Funky with the oil? Nope, 100% pure degummed, first press castor oil is superior to any 2 stroke oil (conventional or synthetic) with respect to lubricity, sheer strength, film strength, activity under extreme pressure, better than anything at high temps, and when it does flash at extremely high temps, it forms a dry lubricant that still lubes the engine. The only drawback is that it does build up a little more varnish on engine internals and plug than conventional and/or synthetic oil but that is a small price to pay for superior engine protection. With that said, I have yet to "devarnish" an engine or a plug because a quality castor oil (degummed, first press) doesn't do this as much. The issue with the oil not mixing with gasoline is nothing I've observed. I mix my fuel in small batches of a gallon or less at a time and shake the mix real well. Using 100% castor oil is really not needed. If you add 4 oz of oil per gallon, 1 to 2 oz of that being castor will HELP a lot! I ride my bikes a lot off road at full throttle in a very low gear 34tooth mega gear, and non-stock gearing on my jackshaft kit so that my bikes can climb any hill that Colorado has to offer. High engine loads at high rpms with slow forward movement (less cooling over engine head) has caused my exhaust pipes to turn cherry red at the header while riding in 85deg + weather with no engine seizure or premature engine wear/failure.
Here is a discussion (rebuttal) by someone who who runs castor and disagrees about what another author about 2 stroke oils said about castor:
One of the best “general” information articles about current two stroke oils is at the link below. While this article was originally authored with a specific view towards two-stroke personal watercraft oils, we consider the info to be very current and well written … it is “highly recommended reading” for any vintage two-stroke owner.
For those not wanting to muddle through the entire text, we consider the two excerpts below to be far and away the most important with respect to vintage two strokes.
Castor Based Oils
Mr. Robert Verret wrote in http://www.sea-doo.net/techarticles/oil/oil.htm:
I mentioned a third category of base oils earlier, vegetable or Castor (not Castrol, that’s a manufacturer) bean oil. This oil is derived from pressing oil out of castor beans and distilling it. ‘Bean Oil’ as it is often referred to, has some very unique characteristics; some very good, others not so good. The good is that it is an excellent lubricant. It seeks out hot spots in the engine and clings to those hot surfaces much better than petroleum type oils. The bad is that it does not mix with gasoline easily and it burns ‘dirty’ (excessive carbon/varnish deposits). In the early 70s, before power valves were used, castor bean oil was very popular in racing 2-strokes. Now that power valves are common and we have improved petroleum and synthetic oils, castor bean oil is seldom used anymore. Several companies still market it in the form of a degummed castor oil for racing applications only. It should be avoided for recreational use unless you enjoy tearing your engine down for a top end cleanup fairly often. Several manufacturers formulate their oil with castor bean oil as an additive (antiwear agent) rather than base oil. They blend it with their petroleum and synthetic base oils. When castor bean oil burns, it has an unmistakable ‘sweet’ smell. (end of excerpt)
Like the author of the above text (Mr. Robert Verret) we too have been involved with two-strokes for 30+ years, and we have also spoken with many well educated and well informed folks in the lubrication business. All the experienced and reputable folks we have ever spoken to agreed on the basic qualities of Castor oils. That is, castor bean based oils are not particularly clean burning, do not mix homogonously with virtually any fuel, and are very expensive to manufacture …. But they offer a film strength and lubrication quality that is not matched by any other oil…. Period.
Like Mr. Verret, we also understand that many folks get very emotional about the particular oil brand they use. For us, choosing a 2-stroke oil is all about the science and results … emotion doesn’t matter. For air cooled two-strokes being run at high rpms and high loads, there is no better choice than a castor based oil. During our stint of running the DG Performance race team from 1975-1979, we ran ONLY 20:1 Castrol “R” in every Team DG machine raced out of our shop. The sheer film strength of the bean oil allowed us to run tighter than normal piston clearances, and thereby netting better performance and long term piston life (as a result of less piston "rattling” in the bore).
Castrol “R” was certainly a bit dirty, but it was the best stuff of the day. Of the castor bean oils currently available, we prefer Maxima 927. While it is not “perfectly clean” we have found it to run cleaner than any other bean oil we have used (and we have used plenty). In addition, the film strength of “927” is every bit as good as the Castrol “R” of the 1970’s, with a lot less mess.
In 2010, we built and road raced two 1970 Kawasaki 350 Bighorn Production Class enduros in the western AHRMA road race events. We ran these machines on a 20:1 mix of “927” and 105 octane race gas. While stock Bighorns redline at 6000rpm, ours turned 8500rpm and ran a bit over 100mph. At the Willow Springs track in Southern California, we lapped at 1:52 (an average speed of 80mph). At Willow, our Bighorns were constantly at peak rpm in 4th & 5th gear for every moment of each 15 minute practice session and race. Our race weekend entailed 4 outings for each of 2 days … a total of 120 operating minutes at peak rpm in high gear (per machine) … with not one mechanical issue at all. We respectfully submit that there isn’t any way to subject a vintage two stroke to any more intense abuse than this, and we feel that the lubrication abilities of the Maxima “927” were a fundamental contributor to our weekends of trouble free racing.
After our race season was done, we fitted our Bighorns with street-lighting, and ran the exact same machines on the 100 mile Hansen Dam classic motorcycle ride north of Los Angeles. At this event, we ran the Bighorns on a 40:1 mix of “927” and 91 octane pump gas (most of the ride was done at 3000-5000rpm). The bikes never put out any visible smoke (except at long stop lights) and never came close to fouling a spark plug.
Despite all this very positive experience with a Castor based oil, we openly acknowledge that Castor oils “ARE NOT” necessarily the best choice for all vintage two-stroke applications. Robert Verret’s excerpt below explains that.