2009 Dragon mid range flutter

[alberta chad]

Okay everyone. Need a little help. Good friend of mine has a 2009 800 Dragon 154". It has about 1600 miles or so on it. He had the update done when relatively new of dual ring Pistons and new head. He is having a mid range flutter he said. At around 6500 rpm. If below or above that, no problem, things runs good. He said it almost feels like it is detonating partially, said it spits and sputters. Getting about 110 psi in each piston for compression.

We need some ideas to look for to see if we can figure it out.

Thanks.


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[Vance Matheson]

sure sounds like power valves. probably sticking or a leak..

 

[alberta chad]

He said he was going to check them but had cleaned them when this first started happening periodically last year.
Would reed valves do this? He was going to check them anyway. If so, Can they be cleaned, or just replaced?


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[Vance Matheson]

try bypassing the solenoid. pull the hose off and plug it. take it for a rip and see if the flutter goes away or changes. i would also take the valves and spark plugs out again. put a flash light in the spark plug hole and look and see if the pressure ports are clear. check the valves and bellows again.

Plugging them would be simular to the old ves setup.


not sue about the reeds, but im doubting it if they are stock. vforce reeds then maybe they like to chip

 

[alberta chad]

Will let him know to try. Thanks a bunch for the help.


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