By and large these new oils have a lot to offer for karters of every level. They have outstanding lubrication properties, they are highly soluble in both gasoline and methanol, and that solubility is not temperature sensitive, and they are exceptionally clean burning. That does not mean that every synthetic product can do everything it promises. We’ve heard some fairly outrageous claims and tested dozens of products. The good ones are really very good, but there is also plenty of “snake oil” out there.
(My favorite was the super lube additive that the salesman claimed was the product of Soviet military technology. Knowing what we now know about the now-defunct Soviet Empire, I’m not sure I’d view that claim as a positive sales strategy.) But if you stick with one of the top brand-name synthetic oils, you’ll likely be very happy with the performance.
The cleaner burning properties of these synthetics mean that the ritual cleaning of pistons and rings that is part of the castor- based world is a thing of the past. Synthetic oil users also are spared the daily hassle of scrapping built-up carbon from the piston crown and the combustion chamber just to ensure passing the cc test in post-race tech.
So how is a karter to decide which oil is right for his application? First of all, ask your engine builder/tuner. Assuming the track or organization you race with doesn’t dictate a spec oil, complying with the engine builder’s wishes will usually be the best choice. Certainly if you race in cold conditions you’ll want to think twice about using castor-based oils. And if you’re not too hot on doing lots of maintenance at the track between races, the synthetic products are an attractive choice. On the other hand, if you’ve maxed out every other element of your engine performance package, lots of top-flight tuners will tell you that you can get just a bit more by using castor. This is particularly true of air-cooled engines. The water-cooled 2 cycles offer some unique considerations, oil-wise. But the air-cooled engines will usually crank out just a bit more on castor-based lubes.
I’m sure I’ll hear from synthetic oil manufacturers, dealers, and proponents of all stripes that I obviously don’t know what I’m talking about. They’ll insist that, if you’ll only use it according to their instructions, if you’ll only build and tune your engine to their specifications, if you’ll only drive your kart the way they think you ought to, their oil will outperform anything else available. They might be right. But in my experience, most karters are unwilling or unable to redesign their entire engine program to accommodate some hoped-for oil performance increase