As long as you're under 160-170psi of compression, you can run pump gas.
But it all depends on detonation (which should not occur with 93 gas and less than 160psi).
Here's how to find the right fuel.
First, keep in mind that the engine is likely to detonate only at top rpm (unless you compress really a lot).
So put some 93 fuel, warm the engine (bla bla), when ready, do a test, open wide. If the engine just runs as usual, you're good for 93 gas. If it detonates, let go th throttle, get back home, flush carbs and gas tank, and mix some race fuel, with a poor ratio (lots of standard fuel for very little race gas), then do the test again. Do this until you don't have any detonation. If you're not very far from running pure 93, then it could take just little race gas, and nost cost you an arm and a leg.
If my theory is wrong, please, someone say it. But if I got everything in the article from Kevin Cameron, this should be it.

 

Are you serious? 3500 for a pre 90 banshee?? That's unbelievable!! I got my 98 last summer for 4500$cdn (3000$us),and it was piped, tires brand new...etc. Duning rules I guess.

 

It depends if your carbs are moved (do you have carbs with the 400FMF kit?) or not. If the carb placement is changed, then you'll have a hard time fitting them with the airbox. One solution is to make your own airbox out of aluminium, silicone and pop-rivets. If the stock airbox can be kept, an Alba lid would be the minimum (the one that flows and keeps water out).

PS: you can shine your quad, even when trail riding (I do), just need to clean it often.

 

Loof on the FMF website...this thing looks awesome..i mean you get new cylinders, billet head with interchangeable domes. new intake, powervavle. and they use yz250 reed cages which solves the small intake problem of the banshee. If i had the money i would get it. besides you get the kit then you can sell your cylinders, head and carbs and make alittle of the money back. i just think this kit is real trick and is better than gettin a 420 kit or anyother kit.

 

Does anyone know of a place to order this besides FMF (website & phone). I called a couple of the mail order places, but they either don't care, wan't to charge full MSRP, or there distributor doesn't have them. I guess it seems like you should be able to buy this kit for less than MSRP from somewhere. Might have to wait till the new wears off alittle?

Charles

 

I don't think you guys really know how much better cylinders with power-valves are. You can have explosive low-end and mid -range power with good top-end. With the power valves, you can hog out the exhaust ports for great top-end, and not lose any of your low-end or mid-range power. I bet the cylinder come ported on the conservative side, so there probably will be more power to be had through porting. I don't think it would be the best set-up for dunes, but would be awesome for mx or trail(woods) riding.