If you’re new to riding two-strokes, or you’re just wondering if there are better premix options, you have come to the right place. When it comes to motorcycle premix your selection is crucial for the longevity of your two stroke engine.
What is premix?
Premix is an oil lubricant that you mix into your fuel for two-stroke engines, in order to preserve your top engine.
Oil injection vs. Premix
Both variations of 2-cycle oil are generally referred to as “Premix” in slang, however they technically are different.
Some modern bikes now use oil injection systems that automatically mix your oil and fuel together as they enter the combustion chamber. This is convenient because the mixture ratio is progressive, and doesn’t require you to decide on the specific ratio.
True Premix is more common in early model two-strokes. This requires you to mix the fuel and oil manually before pouring it into your gas tank. Each bike will recommend a specific ratio of oil to fuel. Refer to your owners manual to be sure of your bikes required ratio. A safe standard is 32:1, however, some modern bikes recommend much less oil.
Different types of premix:
Petroleum based-
Typically you will want to steers clear of 100% petroleum based premixes. The reason for this is that petroleum based premixes are made from the same base as the fuel that you mix it into. This causes the premix to escentially become part of your fuel and causes it to have minimal lubricating benefits. I don’t recommend ever using a 100% petroleum based mix in your motorcycle.
Castor based-
Castor oil is what all the old timers swear by, and in their generation it was the best oil to use for the longevity of your engine. Early model two-strokes were a simple and the exhaust port was a fixed size with no moving parts allowing castor oil to lubricate without causing any harm due to left behind residue. However, most modern two-strokes use power valves that progressively open and close your exhaust port depending on your engine RPM. This is where castor oil tends to gum up your power valves and harms your engine performance. I don’t recommend using a full castor premix in your modern two-stroke engine, but if you like to keep it old school and want as much lubrication as possible many people still run Klotz Benol 2-cycle Castor as it has been altered to have less build up than traditional Castor oils.
Synthetic-
Full synthetic premix is my personal favorite, however, it does come with some risk if you aren’t very experienced with motorcycle jetting and mixture ratios. Synthetic premixes provide the best lubrication, when used in the correct ratios. They also do not gum up your power valves as the oil burns cleanly not leaving behind films and residue like a Castor oil does. Since they do not leave behind the lubricating film and residue, like a castor oil does, there is risk to your engine if you run the engine too hot or have your jetting too lean. I recommend full synthetic premix if you’re experienced and keep your jetting optimal. Your engine will run clean and have the best performance. I have been using Honda HP2 premix for years and love the results. Some other ones to consider are Motorex Cross Power 2T and Spectro SX Platinum.
Castor/Synthetic blend-
Castor/Synthetic blends are the most popular choice among riders today. This is what I recommend for someone new to two-strokes. This formula combines the best of both worlds by providing clean burning full synthetic lubricating qualities that don’t gum up your power valves, and also leaving behind a little bit of Castor protection if your engine gets too hot or runs lean. Since it does have Castor blended into it there is still a little bit of residue left behind on power valves, but it is minimal, and provides good insurance that you don’t harm your engine. If you decide to use this popular two-stroke premix I recommend Maxima Castor 927. Keep in mind this premix can separate from your fuel in cold conditions so be sure it is well blended before starting your engine on a cold day.
Conclusion-
The best two options for modern two-stroke motorcycles are full synthetic premixes if you’re an experienced motorcyclist. Synthetic Castor blend is the choice if you’re new to motorcycles as it allows more protection against a wrongly jetted motorcycle.