Maintaining the condition of an old motorcycle is a bit more difficult than that of an older motorcycle, but once the condition is improved, the motorcycle can often be driven normally afterwards. However, once the condition is improved, the motorcycle can be driven normally. However, it is a fact that repairing old motorcycles is not an easy task without specialized knowledge. The Kawasaki W1 series is one of the most popular vertical twin motorcycles in Japan, and is known for its high level of heartbeat vibration, which can cause the bolts to loosen easily.
Carburetor threading can also be repaired!?
The right-angle fixing seat called "Ikale" is placed on the face plate of the drilling machine, and at the same time, the carburetor is brought to the Ikale surface, and the carburetor is fixed with the flexible clamp so that the float chamber surface becomes a right angle. The carburetor is fixed with the flexible clamp so that the float chamber surface is at right angle. When fixing the carburetor with the flexible clamp, we used the wood to hold the carburetor body so that it would not be deformed. Once the carburetor was fixed perpendicularly to the drilling machine faceplate and eqail, we drilled the fuel hose threads to the size of the pre-drilled holes. I shaved off the damaged threads and made new ones.
It is important to set up the tap so that it does not tilt.
After finishing the preparation hole, set the special tap for inserting the threaded repair coil (a product called recoil, sprue or helicert) in the chuck of the drilling machine, and bite the tap by hand so that it is perpendicular to the banjo surface of the cab body. Once the tap has been inserted to a certain degree and a path has been established, the tap handle is used to finish the remaining threads. A lot of experience is required for this work. If the threads are bent, it will immediately lead to a gasoline leak.
The lower hole for the screw coil insertion was completed. In the case of Mikuni carburetors for Kawasaki W1, it is good that there is still enough thickness to insert the screw coil, but in some cases, carburetors that cannot be physically repaired like this = too thin to do anything about it.
Insert the screw coil into the machined thread
M10P1 on the newly rebuilt screw thread.Insert the threaded coil for the 25 banjo bolt.
Each manufacturer of screw coils has a different type of insertion jig. This one is made by Sprue.
A bent lead section is visible near the bottom of the screw. This lead should be removed after the work is completed.
I used a special tool to hammer in the screw coils (here I used a product from Sprew Japan). This will increase the strength of the screw threads. The threads where the banjo bolts meet the cab body's aluminum and steel bolts are now iron and steel, allowing them to be tightened securely.
Cut the lead = tongue during insertion
Since the threaded coil has a bent part called the lead part (commonly known as the "tongue"), tap it lightly with a flat punch or the like to fold it, and then pick it up with tapered pliers or the like. Be sure to do this work. If you forget to cut it off, the banjo bolt will push through the tongue and cause problems later on.
Now you can rest easy with this banjo joint.
This is the banjo where you insert the fuel hose on the Kawasaki W1. When tightening the banjo, be careful not to over-tighten the threads. The engine vibrations can easily cause the threads to loosen, so it's even easier to damage the threads. Yamanouchi Carburetor in Osaka, Japan, who helped us with this project, has prepared aluminum packing washers of different thicknesses to adjust the depth of the banjo bolt tightening thread and to adjust the compatibility with the banjo, so that the banjo joint can be tightened under the best conditions.
Interview Cooperation: Yamanouchi Carburetor
- Point 1: It is good if there is a thickness that can be processed, but when there is no thickness, it is necessary to give up.
- Point 2: It is necessary to fix the body firmly so that the drill will not be inclined during the preparation hole processing.
- Point 3: When inserting a screw coil, adjust the insertion until the coil end sinks below the first peak.
- Point 4: After inserting the screw coil, be sure to remove the lead = tongue part, or it will cause trouble.
As you can imagine, there is a deep cause-and-effect relationship between the condition of an out-of-print motorcycle and the condition of its carburetor. The carburetor is one of the precision parts of any 2-stroke or 4-stroke engine. However, they are also easy to disassemble, which is why many old motorcycle enthusiasts do DIY maintenance on them. If the problem is simply caused by dirty passages or a malfunctioning float, it can be fixed by simply reassembling it correctly.
However, it is not uncommon that a user who has little experience in maintenance disassembled the float and caused irreversible trouble, such as a screw thread was damaged during disassembly or a pillar supporting the float was broken by forcible disassembly is not uncommon. There may be some riders who have encountered such regrets that they cannot regret. If a carburetor has suffered such a serious problem, it will most likely be unusable. However, if you are a professional and an experienced mechanic, you will be able to use it again? It is important to remember that there are cases in which carburetors that were thought to be
The Kawasaki W1 carburetor we were repairing here had a problem with the fuel hose fitting. The banjo bolts holding the fuel banjo joints were loosened by the engine and riding vibrations, and after repeated retightening, the threads were ruined. This is a common problem with Kawasaki W1 carburetors, especially in the UK.
If you find a problem and wonder if it is difficult to fix, it is better to ask a professional for help. In fact, there are many cases where trying to repair and rebuild a product can make the problem even worse. Professional mechanics who have a lot of experience in repairing and reconditioning motorcycles can do the job without a hitch, but it is because they have a lot of experience that they can do it. Even so, it is the nature of Sunday mechanics to want to take on the repair challenge themselves.
