gusto

BansheeHP (Bill from Driveline) has done lots of experimenting with his set up, he added boost ports, 70mm bores, dyno'd lots of pipes, etc. Might be worth an email on here. Good luck with the build and post pics of the setup

Sounds like your building something special. I had Cam do my engines, the last was a 421 and i had the same concerns. We went with 28s and a desert tank for mileage, its better on gas but i cant tell you by how much because its the only carbs ive ever used on it and its been riden sparingly. I just ordered 33s for it due to its hard to tune between pipes with these carbs. I am currently building another 421 serval and i am not convinced i should. I kind of toying with the idea of a 347 or 358 cub or a 392 serval or driveline setup. A guy out here has a 392 DL set up by the guy at DL and its real impressive. The guys at Driveline would do my next build over anyone else if i was using their cylinders, they have done some experimenting and i thought the results were excellent.

Desert tank makes a big difference. What pipes are you running? Im asking because there is hp to find there, Shearers would make a nice difference on that engine. What Claude said, porting is going to kill your gas mileage.

Also check the Toomey website for jetting advice, there’s great info

Yep, I’d be surprised if your stock stroke stock cylinder main jet is over 300. If you have fmf fattys they like a bigger pilot like a 30, but I would def buy 27.5 also. Set your slide mid way and adjust from there. report back

270-290 main 30 pilot obviously your main is your problem

make your own, its simple

I’d never buy a plus 4 again, plus 2 max

If your drag racing the 39s General purpose the 35s

Where did the Shearers go and do you like the CPIs better?

you will need domes

+4 is safe.

SLP

100% depends on where and how you ride. If your strictly trails or track I’d use SLP. I had PCs on my 4 mil and they pulled real hard in the mid range. I wish I would have kept them. For a do everything pipe I like PCs a lot

Those a great trail pipes. They usually require a bigger pilot jet like. Another option is port your cylinders

Is your bottom end shot? If not true and weld your stock crank, they’re very stout. the driveline top end for 800 is unbeatable. You would be at 392 cc with the stock crank. What pipes and reeds do you have?

And you’ll need gaskets at the reed cages. While your doing that check your reeds, if they’re chipped or showing light through you’ll need new ones. build or buy a leak down tester. the jet sizes are written on the bottoms of the jets. So you have stock exhaust pipes?

He’s asking about the tube that connects both carbs. If your missing that it won’t run. id leak down your motor. what mods and what size jets?

Banshee prices in Canada has doubled in three years. Personally I wouldn’t because the banshee will be worth more.

No expert with those carbs, if your close on the jetting only adjust the slide at this point. That will tell you if your going to need more or less jetting

Vforce make more power, I’ve heard the Boyensen last longer (have no personal experience) fmfbpowercores will be great trail pipes, if your building this for open road but a different pipe

Both CP and DriveLine offer a 68 mm bore (392) CP also has their super cub and super serval in 72 mm for 440 cc true and weld your stock crank

What’s it doing?

Might be LSR, they usually have a star cut in the a arms. LSR will sell what you need, basically all a arm makers will sell what you need. Alba is definitely the cheaper option, you capfuls try saying BansheeHQ member for a discount. Check sponsor list. i might be interested in those a arms also I’d you do not use them

oh how i wish i lived closer. Id snap this up.