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case port work


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I was looking at some tecate cylinders that where portted for flat trac racing and there was a extra set of ports in the reed area of the cylinders going stright down into the case below the reeds not the thumb/boost ports to the sides. is this to add to the upper aux boost port when the piston comes down and pushes the fuel charge up the transfer ports? has any one tried it on a banshee?? :whoa:

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I put them in my Banshee cylinders, they work great. I have done several other sets too. I weld up the outside of the cylinders before even putting those in anymore, otherwise some of them break through to the outside.

 

The 250R motor has them in the stock cylinder too, they are huge.

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If I remember correctly the Kawasaki ports he's talking about are verticle from the cases to the reed areas along with another set of ports simular to my 12 port but not exactly the same and more restrictive than the 12 port....that set-up is actually based on crank volume instead of desired turbuelance of internal gases....Jim

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are you sayin that a kawasaki cylinder ported will not flow better than you 12 port system?

NO, Im definately not saying that. I am saying if the Kawasaki finger ports, or Honda 250R motors for that matter, were set up like the 12 port they would be flowing much better than they are. Remember, the Kawasaki and Honda motors have much larger reed assemblies and could be made to flow alot more than a Banshee cylinder, even my 12 ports. I was mainly referring to the verticle ports on the Kawasaki cylinders being a different philosopy entirely. Most added boost(finger) ports added to banshee cylinders flow directly into the transfer updraft bridge causing major inlet turbelence, Ive solved that problem. Not only did it solve that particular situation it also created positive effects on inlet flow of gases coming in from the main intake ports and also positive effects of updraft gases in the rear transfers. Anyone with a set of my 12 ports knows how I did it...Jim

Edited by PassionRE
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ok then my next question is that how is your 12 port system on the bottom end or when you roll off the throttle?an also when you port do you bench flow it?

When jetted in perfectly the 12 port stroker will make excellent bottom end and throttle response along with a very hard pull through upper rpm ranges. This engine piped closely produces a very flat torque curve from around 6000 through 9300 rpm and pulls to 10k before the pipes drop off. It also pulls tall gears easily with more top-end than most are really comfortable with. As for the flow bench, Passion is a very young company and gathering tooling currently to offer more product choices in the near future. Currently I am using the most productive method of designing engines available along with 25 years experience. I simply measure the angle of deflection of the roost bouncing off the upper one third of the helmets of the guys trying to catch one on a 1/2 mile shortrack...Jim

Edited by PassionRE
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[ I simply measure the angle of deflection of the roost bouncing off the upper one third of the helmets of the guys trying to catch one on a 1/2 mile shortrack...Jim

cool dyno

how does that compare to me seat-of-my-pants-jet dyno? can you give me some algebraic comparisons? :jesterlaugh:

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