I bought 3 #4 washers and I've tried all but still get the washer sitting on the outside of the legs of the "white plastic piece". Surely that can't be right. Shouldn't it slide all the way with the needle? I wish I could post pictures but I'm not at 15 posts...
Are you operating at altitude?
If so, I agree with pdwestman; doubt shimming the needle's a good idea, as the procedure FUEL-ENRICHENS
the mixture in mid-to-wide-open throttle range; unlikely to help air/fuel ratio at altitude. Why would you want to fuel-enrich your mixture beyond stock air/fuel ratio when operating at altitude? You'd want the REVERSE, right?
But, should you ever wish to shim the slide: A MODEST PROPOSAL: View the FIRST video on this thread: http://www.klrforum.com/how-tos-tech...-overhaul.html
. At about 3:30 and following, you'll see how the carburetor, slide, etc., are assembled; then . . . at around 4:25, you'll see ACTUAL 22-Cent Mod washers EXTRACTED from the carburetor!
You will notice, no interference exists between the white plastic "fingers" of the spring retainer, because . . . the washers fit flat in the mixing chamber; the washers only see the flat side of the white spring retainer, NOT the fingers.
My perception/interpretation . . . YMMV!
Regardless, don't think you need no stinkin' # 4 washers at altitude, for reasons specified.
And, I'll reiterate the oft-repeated info . . . drilling the slide only improves throttle response; HAS NOTHING TO DO WITH AIR/FUEL MIXTURE.