hey guys, here's the scoop:

my buddy has an '04 banshee with no motorwork. Has T-5 pipes and K&N Air Filter.
Here's the problem. He just bought a set of V-Force reeds and installed them earlier today. We go to fire the bike up and nuthin. Kick, kick, kick, kick, dead as a door-nail.
I hop on it and first kick it fired up but runs like it has a freakin 400 jet in it. No power band, no nuthin. I told him it was his needles so he moved the needles to the center notch in the carb. slide.

The jet he has in is a 280, which is normal for T-5 pipes and K&N. He rode it just to see what it would do and he cant hit the powerband until 4th gear. That kinda stumps me, cuz if it hits the powerband in 4th then it should hit the power band in all the gears.

And once the stock reeds are put back in, it fires right up. Any ideas????

Oh and another problem is the idle screws he just recieved. The carbs were drilled and all. Looks normal. But he can screw the idle screws all the way in and it doesnt raise or lower the slide in the carb..... any ideas on that as well??

thx guys.........~Ryan

I have seen the reeds put in upside down before....maybe you have a huge air leak in the carbs as well.....

Don't think so Had. If he had an air leak, it would cause it to live a spectacular but very short life as the leak would lean out the mix.


Are you sure you are turning the idle and not the air screws?

There is no reason I can think of that the bike would wait till fourth gear to hit the powerband. Is his parking brake on? That activates the rev limiter. Grasping at straws here.

Maybe a malfunctioning tors??????? Sounds like what it would do if the parking brake were on..... Keep it from reving high enought to catch the powerband........

YFZ 350 Banshee's are sensitive to "timing" the carbs so they lift the slides at the same time. Pull the air cleaner and ensure this is happening.

Also, my experience with changing intake tracts and reeds from stock opens up a can of worms for jetting. In the quest for throttle response desired by most Banshee dune users, there is many "tricks" provided by the aftermarket. Boost bottles utilize an old idea used by Yamaha on YZ and IT bikes. Reed spacers and some aftermarket reeds give a small gain on the throttle response problem.

Ultimately a power valve cylinder provides the best of both worlds. Good low-end power and great top-end. Perhaps this is why Yamaha manufactured the RZ 350 with this set up. In the end though, cost considerations likely factored in to why Yamaha left this off the Banshee.

Most I've spoke to indicate the Boysen Rad valve and the Delta Force set-up on a Banshee involves leaner jetting than expected. But here, with T-5's - more of a high rev type pipe that demands more main jet for power - I'm thinking that you have a complex jetting session ahead of you to get this thing to run right.

I suggest a plug check at 1/8, 1/4, 1/2, 3/4, and wide-open throttle for about a mile to determine your jetting problem. The spark plug tells the whole story.

Plugs can only show what the main jet is doing. 1/8 throttle is pilot jet which cannot be read by the plug. The needle controls where the air screw leaves off till about 3/4 throttle. That's when the main kicks in and you can read it off the base of the ceramic, not the nose of the plug.