Classic Motorcycle Build

Kawasaki KZ650 Remove and Install Carburetors

Article and Pictures by Mark Trotta

Here's a step-by-step tutorial on how to remove and install carburetors from a Kawasaki KZ650. Other four-cylinder Japanese bikes will follow a similar procedure.

Kawasaki KZ650 carburetor removal

Like most UJM's, carbs are removed from the engine as a complete assembly.

Getting Started

First, find a place where you can get to both sides of the bike easily. After shutting off the fuel valve, disconnect hose from gas tank. I put an old pan underneath the bike to catch any spillage.

Remove Gas Tank

On early models like this 1977 KZ650, a quick tug pulls the back of the tank out of a rubber grommet. Later models have a rear tank bolt.

Kawasaki KZ six fifty with gas tank removed

Lift tank up and back, and find somewhere safe to keep it.

proper motorcycle gas tank storage

Rolling storage box, aka 1961 Harley Servi-Car

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Spring Clamps and Boots

Just behind each carb, there is a spring band clamp which secures it to the air box boot.

Kawasaki KZ650 removal

I was able to roll them back and out of the way by hand.

Kawasaki KZ six fifty maintenance and repair

If yours are stubborn, don't use anything pointy to remove them, as it may puncture the rubber boots.

Loosen Front Clamps

In front of each carburetor are mounting clamps, which need to be loosened.

Kawasaki KZ650 carburetor removal

Depending on how the last guy put them on, the two inner ones may be a little awkward to get to.

Remove Air Box?

The factory service manual recommends removing the air box during carb removal, but it's really not necessary.

Remove Air Box Boots

With a heat gun, slightly warm the rubber boots to make them soft and pliable. You'll then be able to push them into the air box. This will make enough clearance to remove the carb rack once everything is loosened and disconnected.

Kawasaki KZ650 carb to air box boots

CAUTION: Careful with the heat gun! You can literally melt the rubber. 20 to 30 seconds per boot is enough to make them softer.

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Bottom Vent Hoses

Remove vent hoses on bottom of each carb.

Kawasaki KZ six fifty repair

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Remove Throttle Cables

First, slacken cables at handlebars.

remove throttle cables Kawasaki KZ650

An 8mm open-end wrench is needed to loosen the upper lock nuts.

8mm combination wrench

On the other end, slacken and remove cables from the pulleys.

Kawasaki KZ six five 0

A 10mm open-end wrench is needed to loosen the lower lock nuts.

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Upper Vent Hoses

Depending on year and model, there may be vent lines on #1 and #4 carburetors.

Kawasaki KZ650 carburetor vent lines

Because it's difficult to get your hands on them, I waited until everything was loosened and removed, then pulled off the vent lines just before removing carb rack from engine.

Kawasaki KZ650 remove carburetors

With both hands, pivot carb rack downward and it should pop out of place. Remove from right side of bike.

Kawasaki KZ650 repair and maintenance

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Reinstall Carburetors

Working from the right-side of the bike, I held the carb rack with one hand, while connecting the upper vent hoses with the other hand. The four lower hoses can be installed after the rack is back on the cylinder head.

Kawasaki KZ650 repair and maintenance

I found it difficult to line up and tighten the front clamps, so I used a block of wood to prop the rack in place while tightening.

Once all four clamps are tight, the air box boots may be reinstalled.

Install Air Box Boots

Yup, this is the hard part. Even after heating them up with a heat gun, they'll still give you a hard time going back in.

Kawasaki KZ650 install air box boots

TIP: If you're working without gloves, leave the spring clamps off when you heat them up - the metal gets much hotter than the rubber does!

Kawasaki KZ650 repair and maintenance

Re-install spring band clamps when boots are back in.

Next, re-connect throttle cables and adjust.

Kawasaki KZ650 replace throttle cables

Working with the threaded fasteners and lock nuts, tighten until the slack is removed from both push and pull cables.

Re-connect lower vent hoses.

Kawasaki KZ six fifty repair

Pictured above: Typical vent hose routing under bike.

Re-install gas tank and connect fuel hose.

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Notes and Misc

what is a JSS screwdriver

Read: What Is A JIS Screwdriver?

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