n2otoofast4u Posted November 27, 2016 Report Share Posted November 27, 2016 What's pwc?Personal Water Craft Lake lice Quote Link to comment Share on other sites More sharing options...
sleeper06 Posted November 27, 2016 Report Share Posted November 27, 2016 That's funny shit green , I live rite by the jones inlet most of my customers are stand up guys that do freestyle in the ocean and I do a lot of gp1300 , I've got the gps down to a science . Dealing with marine people is very different , they don't bat an eyelash at a $1200 port job where atv guys bitch about $300 1 Quote Link to comment Share on other sites More sharing options...
Dunatic619 Posted November 27, 2016 Report Share Posted November 27, 2016 That's cuz banshee owners are a bunch of broke d!cks. I'd pay $300 for a sleeper pot job all day! 1 Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted November 27, 2016 Report Share Posted November 27, 2016 As soon as he said "main jet" I assumed that he had the Trinity PVs. I've never seen a Rotax one modded to us a main jet.Exactly Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted November 27, 2016 Report Share Posted November 27, 2016 Tricked, do you have any better pictures of the valves side by side. I'll pm you my cell and email if you wanna share I would be very interested in seeing the amount of machine work necessary to a proper fitment . I cut my teeth on pwc and still work on quite a few. The power output on pwc twin is awesome and on point as soon as you touch the throttle.I'll see what I can find. Quote Link to comment Share on other sites More sharing options...
trickedcarbine Posted November 27, 2016 Report Share Posted November 27, 2016 Nice looking motor. Alu. frame?Not sure, it's an Aprilla with a 421 cheetah. Quote Link to comment Share on other sites More sharing options...
Thack82 Posted November 29, 2016 Report Share Posted November 29, 2016 My Cheetah uses the Trinity Billet Power Valves Trick. I was refuting to them as Rotax Style because they are driven by the exhaust pressure generated by the engine during the combustion process VS a mechanical power valves that are driven by centrifugal weights and spring pressure that are attached to a internal linkage that's driven by the crankshaft, or a servo motor that's controlled by the ignition. I can see how that could have been confusing because the exhaust pressure has to overcome tension created by a spring and the billet power valves that my Cheetah has to overcome a metered portion of the exhaust flow. I apologize for the confusion. I don't see any reason why actual Rotax Power Valves couldn't be used on the Cheetah, all that you'd need to do is have the Rotax Power Valve Slides machinined to match the Trinity Power Valve Slides. As far as I know the Rotax version would bolt up on the Cheetah Cylinder's without any other modifications. Quote Link to comment Share on other sites More sharing options...
Thack82 Posted November 29, 2016 Report Share Posted November 29, 2016 It was my understanding that the bigger 72mm Super Cubs and Super Serval's encountered some head gasket issues that were attributed to domes not being machined properly when they first introduced just like McDurmott had with the Cheetah. The Cheetah was/is designed and manufactured by Calvin at CP Industries just like the Cub, Serval, DM Cheetah, ect. McDurmott just bought the exclusive rights to that particular setup believing it had the means to be the ultimate power plant for a Banshee. I think he put the Cheetah on the market before they had all the issues figured out and that combined with a lack of knowledge on power valve exhaust port porting characteristics, and the fact that none of the exhaust builders had developed a set of pipes to work with and compliment a power valve engine all came together to create the Cheetah's demise. If you step back and look at everything the Cheetah offers it has to fall back on those three things. What features and design characteristics does the Cheetah have that make it less desirable than a Super Cub or Super Serval other than overall cost? The bigger six bolt 250R intakes can't be a bad thing because the intake issues that have limited and plagued the 521cc+ Super Cub and Super Serval has been well documented since their release. The Cheetah is a 26 port Mono-Cylinder with the same or very similar to the port timings CP used on their DM Cheetah that's been a proven performer in the Banshee racing world since its debut, and the exhaust driven "Rotax Style" Power Valve's have been used and proven to be effective and offer a distinct advantage over non-power valved two stroke power plants that were used in Snowmobiles and PWC's for years until the production of two stroke engines was brought to a stop by the EPA do to their inability to meet the current US emission laws. So the way I look at is the problem has to lie with the additional cost associated with building the Cheetah and the three issues I mentioned previously. If you overlook the additional cost associated with building a Cheetah and get a new untouched set of Cheetah Cylinder's in the hands of a capable builder that's knowledgeable on the mechanics of a two stroke power valve engine equipped with that particular type of power valve there is no reason the Cheetah can't be capable of being the top performers as long as it's equipped with the right set of big bore pipes that are designed to complement a engine that has variable exhaust port timing. Those are the things I took into consideration when I decided to build a bullet proof 10 mil trail motor. I was deciding between the 535cc Cheetah and the 521cc Super Serval and I decided the Cheetah was the best option for me and what I was trying to accomplish with my bike. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted November 29, 2016 Report Share Posted November 29, 2016 Thack, did you happen to dyno your motor yet? Just curious. I have a 496 (72 bore 7mil stroke) I'm fairly happy with it but I'm still tuning it in. Right now I have cpi small bore inframes on it and I think I have to go big bore. It seems like the pipes are heat socking after a little bit of riding. I have been looking to see if there was any different power valves that I could put on because I'm not happy with the way the trinity power valves are designed. Mine just don't seem to want to seal very well. But I will say running it with the power valves vs running the block off plates is night and day. Extremely smooth power delivery. Sent from my VS990 using Tapatalk Quote Link to comment Share on other sites More sharing options...
LaegerEliminator Posted November 29, 2016 Report Share Posted November 29, 2016 Any word back from Duncan? Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted November 29, 2016 Report Share Posted November 29, 2016 Thack, did you happen to dyno your motor yet? Just curious. I have a 496 (72 bore 7mil stroke) I'm fairly happy with it but I'm still tuning it in. Right now I have cpi small bore inframes on it and I think I have to go big bore. It seems like the pipes are heat socking after a little bit of riding. I have been looking to see if there was any different power valves that I could put on because I'm not happy with the way the trinity power valves are designed. Mine just don't seem to want to seal very well. But I will say running it with the power valves vs running the block off plates is night and day. Extremely smooth power delivery. Sent from my VS990 using Tapatalk You have the wrong pipes. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted November 29, 2016 Report Share Posted November 29, 2016 What pipes should I have? Sent from my VS990 using Tapatalk Quote Link to comment Share on other sites More sharing options...
guns4children Posted November 29, 2016 Report Share Posted November 29, 2016 I can't even find any PV cylinders. I've been looking just for fun and it seems like everyone stopped making them. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted November 29, 2016 Report Share Posted November 29, 2016 I can't even find any PV cylinders. I've been looking just for fun and it seems like everyone stopped making them.I have some Twister Sniper power valve cylinders 840 cc give or take. Quote Link to comment Share on other sites More sharing options...
rjdgriff Posted November 29, 2016 Report Share Posted November 29, 2016 Do you guys actually read those BOOKS that thack has been posting? HOLY SHIT Sent from my iPhone using Tapatalk Quote Link to comment Share on other sites More sharing options...
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