I have 2.
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Brian #89