cleaning my carbs

ok guys. i have gotten some really good info from you so far. lets keep it goin... my throttle wont even move the carbs body. it moves a 1/8th of a " then stops.

i have cleaned mc carbs before but they were out of a yamaha maxim xj550. i have some carb cleaner, but before i soak my carbs i need to take some things apart. the floats are very tough to move. only 1 is free. so what i want to do is take the pin out that holds the float and clean those parts seperate. now as for the jets. are these the jets in my picture? they were bottomed out, tightnened all the way down. and if they are not the jets, where are they?

is there anything else i should really focus my attention on while cleaning??

......where my jets...lol

That is ALOT of varnish, but I have rescued worse. varnish does not necessarily determine condition...

Dissasemble the entire rack.

Compeltely dissasemble each carburetor.

Remove all rubber components.

Completely submerge carbs and all metal parts in a carb approved dip solution and leave them overnight.

Once removed from carb dip, use strong compressed air, and blow it through all of the carburetor passages. Confirm the passages are clear by spraying (with straw) carb cleaner through the carb passages and verify flow into bore. Make sure all carbs have visually consistant flow.

Once carbs are dry, re-assemble with appropriate carb kits.

Use as much new rubber as possible.
carbs need to be super clean to function properly.
... this is what I would do

Good luck!



PS. Nice close-up pics.

how do i disesemble the rack?TeK9iNe wrote:

That is ALOT of varnish, but I have rescued worse. varnish does not necessarily determine condition...

Dissasemble the entire rack.

Compeltely dissasemble each carburetor.

Remove all rubber components.

Completely submerge carbs and all metal parts in a carb approved dip solution and leave them overnight.

Once removed from carb dip, use strong compressed air, and blow it through all of the carburetor passages. Confirm the passages are clear by spraying (with straw) carb cleaner through the carb passages and verify flow into bore. Make sure all carbs have visually consistant flow.

Once carbs are dry, re-assemble with appropriate carb kits.

Use as much new rubber as possible.

... this is what I would do

Good luck!

also in this first picture i use my figer to try and open the throttle of the carbs. it moves about an 1/8". also the second picture moves just a little. am i doing something wrong?

its like its hitting something. it only moves a little....

how do i get the rod out that goes through all four carb bodies?

i took the countersunk screws out and its lose now, but the rod that goes through all the carbs....how the F do i remove it?

To dissassemble the rack and remove the rod that lifts the needle slides:

Remove the small bolt that is located on each slide arm, located directly above the rod. Then remove the small rod stopper that is between 2 carbs (Part# 13,14,15), and looks like a small fork against the rod, held in place by 1 screw to the intake plate assembly.
Then remove the end rubber caps, lubricate the rod generously, and push/pull the rod out.

To dissasemble the rack, simply remove the rod mentioned above, and the choke plunger rod (Part# 10, similar method to rod), and unscrew the large screws (2 per carb) holding each carb to the intake plate.

here's a diagram to help:

This way, you can just refer to parts numbers in the diagrams.

carbs are apart and soaking.

Part 1

I know it's mentioned not to take the carb rack apart, but sometimes you have no choice.

Carb Cleaning 101

By M. Shively

The elements of internal combustion engines are: correct fuel/air ratio, spark at right time, and adequate cylinder compression.

There are many passageways and openings to check and clean. All are important in function and when obstructed or not working properly, have subtle to radical effects on engine performance. Vacuum leaks and carburetor synchronization also effect performance and should be inspected and adjusted following the below procedures.

Warning: Remove all rubber parts before you begin. These parts usually include vacuum diaphragms, needle valves, o'rings, hoses, and other parts. Spray cleaners will damage these parts. Do not disassemble individual carbs from the carb bracket.

Air & Fuel Passageways: Trace and learn individual fuel and air circuits from beginning to end. Machines can only drill straight through the cast passageways. To change direction, another angled passageway must be drilled. The union is plugged with a brass or bronze bead. Inspect and clean each passageway with spray cleaner, brushes/pipe cleaners/etc, and compressed air. Remove any discoloration and debris. Look for spray cleaner to exit from one or more passageways.

Jet Cleaning: Inspect jets by holding to light and look through them. You should see an unobstructed round hole. Clean the jets with one or more of the following: jet cleaning wires, soak solutions, carb spray cleaners and compressed air. Re-inspect jets after cleaning and install when clear of obstructions. Some main jets have paper-like gaskets. Most have metal spacers between the jet and the emulsion tube. Some screw directly into a brass emulsion tube which is machined for a 7mm wrench at its float chamber exposed base.

Inlet Fuel Valve: Inspect the needle valve & spring. Press down the tiny metal rod that protrudes from the butt or float end of the needle valve. The spring should move freely and return the rod to its location. Check the needle valve's seat area for a groove or other wear. It should appear highly polished. Some needle valve seats are rubber and wear may not be visible. Inspect the needle valve jet seat. You can clean the jet seat with Q-tips and semi-chrome polish if necessary.

