Kawasaki KZ650 cafe-racer. Carburetors. Part 1.

This post, be it put in one part, would contain about forty photos. So I am to cut it  in two.

The question of KZ650 carburetors is quite extensive. One may catch a serious case of headache just counting modifications of Mikuni VM24 that were installed on 650 during years of its manufacturing. My knowledge in this  is quite superficial, however I counted two modification of VM24 without accelerator pump and three modification of VM24 with accelerator pump. Engine on which I based my project had carburetors without accelerator pump and with late type of pilot screw that adjusts air. However, as soon as I learned about VM24 with accelerator pump, I became curious about it.  One may find information that those accelerator pump implicit fuel mix only on idle, so to say produce single jet of fuel in every carburetor when you jerk throttle to start moving. However, only one modification of VM24 with accelerator pump has closing fuel valve (triangle thing on float bowl of second carb), and vacuum actuating circuit that causes valve closing on higher rpm. Second modification of “pumpers” still has valve, but it has no actuating vacuum channel. And the last, third modification has no closing valve at all. Thus, in these two types of VM24 there is no reason for accelerator pump not to work on other than low rpm.  However, its only my suggestion and I couldn’t confirm it until I finish with “pumpers” I bought for the project. And even if experiment with accelerator pump will lead me nowhere, I could deactivate all pump system just by replacing float bowls with bowls form carburetors without pump.

So I bought modification of “accelerated” carburetors with closing valve but without actuating channel. They turned out to be in very good condition:

Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetorsAccelerator pump and closing valve:

Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetorsSure, forty-years-old carburetors need to be completely rebuilt and cleaned through and out. So I put them apart. Counting age, insides also looked rather nice.

Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetorsSome soot, dirt and depositions in my opinion are manageable.

Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetorsTo my knowledge, there is no vapor blasting here in Ukraine . The closest thing we have is a workshop that specializes on glass beads blasting, which has a range of glass beads of different size and thus coarseness.  But even if there was vapor blasting available, I am not sure that I would dare to use it on carburetors, as it is also media blasting. I also don’t like how blasted aluminum looks, so my way is simple: carburetor cleaner, brush and those synthetic detergent I used on crankcases. It works nice and removes all visible depositions, so there is no reason to consider it moght leave invisible ones untouched. I like how carburetors look after cleaning:

Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors Kawasaki KZ650 VM24 carburetors

To be continued.

 

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