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Thursday, May 26, 2011

Oily facts

This post will be about oil. You might think; what does oil has to do with scooter tuning? Well, more than you might think.

Read on to find out!

So why exactly isn't just any oil good for just any engine...?
The main reason is that with higher rpms, things get hotter and pressure rises inside the engine. Not all oils can handle these hot temperatures and pressures. They will burn with the gasoline and lose their lubricating function. This means extra friction and with this friction comes heat = less power and engine failure. The first and foremost function of oil is thus lubrication. Next to this it provides cooling (with the gasoline) to the internals of the engine. 


There are three sorts of oil that can be used with scooter engines. 
- Mineral oils
- Semi synthetic oils
- Fully synthetic oils

The mineral oils are made from crude oil and have no additives. 

The semi synthetic oils are a blend of mineral oil + engineered additives.

Synthetic means that is man made, engineered. This is the reason why fully synthetic oils are more expensive (the research behind it).

You should find the oil that matches your use of your scooter, it is a bit of a waste to spend money on high grade oil if your setup is low reving and you use your scooter as a daily driver (stopping, accelerating, stopping, waiting etc). For these low performance scooters I would advice to use semi synthetic blend of oil. Because it is a blend of mineral oil and engineered additives, you save on money, but still have the benefits of the engineered additives of the oil. These additives are engineered in a way that the oil can be used with the oil injector system (50:1 ratio = 50 liters of gas : 1 liter oil) and provide low emissions, low carbon deposit build up (clean combustion) and enough cooling and lubrication of the engine.

If you upgrade to a 70cc cast iron cylinder that is still below 10 000 rpm, you can suffice with the semi synthetic blend and the stock oil injector. If you have a "tuned" cast iron cylinder (e.g. Polini Corsa or similar) you might want to switch to different type of oil. One that accommodates more sportive driving.

I recommend to ditch the oil injector when you driving a "mid-race" cylinder or up and start mixing yourself. The reason why is that oil injectors are setup to be economical and environmental friendly (50:1 or higher). That means that they do not provide higher reving setups with enough oil. Besides this they are also likely to fail when rpms are getting higher (12k+ rpm). Also with the high power 180cc engines it is wise to start mixing yourself because your engine will need more oil. A higher performing engine gives a bigger bang with each cycle, generating more heat.

For high performance engines I advice to mix at least 35:1 ratio if there is no instruction from the manufacturer. Otherwise follow manufacturer instructions.

I created a table for you that you can use when you start mixing yourself. You can print this scheme (click it to enlarge), laminate it and place it inside your buddyseat. The table shows how much oil you should add to your gas tank.


Most oil bottles have an indicator on the side in steps of 100 ML. Which lets you determine how much goes in the tank. Unfortunately this is not very precise. Of course you could add a little extra, but that mixes up the ratio between gasoline and oil. Next to this, if you use expensive oil this method is somewhat a waste of money. Another reason is that pouring oil from the bottle in the gas tank can be somewhat messy.

My buddy Vilhelm came up with a smart idea of using a syringe to get oil from the bottle and inject it in the gas tank. I really like this idea, because it is precise, clean and fast. See this movie below how it works (click FHD):


These syringes are cheap can easily found on Ebay.
Having your bottle of oil, mix ratio table and syringe in your buddyseat, will insure that you will always add the right amount of oil to your gas tank with each gas stop. And of course, no more messing around with pouring oil from the bottle in your tank, spilling it all over your buddyseat and helm storage compartment.

Thanks for reading and stay tuned!

Bram

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