Does this sound reasonable?

[bandanshee]

Just finished some more porting on my cylinders and got it back together and rode it yesterday. My mods are in my sig. With these mods, I am running a 320 main and stock needle/pilot at about 75F and about 1700 feet. This just sounds lean to me. It ran fast as hell, and the plugs tell me that I am jetted about right.

The only problem is a "flat" spot for about 500 rpm in the low-mid range where it seems to sputter and hesitate. This is right before powerband- it starts picking up at the low rpm fairly well, then hits this spot where it hesistates and sputters for a few seconds until it hits powerband then it takes off like crazy.

Should I theoretically be running a fatter main than a 320? Also, I am wondering how I could work on the flat-spot problem. Maybe the stock reeds have something to do with it?

[dajogejr]

Not neccesarily....

Sometimes porting actually like a smaller jet because is can pull just as much fuel/air as a non-ported motor, more efficiently....

 

Stock needles in the stock carbs have a known lean spot in the middle...and porting your motor may have exposed this more.

 

Dynojet (toomey) needles AND Vito's needls are longer yet skinnier to prevent this lean spot.

Needles are 3 times as much as any main or pilot jet. Magic used to have the Toomey Jet kit for 29.99 on clearance....no longer. I think last time I talked to Toomey, they wanted 17 bucks EACH for the needles...they didn't believe me when I told them I could get the kit from Magic for cheaper....

 

See if you can find some Dynojet needles or Vito's needles on ebay...if not, go direct to the manufacturer....

 

You MIGHT be able to tune this out with a combination of the following, pilot jet, air screw and moving the clip on the needle....

 

Good luck!!