I think the reason meatball would tell you that, is because in order to properly do a BBK on an AF05 Spree engine, takes ALOT of resources and several rare parts. It CAN be done with what is available to you, but the Spree is very picky because of that intake. As I outlined a couple pages ago, a person needs to put the focus on the intake/reed system, not the carb or air. This is where you will run into issues if not addressed. This is the part that will jack up the cost if not planned well.
I can say this definitively because I spent the entire summer examining the AF05 engine with a BBK on the dyno with my buddies (professional mechanics), and consulted several of the engineers at Polaris where I work.
My solution, of running 96:1 in the tank, retaining the pump and retaining the air box, WILL make it run within a decent range on your stoich air/fuel, which is what you want, but does NOT maximize the potential for the BBK.
If you do wanna push it further like I have accomplished (52mph wide open throttle till it runs out of gas), then better give the wife some divorce papers, because she's gonna really cuss when she sees what that will cost.
It's too bad the Kitaco intake has been discontinued. I e-mailed Kitaco last week about this, and what they had told me, was in order to produce the 410-1028000 intake, they needed a minimum order of 300 units.
I also contacted japan.webike and just received a response from them on it which said:
Code: Select all
Dear Eric
Thank you for your inquiry.
We will make an order to each manufacturer/distributor for each items
once we have received an order/quotation request from our customer.
We are sorry we cannot accept to have in stock your requested item in bulk.
We are sorry that we are not able to grant your request.
Please feel free to ask us if you have any other questions.
We are looking forward to serving you.
Best regards,
Webike staff
So anyway, that leaves the problem of using a better intake then stock on a Spree for the BBK. Only option available now, is the SB50 intake and reeds. Or... port the Spree intake.
It's an awful lot of money and an awful lot of trouble to go through just to hit 40mph. Would be nice if someone just made a simple CNC adapter for the intake to put a Dio carb/reeds on it or something.
The BBK itself is awesome, a Polini carb is pretty bad to the bone, but having both won't help the intake problem.
Or, to explain it in "STONER" terms. Imagine the BBK/Cylinder are your lungs, imagine the carb is a big huge bowl packed with weed... biggest bowl you can find.. now imagine the intake on the Spree, is your screen... the problem is... your screen is too clogged, so it doesn't matter hard hard you suck with the lungs, or how huge that bowl is, ain't only a little bit is getting through, and guess what... now you're gonna cough.
Hopefully that analogy explains it, and also explains a bit why I will tell you that the 3 holes you drilled in your airbox, is too much air. You want that back pressure from the air box. Cover up those 2 holes that are right beside each other, and only use the one closest to the normal inlet. If that makes it dog a bit, then uncover 1 more. 3-1" holes, is way too much air.