HiPerf2000

iTrader: (2)

There are alot of great motor techs on this board, and i was hoping to find someone who is experienced in Two stroke carburation. I've been to ATV boards, but the replies are slow there compared to our board.

I've got a 2000 Banshee that i just rebuilt the top end (stock bore). Had it out and ran good. I decided to put FMF Knarly pipes on it, and jetted the carbs (stock 26mm Mikuni) to FMF's recommendations - 260m and 30p. I put it all back together and now is backfiring/poping when trying to bring up the Rpms. Once past this range the motor runs great. So i would think i am lean on the pilot circuit (i open the choke half way and i can throttle up much better). The only other mods are a boost bottle and K&N filter. I am using the stock airbox with the snorkle removed.

Someone told me i may have the slides in backwards. When i reassembled the carb(s) the slide had a grove that had to mate with a locater (set screw) comming in through the bore of the carb. So they can only go in one way right?? And yes i have the little hose that connects both carbs connected.

Anyone have any ideas?? i don't think i should have to go above 30 in the pilot...I've talked to other people who never changed thier pilot when installing pipes (left it at stock 25). I may pull the carbs off and clean them again...maybe i got dirt in the pilots???

I want to go riding this weekend

mxz800

when i built my quadracer years ago i would make a run down the road at say 1/8 throttle kill the motor check the plug. i would do this with 1/8 1/4 1/2 3/4 full i would compare all my readings and go from there. have you adjusted air idle screw? you may need to move the clip on the needle a little. first you need to determine if rich or lean condition. keep us posted

HiPerf2000

iTrader: (2)

I've turned both the air mix screws out two more full turns (now at 4 turns total).....still running like chit. It has to be a lean condition if it stops backfiring/poping when i close the choke half way...You would think anyway???

CheckmateF1

Hi-Perf, Did FMF say anything about lowering the needle clip position? That's 1st thing I would do. Start with one position lower. See how it runs.

Air mixture screws need to go in to richen the mix don't they? i.e. run the screw in to lessen incoming air.

Eric

HiPerf2000

iTrader: (2)

FMF gave these jet sizes based upon the needle being in the stock position. Is the needle easy to move -- just taking off a clip and moving the needle down a notch?? Wouldn't a downward needle movement reduce fuel flow??

CheckmateF1

Move the "clip" down to "raise" the needle. It's pretty easy. Pull the slide out and the needle will come out thru the top of the slide. Move the clip and reinstall.

Eric(former TRX250R guru)

hp500efi

Checkmate is right on.

Lower the "C" clip on the needle and that will raise the needle thus allowing more fuel into the carb at idle and 1/8-1/4 throttle. Try lowering the clip ONE notch and test. If a little better but still not right, lower clip ONE more position and give her hell. Make sure you check each carb on your ride so that each carb is the same. It is real easy to count the notches wrong on one carb and mis-position the other carb.

Pulling off the "C" clip is also a trick. What I do is take the needle with the clip attached and place it on a hard work surface. Position the needle down on the table with the "open part" of the "C" touching the table. Gently push down on the needle so that the needle pops out of the clip. If you try and pull the clip off the needle, guaranteed that it will go flying across the room not to be found. I also attach a needlenose pliers to the clip as I am pushing down on the needle just in case the bugger decides to go flying.

Good luck.

89 TRX250R man

NASTY HABIT

Make sure you didn't crack an intake boot..

HiPerf2000

iTrader: (2)

i am going out now to try to move the needles up (clip down)...i'll update you guys with my progress.

NASTY HABIT...the intake boots are rubber, but i'll spray them while running to see if i can find a leak.

thanks guys....any other ideas while i try this??

NASTY HABIT

That'll work.... 2000 they shouldn't be cracked but never know... if you try everything and are still having problems.. you may want to consider hitting the water instead...... or get a Honda kidding...i miss my 250R shoulda never sold it