IT’S all about the Filters!
Welcome to this week’s tech talk at Venom Motorsports!
This week we are going to follow up our discussion of proper combustion and engine maintenance.
Today we are going to spend some time discussing filters.
Please click on our “youtube” videos on filters from the links below.
Keep in mind that this information applies to all of our fine gas powered Super Pocket Bikes, Dirt Bikes and ATVs!
Ok onto this week’s topic.
Tim...Combustion seems like a complex discussion where do we begin?
To begin with we need to review the combustion KABOOM equation.
Spark + Fuel + Air = KABOOM!
When KABOOM occurs the piston is pushed downward in the engine cylinder, which turns the crankshaft, which turns the gears in the transmission, which drives the chain, which turns the rear wheel gear, which makes you go zoom! So KABOOM is most important!
Today we are looking at the Air side of the KABOOM equation.
When we combust a fuel we are oxidizing “burning” the carbon and hydrogen in the fuel. When carbon and hydrogen burn properly we produce Carbon Dioxide and Water as by products of proper combustion. So when you look at the exhaust coming out of your bikes engine you should see a pretty clear gas, which is made up of Carbon Dioxide and Water vapour in the form of steam.
Tim...What affect does a dirty air filter have on the combustion process?
A clean air filter is very important for proper combustion. If the engine is not getting enough combustion air, the air fuel mixture will be very rich. It will contain more hydrocarbons then the available air can completely combust. This results in unburnt hydrocarbons leaving with the exhaust gases. If the air fuel mixture is very rich you will see that the color of the exhaust gases has changed from pretty clear to a much darker even blackish color.
Under these conditions the combustion process is poor and not good for the environment at all. The unburnt carbon will also produce carbon monoxide which is a hazard for us. If you were in a space without ventilation and subjected to a high level of carbon monoxide you would turn to a nice “smurf” like blue skin color deprived of oxygen, pass out and die. Not good!
So always, always, always ensure that you run your bike in a well ventilated space! Yeah Always!
Tim...It sounds like having a dirty air filter produces results similar to running the bike with the choke on all the time. Is that right?
Yes! That is correct. When you engage the choke on your bike, you are causing a very rich air/fuel mixture to be delivered into the engine.
This really rich air/fuel mixture is great when trying to start a “cold” engine, but terrible on the engine once it is warm.
If you run your warm engine with the choke on....it will “bog” down, have low power and not feel right. Very similar to the results you can expect if your air filter is plugged up with dirt.
Also your spark plug will become fouled with a blackish residue “soot” which is in fact un burnt carbon.
Tim...How can you tell if the air filter is dirty?
That is very easy. Just remove the air filter from the carburetor and hold it up to a light source.
If the air filter is clean you will be able to see light right through the filter membrane.
If the filter is dirty you will not be to see through it at all.
So when the filter is dirty, replace it. If you are out riding in very dry sandy areas you could also cheat a little and use a vacuum cleaner to remove contaminants on the exterior of the filter. This will help to keep the filter membrane a little cleaner and extend the life of the air filter.
Never ride your bike without an air filter, otherwise all of the contaminants in the air will be going right into the engine cylinder and this can cause damage.
A dirty fuel filter will also affect the combustion process. If the fuel filter is dirty it will restrict fuel flow and rob the engine of power.
Tim...Does my bike have an oil filter too...like a car?
Automobiles have an oil filter and its purpose is to clean the oil and remove contaminants. This means that the engine oil in your car’s engine is always pretty clean and free of particulate material. When you go for an oil change, you change both the engine oil filter and the engine oil itself.
Larger motorsport bikes do have oil filters, however smaller displacement bikes do not.
Your bike does not have an oil filter, so changing the oil regularly is very important. The contaminants in your bikes engine oil fall out of solution and sit in the bottom of the engine/transmission crankcase oil sump. So when you give your bike an oil change it is always wise to add a little fresh oil after draining the oil sump to help flush the contaminants out of the oil sump before you top the engine up with clean fresh oil to the top of the dip stick.
What do these contaminants in the oil look like? Well, the contaminants are little pieces of metal that have worn off of various components in the engine. They look like metal fillings.
This occurs as the metal parts move against each other in the engine. So an excellent motor oil is really critical! I will be reviewing lubrication and the “break in period” of your bike in next weeks blog.
If you have any tech questions about our bikes, please feel free to email them to...
To watch this air filter topic on video click here
Check out our blog next week as we look at “break in period” and lubrication on your bike.
Till then, Enjoy the ride!
Technical Support Specialist
Venom Motorsports Canada