T300 Mikuni Carburettor Maintenance
	Dismantling
Home Tools Cleaning Inspection Parts Reassembling Balancing Jetting		Start with the lower components that are accessed via the float bowls
		For cylinder 1 (only) it will first be necessary to remove the idle adjuster bracket
		This will then enable you to remove the two Phillips screws holding the float bowl on to the main housing
		Remove the rubber sealing gasket from the float bowl for later cleaning and inspection
		Next, carefully remove the float assembly. It is firmly seated in place by means of two sealing O-rings. Lever the assembly gently and evenly from points close to both sealing points to detach it from the main housing
		The float assembly can then be disassembled into its components parts. Carefully and gently prise the outer frame plates slightly apart, just enough to pull the inner float frame pins out of their pivot holes
		With the two float frames separated, you will now be able to extract the float spring valve from its seating
		After removing the two sealing O-rings from the outer float frame legs, you should have all the separated float assembly components as shown here
		With the float assembly removed, you can then access the pilot jet as shown here. Carefully unscrew and remove the brass pilot jet using a small slotted screwdriver
		This is what the pilot jet looks like once removed. Its size will be stamped on the side of its shaft. It is good practice to keep a record of all jet sizes used for future tuning reference
		Next to be removed is the main jet as indicated here. Use a larger slotted screwdriver to carefully unscrew and remove the main jet
		Once removed, this is what the main jet looks like. Its size will be stamped on the top of its head. Keep a record of this jet size too
		The pilot air screw assembly is next to be removed. IMPORTANT: The exact adjustment of this screw needs to be ascertained BEFORE its removal.
	The adjustment position is measured by how many “turns out” the pilot air screw is from when it is fully wound into its CLOSED position. To assess its current adjustment, slowly and carefully SCREW IN the pilot air screw and COUNT the number of turns (including any fraction of complete revolutions) until it JUST closes. This is best done in half-turn increments. STOP as soon as you feel it close. DO NOT OVERTIGHTEN as this will damage the carburettor. Once you have taken this measurement and recorded it, unscrew the pilot air screw all the way out and remove it from the housing
		If the pilot air screw assembly comes out as a complete unit, it should look like this. Sometimes, some of its components can remain inside the housing, in which case you will need to carefully use a small hook to retrieve any missing parts
		Once you have completely removed the pilot air screw assembly, you should have all these component parts
		You can now turn your attention to the components parts accessed from the top of the carburettor
		Remove the two Phillips screws securing the carburettor top cover, and carefully lift it off of the main housing
		Remove the diaphragm return spring from the carburettor slide
		With a small hook, retrieve the vacuum take-off O-ring seal, then remove the complete diaphragm and slide assembly from the main housing
		This is what the complete diaphragm and slide assembly should look like, along with the diaphragm return spring and vacuum take-off O-ring seal
		Push the jet needle up and out of the slide assembly, along with its spacers. Shown here is the needle position clip. Before the clip is removed, its position should be recorded along with the jet size information for future reference.
	There are FIVE clip positions, and they are enumerated from top to bottom. In the picture shown above, the clip is in position FOUR, as it is in the fourth slot down from the top
		Carefully remove the diaphragm from the slide body. Shown here are all the parts that make up the slide assembly
		Next to be removed from the main housing is the plastic slide guide shown here
		The bottom of the slide guide is anchored by the needle jet. If the assembly cannot be easily prised out by hand, from underneath the carburettor housing place a small slotted screwdriver up inside the main jet aperture and gently tap it loose.
		Once fully dismantled, these are the component parts of the slide guide assembly you should have
		The final assembly to remove from the carburettor housing is the choke needle as shown here
		But before you can proceed, you will need to remove the choke actuator bar which links the choke needles of all three of the carburettors
		The choke actuator bar is secured by two plastic clip inserts that slide into their restraining lugs
		Use a slotted screwdriver to push both of these plastic clips laterally out of their lugs to release the actuator bar. It should then be able to be lifted away from the carburettor housing
		The choke needle assembly is released by pressing in towards its centre the two black plastic retaining lugs at the rear of the unit in the housing. This is what your removed assembly should look like
		Repeat the above steps for carburettors two and three, and store their components in separate storage boxes as illustrated here
Back to Top	As a final check, you should have ALL the above group of components for EACH of your carburettors in their storage box