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9.9hp Yamaha 2 Stroke de-restrciting

C

confounded

New member
I have recently acquired a 9.9hp 2005 Yamaha 2 stroke. I have been informed it is relatively easy to de-restrict to achieve the performance of the 15hp 2 stroke.

Is there a good guide somewhere on what to do? Also is it something that would be recommended by anyone who has experience in doing it?
 
I have recently received this information from the guy I purchased it from.

"It's a simple restrictor plate which needs removed. Its that brass plate behind the carb. It's held on with 2 bolts and restricts the fuel/air mix going into the block of the motor. By removing it you allow a larger rate through the reed plate (which also gets changed - see blow) which gets burnt creating higher PSI per compression, giving the extra HP.

£30 for a reed valve which sits behind the restrictor place as that would require changing too from the existing 4 reed to a 6 reed type to cope with the extra fuel flow. Again a simple job and easily available part from Yamaha."

It all sounds pretty easy, is it really this simple or do more changes need to be made to ensure everything is correctly balanced for the extra power? Also is a change of prop needed?
 
Can any one help, I am keen to make the changes suggested above but do not want to get caught out with the "little knowledge can be a dangerous thing" situation.
 
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