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I was doing general preseason maintenance and thought I would snap some pics to help out those that would like to do minor cleaning and maintenance on their rack Mikunis. These came off my 2006 RMK 600, they are TM38 carbs.

1 remove airbox.jpg
First remove the airbox to access the carbs.

2 disconnecd choke.jpg
Disconnect the choke cable. There are 2 10mm nuts, loosen the one on the bottom until it is off the adjuster. Pull up on the adjuster until the adjuster clears the bracket. Rotate the end of the cable until the cable will clear the slot, slide the keeper end out.

3 disconnect throttle.jpg
Disconnect the throttle cable in a similar fashion

4 remove rack.jpg
Loosen the clamps and slide the carb bodies away from the carb adapters.

More coming
 

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Discussion Starter #2
Mikuni carbs (continued)

5 remove oil lines.jpg
Remove the oil lines. I like to plug them with something, golf tees stolen from my son works.

6 remove gas.jpg
Remove the gas line. If your gas shutoff works, you don't have to plug the line, but if the sled doesn't have a shutoff, plug this too. Make sure any electrical connections are free, you should have at least a TPS connector. To remove the connector, press in on the tab and gently pull. If it's not coming, you aren't pressing in the right spot.

airbox side.jpg engine side.jpg
Here's the carb rack airbox side and engine side

7 spray off exterior.jpg
Using an aerosol cleaner, spray off the exterior.
 

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Discussion Starter #3
8 remove water trap.jpg
With the outside of the carb clean, it's time to access the jets via the float bowl. The float bowl is held on mostly by the water trap hose/nut and partially by a small screw. Removing the water trap will allow access to change the main jet for tuning purposes or if other maintenance is not required.

9 remove small screw.jpg
Removing the small screw allows removal of the float bowl, exposing the three jets and the float assembly/inlet needle/seat. The float assembly is removed by removal of the two screws. There is a rubber O ring on the float. The float and O ring will require a bit of effort to remove, the O ring makes a good seal. Pry gently with a screwdriver around the base of the inlet and it should come out.

10 remove top.jpg
After removing the two screws on the top of the carbs, the top of the carb can be removed to allow access to the jet needle.

11 top of jet needle.jpg
This is the top of the needle. Note the position of the keeper, held by an allen screw.

12 loosen allen screw.jpg
Using a small allen screw, loosen but do NOT remove the screw. Loosening will allow you to move the keeper out of the way of the needle for easy removal.
 

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Discussion Starter #4 (Edited)
13 move keeper.jpg
Note the position of the keeper and access to the top of the jet needle. Under the E clip on the jet needle is a small neoprene washer, do not lose this. If you reinstall the jet needle without the washer, you can damage the needle jet and you will lower the jet needle, making your air/fuel leaner. That could be a problem.

14 remove needle.jpg
In this picture, the needle has been removed.

15 remove float.jpg
For general maintenance, these are the only parts I remove. After these parts are out, I put them into carb cleaner while I run carb cleaner through all the holes and orifices in the carb, paying particular attention to the inlet passages and to the needle jet. Make sure to point things away from you.

It's not a bad idea to remove the fuel screws from the carbs and clean those orifices as well. If you do, make sure you turn the screw in, counting the number of turns so that you can reinstall the fuel screw in the same manner in which it was removed.

On reinstallation of the choke cable, adjust the choke cable so that there is 1/8" free play from the bulkhead to the choke lever. When operating the choke lever, there should be a small amount of movement in the lever before the choke mechanism starts operating.

On reinstallation of the throttle cable, adjust the throttle so that there is about 1/16" of freeplay at the throttle lever. If the throttle lever is too loose or too tight, the throttle safety switches will keep the engine from starting or running.

The carb can be disassembled to allow changing of the slide, but that is not something that needs to be done yearly. Slides are plastic and do wear out over time. Sometimes adding a new slide to an old carb will give you a few years more usage from the carb.

Nothing too mysterious! Just a hint... if you have an IQ 600, getting to the oil pump is almost impossible! DO NOT PULL OFF ANY OIL LINES! It will take you forever to get them back on. Trust me on that!
 

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"Removing the small screw allows removal of the float bowl, exposing the three jets and the float assembly/inlet needle/seat. The float assembly is removed by removal of the two screws. "

I see in you later picture on top of the towel that you removed what looks like were these three jets. Is there any special tool or precaution that need to be taken to remove them or how to reinstall"
 

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Discussion Starter #6
For the main jet, I use an appropriate size metric nut driver (I forget the size). For the pilot jet, use a straight tipped screwdriver with a good edge. The pilot jet is in a tube and can sometimes be pretty stubborn. A rounded screwdriver tip can really mess up the jet. For the starter jet, the slot is really big, you want to use a screwdriver that will fit properly in the size of slot so that you don't deform or damage the jet.
 
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