Like allready said , if the porting dosnt match the pipe design, you may never get all the flat spots worked out.
I would first do the 1.8 to 2.0 timing and for grins, if you have a set of stock metal yamaha reeds, put those in and do your main jets from there. Leave the stock needles in the middle position for the time being.
I also would just run premium pump gas if your compression is below 140 PSI.
And yes, the intake manifold crossover with the boost bottle helps smooth out the notorious mid RPM flat spot somewhat.
Ever Onward screwed with this post 07-07-2012 at 06:08 AM
Reason: forgot stuff