[Photos updated 11-22-2010]
Now for the cleaning.
You may want to clean only the pilot and main jets.
You can. And if the carb isn't too dirty this may be all that is necessary.
However there are several internal air and fuel passageways that also need to be cleaned.
You can spray carb cleaner through them (use eye protection).
The best way (IMO) to clean the carb body and the internal passageways is to use an ultrasonic cleaner.
I used plain tap water along with a few ounces of Dawn dish washing liquid.
If you are going to use a carb cleaning spray or solution, wear gloves and eye protection, and use in a well ventilated space.
It is nasty stuff. It can blind you, and be absorbed through your skin.
It can also dissolve rubber parts. Do Not use it on gaskets, o-rings or the slide diaphram.
If you don't have access to an ultrasonic cleaner, you can use these
In any case, in order to completely clean the carb, all the internal parts should be removed before soaking the carb.
You can try soaking the carb without removing the internal parts, but there is no guarantee that the part that is causing the problem will be cleaned.
Remove the float bowl. Then remove the gasket and the plastic splash ring at the bottom of the bowl, and used cotton swabs and an old toothbrush with the carb cleaner to clean the bowl.
When the bowl is clean:
Remove the main jet (7mm socket) and the main jet holder (8mm socket)
There is also the main nozzle (main jet needle) above the main jet holder.
The main nozzle falls out easily. Don't lose it. It will cost you $25. US.
Remove the pilot jet (small flat blade screwdriver).
Clean the main jet, main jet holder, main nozzle, and the pilot jet.
I soaked them in carb cleaner, and used a guitar string (high E) to clean the holes. You can also use a jet cleaning wire set. The wire set is $15. The guitar string is $1. at your local music store.
Before removing the pilot screw gently turn the screw clockwise, counting the turns, until it seats.
Remember how many turns.... 2.5 turns is an average setting.
Remove the pilot screw. Make sure to remove the small o-ring.
It can stick inside the pilot screw passageway.
Now to remove the carb float and float valve assembly.....BE CAREFUL.
THE POSTS THAT HOLD THE FLOAT IN PLACE ARE FRAGILE.
THEY CAN BE EASILY BROKEN....THEN MOST LIKELY YOU WILL BE PURCHASING A NEW CARB.
The float pin is pressed into place.
After removing the retaining screw, I used a pair of slip-joint pliers and a small finish nail to push the pin out.
Here are the float and float needle removed:
Removing the float needle seat can also be difficult.
I used a needle nose pliers to grab the edge of the seat and carefully wiggle it out.
I have also damaged a stuck valve seat beyond repair and had to purchase a new one.
A bad o-ring on the valve seat is one of the main causes of a leaking carb. It is a good idea to replace it.
Next remove the parts from the top of the carb (vacuum chamber):
Then remove the coaster circuit parts on the side of the carb, and the choke assembly:
Here are all the parts you should have:
Now the carb parts can be cleaned individually, and the carb body soaked.
I used a dip of straight Pinesol...left it in overnight.
You can also use Simple Green, Yamaha Carb Cleaner, or the more toxic Berryman Carb cleaner.
After dipping the carb body and parts, rinse in clean water, and let dry.
And as they say in the BMW manuals, assembly is just the reverse of disassembly.
When you have the carb reinstalled in the bike, you will need to go through the "carb tuning" procedure for best performance.
There is a tuning "how to" in the Technical Write-Ups.
If you get stuck or are having difficulty, please post your questions in the "Tech" section of the TW 200 Forum.