Carb Body Castings: Blow air through the atmospheric vent holes located on the dome of each float bowl chamber. Air should exit via hoses or brass nipples. Inspect the emulsion tubes and passageways (cast towers that jets thread into) for discoloration and debris. Clean interior emulsion towers with a soft bristle gun cleaning brush. Clean each Venturi (main carb bore).

Needle Jets & Jet Needles: Clean the needle jets, jet needles, and passageway or tower that needle jet screws into. Clean the emulsion tube (pipe between needle jet and main jet) (Main Jet may screw into emulsion tube). Jet needles are part of the throttle slides. See below…

Throttle Slides: There are several types of throttle slides: Mechanical linkage, vacuum, diaphragm, and cable. Disassembling the jet needle from the slide is not always required for cleaning. If you have vacuum piston type throttle slides (large diameter solid metal slide), avoid cleaning the lubrication from sides and caps. If piston type check cap vents and passageways with air. Clean if necessary and re-lube. If you have rubber vacuum throttle diaphragms, inspect for dry-rot, defects, and tears by gently stretching rubber away from center. Do this until all areas around diaphragm have been inspected. Replace any defective part as described above. Clean carb body areas around diaphragm including air passageways and air jets. Diaphragms have a locator loop or tab fabricated into their sealing edge. Observe this locator upon reassembly. Avoid pinching the diaphragm when reinstalling caps.

Fuel Screws: Fuel screws have sharp tapered ends. Carefully turn one fuel screw in while counting the turns until it seats lightly. Warning: These screws are very easily damaged if over tightened into their seats. Record amount of "turns-in" and remove the fuel screw, spring, washer, and o'ring. The fuel screw is part of the enrichment (choke) circuit...clean passageways as described above. When carbs are assembled, spray low PSI compressed air into diaphragm air vents located at intake side of carbs. Throttle slides should rise, then fall when air is removed. Lightly lube external moving linkages. Reinstall carbs and follow through with carburetor synchronization.

Throttle Cables: Lubricate cables periodically. If cables are disconnected from carbs or removed for replacement, etc . . . remember cable routing and ensure proper reinstallation routing. Avoid bread-tying, sharp bends, and pinching cables. Adjust cables so throttle grip has about 5mm of play or throttle slides or butterfly valves may not open completely (full throttle)(wide full open).

Float Bowls: Inspect float bowls for sediment, gum or varnish, crystallization, and defects. Clean all pipes, tubes, passageways, and embedded jets with cleaners and compressed air. Remove and clean the drain screw and area. Inspect bowl gasket and replace if necessary. Clean and inspect overflow pipes and tubes, look for vertical cracks.

Floats: There are several types of float materials: plastic, brass, black composite, tin, and others. Handle floats carefully. Avoid bending, twisting, denting, or other means of mishandling. Most floats are adjustable by bending a small metal tab near the float axle end. Do not change the float adjuster tab unless tuning fuel service levels. Clean metal floats by soaking or by spraying cleaner and wiping clean. Other material type floats may require replacement if cleaning is necessary. Inspect the needle valve (float valve) and seat. Check needle valve's spring loaded pin. It should depress and return smoothly and without resistance. Check the needle valve's tip for a worn groove. Replace needle valve and seat if either symptom exists. These parts wear together and must be replaced as a set.

Synchronization: This is a fine adjustment performed usually and preferably with the carbs installed and the engine running. The unusual part is performed with gauged wire with the carbs on the work bench. Carburetor synchronizing balances Venturi vacuum at the exhaust side of each carburetor, resulting with smooth idling and optimized performance at all throttle openings. Synchronization is checked using a set of gauges which are either air vacuum type or liquid mercury type. The gauges are connected to vacuum ports on the intake manifolds via nipple tubes or if sealed with screws, sync gauge adapters will be needed. With the engine running at temperature, and with a fan or means of forced convection aimed onto the engine, the carbs fuel screws and idle are adjusted, then the synchronization is adjusted via adjustment screws on the carbs. A reserve fuel tank is recommended for convenience of accessing carbs during this procedure. See gauge instructions and repair manuals for detailed use of synchronization gauges.

Notes: While carbs are apart, record the jet sizes. Look for a very small number imprinted on the body of the jets. Verify that numbers are the same for all jets on models with in-line cylinders. A few transverse-4 models and V-engines, the inner and outer carbs use some different size jets and it's important to not mix them up. If you have dial or veneer calipers, measure and record float heights. Perform measurements with floats just touching needle valves, though not depressing the needle valve rods. Replace fuel and vacuum hoses. Be sure to use fuel rated hose for fuel. Install or replace in-line fuel filters. It's a good time to remove and clean interior petcock fuel filters. Inspect carb manifolds for dry-rotting, inspect all clamps and air ducts. Inspect, clean, lube, and/or replace air filter(s).