I have a guy who can produce you stampings. He was gonna start new stampings for David at Rocket as the original dies were Mia after sitting in storage. If you are SERIOUS, I will make some calls. PM me and Let me know and I can try to get you in touch. (He currently makes stuff for magnum)
Johnny number 5 need in...put!
Man, at first I was thinking round tube and HD? But fuck, that sleeve is a bitchin idea. Take that thing out to your track with a go pro aimed at it and beat it up and see how much difference it really makes.
Your budget puts you right on par with a killer 4 mil build. Tear it down, make a list of any of the misc OEM clips and washers and adjusters as order that stuff from fast. Fast can also set you up a nice 4mil crank for a great price as well. Send the jugs to get ported for your style of riding and have domes done as well. Your builder will guide you toward which pipes and stuff to get as they will tell what will work best with that particular portwork.
Find a nice used front suspension set up (a-arms and shocks)
Rebuild rear shock for your weight and style
Used axle maybe?
Ez pull clutch lever
Reeds
Cut and chambered stock head or cool head
Timing plate at +4
Exhaust
Pod filters
Tors delete
Parking brake delete
Shifting mods
Welded crank
As motor size goes up the stinger diameter definitely corresponds. I've seen a lot of guys who hop their kids eatons and vipers. The faster ones are guys finding CR 80 exhausts from FMF or Pro Circuit and cutting them up to work on the kids quads.
I've been there! After several float adjustments I almost gave up. I would have to say check the little brass tube in the bowl. Especially if you have Billit bowls. They can tend to get bent downward when people are installing the bowls back on in a hurry. Give it a little vertical adjustment and I bet it helps.
Stay away from big bore kits for stock jugs. Get the 4mm crank and port the cylinders. My last motor was a big bore in stock jugs. What a nightmare to keep it sealed up past 68 mm if you wanna run any compression and timing. My current motor is 4mm ported stock cylinders and it is far ahead of what my big bore was capable of doing. The only difference is my new motor is 40/50 CC's smaller so there was a bit of a displacement advantage which helped lugging it out of a turn or up a hill. But that's fixable with a bit of clutching. If you want more then the stroked ported stock cyls can give ya, then get a new monoblock type of cylinder and move up.