Pilot jets or Main jets

[btxs650]

Have installed pods and went up to 142.5 main jets and up one size on pilot jets. The bike runs a lot better but there is a small lag when you first pop the throttle then it takes off. Do I need to go up another size on the main jets or pilot jets? Or could it be that I didn't adjust the air screws?

 

[ironwill]

From the carb guide: If you've created a flat spot just off idle by lowering your needle , you'll need to increase
the pilot jet size. Any pilot jet change needs to be followed by a re-adjustment of your
mix screw. You've just richened the idle fuel mix so the mix screw usually needs to be
turned in (leaned) slightly to compensate. The 34s also have an air jet you can change.
This feeds air to the pilot jet to create the fuel mix. Along with increasing the pilot jet
size, you can decrease this air jet to richen your idle mix on the 34s. The 38s have an
air jet as well, but it's fixed and can't be changed, so it doesn't enter the tuning equation
with them. One size up on the pilots is the norm but you may need more. Re-set your
mix screws and test for the flat spot off idle. In 2nd or 3rd gear, slow down to near
stalling then grab a big handful of throttle. You don't need absolute full throttle like for
the main jet tests, just a good sized handful. This will reveal if you've cured your flat spot
and, if you've gone up several sizes and get some stumbling, that you've gone too big
on the pilot jet size.

http://www.amckayltd.com/carbguide.pdf

 

[gentlemanjim]

I went 137.5 main and 47.5 pilot, XS Johns needles works great no flat spots, crisp throttle response.

 

[Inked Monkey]

I'm running the 142.5 mains and up 2 on the pilots. I've got pod filters and drag pipes.