Essentially all that is done is to replace the restricted air inlet tube with a sheet of plastic that provides the isolation between unfiltered and filtered air. By enlarging the front plate inlet air restrictions are reduced. The net is an apparent performance improvement from a standing start all the way through the speed range. High speed cruising (70+) is easily accomplished with less throttle applied.
My initial observation with my 400 are that WOT speeds from a standing start gained 5-7 MPH in about 100 yds. The same with mid-range acceleration. I am currently riding without the modification and it is back to being somewhat sluggishin the mid-range and very little acceleration over 65 MPH.
I have the plates available for sale seperately or you can send me your airbox and I will modify it for you.
Right now the plates cost $30.00 each. This price will change depending on order size. The plastic is not the expense! It is the setup costs. The plates are cut on a CNC waterjet machine. The setup costs are somewhat variable but will be in the range of $200 per setup. I had eight peices made for the initial run and have three currently available.
If you want me to make the mod for you the cost will be $50.00 for the plate and the mod. I think I deserve something for my time since it takes about two to three hours to complete.
I don't know yet what shipping will cost but I will work that out yet this week.
One thing I do know is that this mod will work on all Master 4/500 cc engine CVT setups. So I guess that would include Piaggio's and the rest that use this engine/tranny combo.
Well, what do you guys think? Interested?
This is what we start with.
The inside of the airbox. Remove the rubber tube and clamp.
The air tube and clamp can be discarded.
Plastic is removed from the front plate restricting airflow into the filter.
CAUTION: do not remove any more plastic from the top of the restrictor plate that is required to remove the top of the fitting for the rubber tube.
This is the isolator plate that seperates filtered from unfiltered air.
The plate is secured with glue and left to cure for 24 hours.
When the job is done, this is what it looks like from the outside.