Hi funonemax. I'll try to answer your question as well as I can.
From what you explain on the long warm-up symptoms, it sounds like the PZ27 carb is set up out of the factory like most of them. Lean. If you can access the idle mixture screw, try resetting that first. I got 1 3/4 turns out and adjust from there. Depending on your elevation, you may need rejetting. I've had good luck with the Kehin copies but I'm trying the Mikuni this time just because....
Regarding the suspension, the shocks do suck but I adjusted mine to the lowest (softest) settings front and rear last night and it actually bounces now. Try that first. No fancy wrench needed. Twist the lower spring seats with a pair of channel locks.
The spacers I ordered was from a ballpark measurement I took so hopefully they'll work. I ordered these 4/110 2" spacers. If they don't fit, I'll remeasure when it's not 27' in my garage. I'll keep you posted after I receive them.
http://www.amazon.com/Factory-Spec-F...+wheel+spacers
Of the China quads, these are about as tall of tires they come with. Regarding a twist throttle, Mrs 2LZ would love one on the 150 ATV I'm looking at for her. Her Jetski had a thumb throttle and she hated it. I'd like to hear from someone who did the conversion.
The motor is probably the 167FMM. It's most likely a 229/230. My tank had a 250 sticker on it, the website says a 200cc and the frame tag says 150! LOL! Keep fresh oil in that motor and it will give you years of good service.
Looks like a ton of fun in your pics! Thanks for posting!