The reality is that it is very difficult to even disassemble and clean a carburetor that was completely stuck.
We managed to disassemble the 4-stroke carburetor by boiling it in a kettle.
Here, we are going to clean the genuine carburetor for the Kawasaki air-cooled Z even more thoroughly. Here is a report on how it went.
Separate each cylinder and start cleaning.
After confirming that the piston valves operate up and down, the four-carburetor was disassembled into pieces.
First, the throttle shaft that synchronizes the throttle linkage is pulled out, and then the eight countersunk screws that secure the carburetor body to the four-cylinder plate are removed so that each of the four carburetors becomes a separate unit. Once the carburetor has been disassembled to this point, maintenance of the single-cylinder carburetor is the same as for a single-cylinder carburetor.
Don't be in a hurry to disassemble severe sticking.
Even if you can confirm that the piston valve operates up and down, where it does not operate smoothly, pull out the throttle valve while warming up the body with a heat gun here as well. Be careful not to burn yourself.
The entire periphery of the throttle valve that was pulled out was covered with a sticky, gooey, tar-like varnish. When this stickiness cools down, it seems to act as an adhesive again and stick together. Since the stickiness was also adhered to the needle of the jet needle, the inside of the needle jet with which it is to be combined must also be sticky with varnish. By completely disassembling the needle-jet, it is possible to clean it completely. The plunger for the by-starter function is often stuck and cannot be pulled out. Do not pull it out by force, but warm the area around the body with a heat gun before removing the plunger. The plunger condition is also important. The throttle valve pulled out of the body is separated from the linkage and valve by removing the two Phillips screws tightened inside.
Let's proceed with the work without any haste.
Start cleaning by managing & disassembling each cylinder.
If the disassembled carburetor parts for each cylinder are stored mixed up in a single container, it will be difficult to restore them when reassembling. It is best to keep them separated for each cylinder. It would be best if each cylinder could be cleaned afterward.
Can use a tea strainer net.
It would be best if the parts could be cleaned separately for each cylinder, but in this case, they were mixed together.
If you want to clean the small parts of each cylinder separately, the use of stainless steel round tea strainer net is definitely convenient. Small parts can be managed cylinder by cylinder by cleaning them in this net. A Tupperware with a lid is more convenient than you might imagine when cleaning parts by soaking them in carburetor clean chemicals. Many kitchen utensils are useful during carburetor maintenance. When using Yamalube's Super Carburetor Cleaner undiluted type, let's use around 3 hours as the standard soaking time. Excessive soaking will damage the parts. The bottom of the float chamber was covered with a thick layer of varnish and tar, but it cleaned up beautifully. If dirt is left behind, it will be primed and the dirt will progress faster.
Fuel kits are a reassuring ally.
Key Star's fuel adjustment kits can be relied upon when overhauling the OEM carburetors of old cars and Keihin special carbs such as CR Special/FCR. For example, it is possible to set the carburetor to suit engine conditions such as reduced compression pressure due to years of operation. That is a feature of the fuel adjustment kit. The most exciting feature of the kit is that it includes various gaskets and O-rings.
POINT
Point 2 - Keep disassembled parts from mixing between cylinders!
Point 3 - Use a variety of containers in an imaginative way!
The four-carburetor carburetor, which had been left unattended for several decades and was severely sticking, could be set up in an easy-to-maintain condition by washing the entire carburetor in a boiling pot using a no-longer-needed skillet. After washing the carburetors in hot water mixed with a cleaning solution, disassembling the carburetors became much easier. A neglected carburetor is prone to damage to the heads of the various tightening bolts and screws. However, the body of the carburetor was warm immediately after cleaning, and the cleaning solution penetrated deep into the bolt grooves, making it possible to loosen the bolts very smoothly. It is best to keep track of the dismantled parts by cylinder and work on each cylinder separately when cleaning. Unfortunately, we did not have enough containers at the time of the work, so we had to use the same containers for cleaning.
The chemical used for the full-scale cleaning was Yamalube Super Carburetor Cleaner undiluted type.
By using the manufacturer's recommended dilution ratio and dividing it with fresh fuel (it is essential to use fresh fuel), the chemical exhibits a cleaning ability that exceeds expectations. The outer circumference of the throttle valve, which we could not easily disassemble, was covered with a tar-like varnish that was more persistent than we had imagined, and while the parts were sticky when warm, they were like the glue that sticks to the parts when they cool.
By using this carburetor cleaner, the throttle valve and needle, which are now single parts, could be disassembled and cleaned cleanly. To prevent the loss of small parts, a ball net for tea strainers was used, and this tool is also quite easy to use. Stainless steel net baskets are also available at 100-yen stores, so it is a good idea to have a few of these available for carburetor maintenance.
The carburetor itself is best soaked in a carburetor cleaner solution to dissolve dirt, and then cleaned more vigorously with an ultrasonic cleaner + degreasing solution. The power of the ultrasonic cleaner is indeed great, and it can remove dirt even in small areas that are difficult to remove by scrubbing with a brush. We can only hope that a compact and affordable ultrasonic cleaner for Sanmeka will appear on the market soon.
