45 pilot jet

Just wondering if the 45 would be too rich in a 400 with a yosh slip on,k&n filter, no choke. I know everyone says go 42 but my dealer insisted on the fact that there is no 42 so i ordered the 45
any info or opinions appreciated

[PsychoDave]

I RUN A 45 AND HAVE NEVER HAD A PROBLEM

how many turns out on the fuel screw? just so i have a starting point. and how many turns out is stock do ya know?

[PsychoDave]

I TURNED IT OUT TIL IT STARTED TO RUN A BIT ROUGH THEN TURNED IT BACK IN A 1/4 TO A 1/2 TURN.

THE STOCK SETTING I BELIEVE IS 2 1/2 TURNS OUT

thanks guys, when your bike sputters and pops when you're deaccelerating does that mean your pilot is lean??

[froggieboi]

If I'm not mistaken backfiring on deceleration means your main is to lean. Someone correct me if I'm wrong.

[PsychoDave]

IT COULD ALSO MEAN THE LITTLE VACCUME ON THE SIDE OF YOUR CARB IS LEAKING......THE LITTLE VACCUME IS THERE TO CUT OFF AIR ON DECELLERATION( MAKE A RICH FUEL MIXTURE) TO PREVENT BACKFIRING. BUT THEN AGAIN YOU COULD BE JETTED TOO RICH ON THE MAIN LIKE froggieboi SAID.

[Wheelie]

Backfiring on deceleration often means one of two things--exhaust leak or lean on the pilot/slow circuit. You can help the problem by going to a larger main jet, but then another problem is created: an excessive rich main jet to compensate for the still lean pilot jet---performance suffers throughout the powerband.

On a modded bike that backfires, step the pilot jet up one size before increasing the size of the main jet. Chances are, the backfire will go away.

Good Luck!!