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Thread: Ct350pv?

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    Ct350pv?

    I have a ct350pv. It has their power valve on it. Wondering if it is possible to change it to the total style valve. Jerry or Neil your guys knowledge would be appreciated.

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    I am not sure what you mean by a "total style valve". All of the power valves I have seen on the CP Industries and ESR cylinders are operated by pressure in the exhaust system. The best way to operate a power valve is with a computer controlled servo motor that is laptop programmable where the power valve position depends upon RPM and throttle position. One of the big problems with pressure controlled power valves is they fully close at partial throttle when the engine RPM is high enough that they should be partially open to fully open.

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    Racer Langbolt's Avatar
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    Jerry....Like a 2003 CR250R ?

    Too bad Honda didn't keep the 2-strokes alive....would have been nice to see this setup on our 'R's.....I wonder if Eddie ever thought of trying this type of Power Valve control ?


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    Sorry auto correct on my phone got me. I'm wanting to put the rotax style on it.

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    Quote Originally Posted by Langbolt View Post
    Jerry....Like a 2003 CR250R ?

    Too bad Honda didn't keep the 2-strokes alive....would have been nice to see this setup on our 'R's.....I wonder if Eddie ever thought of trying this type of Power Valve control ?

    I sure he thought of it but....... Doing it right with stepper/servo motors like the late model CR 250 or the Yamaha road racers with a programmable box would cost more than ESR cylinder kits. Most of the guys buying the ESR cylinder kits don"t have the budget to do it right.

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    I do realize that style of pv is best. But this is the style I have to work with. From my understanding the rotax rave valve is the best working. So this is the reasoning behind wanting to put it on the one I have.

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    Racer Langbolt's Avatar
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    Didn't Pro-X use the Rotax design ? Aren't they inter changeable ? Do you have access to a Rotax one to compare ?

    Looks like FTZ uses the Rave Valve on the Pro-X Cylinder

    https://ftzracing.com/PowerValveMtr.php

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    Pro-X broken1's Avatar
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    Quote Originally Posted by Langbolt View Post
    Didn't Pro-X use the Rotax design ? Aren't they inter changeable ? Do you have access to a Rotax one to compare ?

    Looks like FTZ uses the Rave Valve on the Pro-X Cylinder

    https://ftzracing.com/PowerValveMtr.php
    The Pro-X cylinder I got has a rotax pv on it but I didn't get it new so not sure if thats what it came with or not. It's an LRD Pro-X 265PV.
    overkill is an often underrated achievement

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    Quote Originally Posted by Langbolt View Post
    Jerry....Like a 2003 CR250R ?




    not exactly. i dont believe late model cr250 has any adjustability or programing capabilities what so ever. unless theres some trick aftermarket parts available ? electrical isnt a bad method but with no way to alter its preset variables, i would just as soon have a mechanical system like the ktm
    to much power is almost enough

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    Quote Originally Posted by udontknowme View Post
    not exactly. i dont believe late model cr250 has any adjustability or programing capabilities what so ever. unless theres some trick aftermarket parts available ? electrical isnt a bad method but with no way to alter its preset variables, i would just as soon have a mechanical system like the ktm
    I do not know of anyone that makes a programmer for the CR250 ECU

    Power valves need adjustability because different engine packages (pipe, ports, carb, ignition) need the power valve to begin activation at different RPMs and move from fully closed to fully open over different RPM spans. The only power valve systems that I am aware of that offers this type of adjustability are the KTM mechanical and the electronic/laptop programmable systems.

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    Racer christph's Avatar
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    I think the rotax assembly will work with a CT cylinder. I talked with Allen at CT a few years ago about doing that conversion and he said it would work. You might have to do some machining so the exhaust passages meet up. You might call Allen and ask since it is his design, but I think I'm remembering our conversation correctly.
    1982 ATC 250R
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    1989 TRX 250R

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