Mikuni 33mm BSR & Boost.


This doesnt have much to do with inlines, But You guys know your carbs ;)

We are turbocharging a Yamaha Raptor 660-R

Its got Dual Mikuni 33mm BSR Carbs, and I am wondering if they are internally sealed or not.

I don't want to build a box ;)
perhaps this has been answered already but its in the same vein. I wanna know what carbs for the 250 are internally sealed for turbo use.?
not many. There are very few carburetors that are ready for boost right out of the box. unfortunately my library is a little unorganized at the moment and I cant seem to find what carbs are as close as possible to bolt on. A mikuni does sound like one of them though. Its not really the seals that need to be boost ready but the float needs to be solid, not hollow.
Right Snowdragon, So the Float Does not Collapse.

What I am Concerned about is if the bowls, venturis pre butterfly, ect are vented to atmospheric pressure. That would cause a pressure differntial which could cause problems.

But Like I said earlier, I am fairly certain all newer carbs are sealed due to Emissions reasons (venting raw gas is frowned upon)

But, I do not know if that applies for Off road Vehicles such as this.

If it comes down to it, we will try it and see. Worst thing that could happen is pressureized air comes blasting outsomeplace it isnt supposed too ;)
8) other than jetting, to make a carb ready for a blowthrough install you either need to modify the base plates and vents, or use the same approach that paxton did and seal the carb in a box. for a draw through set up you really only need to rejet the carb. also as stated the floats on the blow through setup need to be solid to prevent collapse and you need to run higher fuel pressure to compensate for the boost pressure.
Yes I realize that, Wich is why I am asking, Does anyone have knowledge of all the vents on Said carbs ;)

Drawthrough is out of the question as we are going intercooled.
my 90 cr250 have hoses that came off the carb and went south. all bike carbs I have seen are like that. that way if it floods it will still run and just leak teh excess fuel instead of dieing. check the carb for some nipples on the sides.

hm. Just a thought, why not Not use carbs, but instead run a TBI or some other injection system, with a mechanical secondary that has a synchronised opening system with the primary barrel? That way you'll be able to MegaSquirt it, etc etc... :)
Forget Megasquirt - haha. GM-ECM's are the way to go currently.

As far as injecting the Quad, Computer's dont like Water and Quads see alot of that.

Secondly, the EFI won't make more peak power than a properly jetted Carb setup and You really arent to worried about driveability on the Quad, haha.

Its normally WOT or Not ;)