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Old 10-16-2005, 12:22 PM
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Default RE: Extreme Flight 87" Yak 54 - Build & Fly

I am using the KS-1060 tuned pipe.
That is an excellent tuned pipe for this engine, and knowing that, what I said above definitely applies. Did you setup your header length as suggested by KS? Tuned pipes are critical as to header length, and more imporantly than that, you need to be sure you're getting your engine into the pipe's powerband, which is typically very narrow. KS's turned canisters have a much wider useful powerband, but don't give near the boost. That could explain the low RPM you're getting. I'm guessing you need to be turning the engine in the high 7's to take advantage of that pipe. I'd recommend you try a 22X8 Mejzlik, and I'll bet you'll be turning in the upper 7's. I tuned pipe is really not the best thing to be running if you want to run bigger props on this engine, unless of course it's a tuned pipe designed to benefit most at lower RPM ranges, which is not typical for tuned pipes.

was playing with the throttle ATV and the prop started ripping so I stopped.
BTW, if you're not getting full throttle, that certainly could be the culprit with the low RPM. All props rip to some extent, though some more than others. You may want to switch to a Menz S instead of the Mejzlik if the ripping is bothering you, but remember they are higher-load props and you'll need to run about 1 size lower than a Mejlik to get the same RPM numbers. Even with a Menz I'd go with a 22X8 with your pipe.