on my 87 lt250r i went from the stock 34mm flatslide to a 38mm round slide. i had the stock carb jetted 280 main and 40 pilot. how does going up in carb size change the jetting. i have the new carb jetted 260 main and 35 pilot, it won't run unless the air screw is only 1/2 turn out but then it still bogs bad on takeoff. should i go leaner or richer on the pilot?

rick

 

I WOULD TRY GOING BIGGER ON THE PILOT JET FIRST, IF IT GET WORSE THEN TRY LOWERING IT, BUT USUALLY WHEN THE AIR SCREW NEEDS TO BE CLOSED THAT FAR YOU ARE NOT GETTING ENOUGH GAS. YOU DIDN'T MENTION WHAT TYPE OF CARB BUT I AM GUESSING BY THE JET SIZES YOU ARE REFERING TO THAT IT IS A MIKUNI. IF YOUR BOGG IS IN THE MID RANGE THEN MAKE SURE TO ADJUST YOUR NEEDLE AND KEEP CHECKING THE PLUG. MAKE SURE IT STAYS BROWN, WHITE IS TO LEAN AND BLACK OR FOULED PLUGS ARE TO RICH. BY THE WAY CHECK OUT INSTALLING A U.F.O. ON THE ROUND SLIDE CARB. IT IS AN AIRFOIL THAT ADDS 1 HORSEPOWER FOR EVERY 100 CC AND MAKES THE CARB ATOMIZE LIKE A FLAT SLIDE CARB, PLUS IT IS CHEAP AROUND 30 BUCKS.