Soaking and Cleaning Works Best for Carburetors that are Covered with Dirt!

The first step in motorcycle maintenance is to clean every part of the motorcycle. It's no wonder that a dirty motorcycle is so hard to find. Some of the carburetors on older motorcycles are soaked in fuel and oil that they are unbearable to look at, but this is where a soak-in-the-blue cleaner rather than a spray-on cleaner comes in handy.

Heating is a good way to keep the piston valve from sticking

A piston-valve type carburetor allows the throttle valve to be opened and closed directly by the throttle cable. However, if the fuel has hardened and stuck to the gap between the carburetor and the piston, it may not move completely. In that case, you can heat it up with a heat gun and it may come off. You can dip the throttle cable into the cleaning liquid with it attached.

Scratches and fading in out-of-print motorcycles and old motorcycles can be regarded as a medal of accumulated history. This is because it is impossible to create a period style in a restored motorcycle, which cannot be created by repainting or re-plating because it cannot be created in a short period of time.

However, it is only a matter of degree, and as the dirt piles up, it will only get dirtier. Speaking of the engine area, fuel and oil oozing is wet at first, but as time goes by, it becomes a paste, and the viscosity increases and sticks.

The HS1, launched by Yamaha in the late 1960s, is a two-cylinder moped with a 90cc two-stroke engine. 90cc but with two cylinders, it was equipped with a twin carburetor and was popular as a little twin at one time, but it has remained immobile for nearly 30 years Vehicle.

Fortunately, the kick pedal went down smoothly, and when I removed the plug and checked the ignition spark, I saw crackling sparks on both cylinders, so I cleaned the dirty carburetor and poured the mixture over them to see if they would start.

The piston valve type carburetor should be able to pull out the throttle valve if you remove the top cap, but the cap will come off but the piston will stick and won't come off. This is a symptom of the fuel left inside the carburetor that has turned into a resinous, glue-like substance.

Trying to force the throttle or prying the throttle valve by trying to turn the throttle or by sticking a screwdriver into the venturi can sever the throttle cable or scratch the throttle valve, so in these cases, applying heat to the throttle body with a hairdryer or heat gun will help. The heat will often soften the resinous fuel and allow the throttle valve to pull out.

This method also works well for negative pressure carburetor piston sticking, but be careful not to overheat the vacuum pistons, as they have rubber diaphragms built into them. When using a heat gun, push the piston up while heating it evenly from a distance so as not to damage the diaphragm.

The application of heat softened the dirt and allowed it to pull out with both a slippery hand. There was still a netting of dirt on the sides of the pulled out piston, which seemed to act as a glue when it was cold. Do not push the throttle valve up with a screwdriver in the venturi when it's cold, as this can cause damage to the cutaway portion underneath the valve.

There are two types of carburetor cleaners: spray and immersion types

There are two types of cleaners for cleaning disassembled carburetors: spray and immersion cleaners. The spray type is further divided into liquid and foam types, and in order of convenience, they are liquid spray, foam spray, and immersion type.

For stubborn dirt, the foamy spray type or the immersion type, which is submerged in a liquid, is best for particularly heavy dirt. Even the spray type can be used to remove dirt if the carburetor is disassembled, lined up on a butt, and sprayed to the point of sinking, but the immersion type, which is submerged in a cleaning solution, is even more effective at cleaning.

Yamalube Super Carburetor Cleaner from Y'S Gear seems to be the most popular immersion type carburetor cleaner. It's an undiluted type that is diluted with fuel, and although the undiluted 4-liter bottle is reasonably expensive, it's not bad value for money since it can be reused if you store it in a container (although its cleaning power will decrease with repeated use).

It works best if it's completely disassembled and soaked

Yamalube's Super Carburetor Cleaner (the product shown in the image is the older type) is a reputable immersion type carburetor cleaner. It is mixed in a ratio of 7:3 fuel to the undiluted solution to soak the carburetor parts. Note that it cannot be used on rubber materials such as negative pressure carburetor diaphragms and rubber-tipped float valves.

After an hour of soaking in the Super Carburetor Cleaner, the aluminum alloy body and float chamber as well as the brass jets and needles will be surprisingly clean. The bottom of the float chamber on the right has a rough cratered surface due to corrosion, but the dirt in the small bumps has been completely removed.

The main strength of the Super Carburetor Cleaner is that its cleaning ingredients are liquid and have a high penetration rate, and it has a high ability to dissolve varnish and 2-stroke oil-related dirt.

There are some spray cleaners that have a strong cleaning power, but for the ability to get into the fine air and fuel passages inside the body, this soaking type is the most effective. Even jet holes blocked by sticky dirt can be lightly poked with an ultra-fine jet cleaning tool to create an opportunity for it to penetrate into the dirt and dissolve, without affecting the jet diameter.

Another advantage is that the texture of the carburetor material is not greatly affected after cleaning, as aluminum becomes white, which is typical of aluminum, and brass jets have a brass shine to them. If the carburetor is soaked for too long, it may be discolored as if it were burned, but if the soaking is only one or two hours, there will be no significant effect.

It's a good feeling to have a stuck carburetor back in service. (It's safe to use mixed fuel to check the start until you can confirm it) and the engine started successfully.

If you're not sure if the engine is really going to start, it's easier to be prepared for the rest of the day if you just check the start-up rather than taking it apart out of the blue. If the kick pedal is down, you can check the plughole with your finger to see some compression, and sparks are flying off the plugs, you can just clean the carburetor and send fresh fuel to see if the engine will start or not.

With a 4-stroke engine, you want to change the engine oil, but with a 2-stroke you don't have to.

That's why it's important to clean your carburetor efficiently, and choosing a high-performance carburetor cleaner is a shortcut.

The contrast between the dirty crankcase and cylinders and the bright white carburetor is too bright. It looks much more beautiful than it did before the job, and the internals has been completely cleaned, so it's in perfect condition for checking the engine start. Once the engine is running, the condition of the piston rings and crank bearings can be determined so that we can predict how far the engine itself will need to be taken apart for repairs.