Hey everyone, my first thread here but I have been reading on the site for a while.
I recently bought a 2001 ls650 and I have been trying to learn as much as I can about it.
I did some changes to it already like swapping out the petcock for the raptor, changing the air filter for a k&n drop in, and Richening the idle mixture a bit to stop backfire.
However, I noticed that when I let up on the gas to shift or slow down, the engine rpm drops very low. In some cases, mainly 1st the 2nd gear and 5th to 4th gear, the engine will actually shut off.
So far I turned the idle speed up a bit which seemed to help but it definitely up higher than normal. My guess is that I need to rejet after I changed the petcock and filter but I wanted to be sure.
Thanks for your help.

The Number One LAW, not rule, Maintain an idle above 1,000.. If youre trying to idle low to enjoy that Thump,, the head will die, due to lack of oil on the cam journals. So, Get the idle at 1,000 ish, tune accordingly,, Theres a TEV or some such wonkoid thing on the right side of the carb, Throttle enrichment valve, I wanna say.. It can be dirty or need the spring tension "adjusted".. Theres some guys here whove Been there,, so,, You hang in here and one or 2 who KNOW fo Sho will be along..

If you achieve the best idle with the idle mixture screw somewhere between 1.5 - 2.5 turns out....your pilot jet size is good.  If you get close to 3 then the pilot jet is too small, if you can almost turn the screw all the way in...the pilot jet is too large.

If when you begin to apply some throttle, and you get a hesitation or uneven acceleration up to about 1/8th-1/4 throttle....and it accelerates well when you give it 1/2 or more throttle....you need to do the white spacer mod and remove the white spacer and install 3 washers.  If the hesitation is better but still noticeable, then remove 1 washer so that you have 2 washers on the needle.