...consumption??

I was just wondering if the needles in the slides make a big difference for fuel consumption, when i bought these 40mm carbs they have the 7DFY1. I am supposed to run 7DH2?

Would this make a difference in performance and fuel economy?? thanks, neil.

if you drop the needles yes better mileage. you will lean out your mid range though.

Possibly.The different needles will have different diameters or shapes to allow more or less fuel(depending on the needle) at a specific range in the throttle opening.I would definetly try the right ones for your engine.I've had to drop the needles on two sleds.Both were 583s and both were first year builds in new chassis's(94 STX & 97 Formula 583 with 38s).Both were gas guzzling pigs that fouled plugs and were totally transformed just by dropping the needle one notch.If the sled is working well with the factory setup dropping the needles could lean it out too much and cause a burn down.

the needle that is in it is not the factory , its a 7DFY1. In my shop manual for a '88 PLus 521 engine with 40mm carbs i should be running a 7DH2.

The sled is running ritch and has no bottom end and is guzzling SO much gas.

DO you think this would help me?

Yes.

hey A C man how do u like your STX LT?