Years ago (in the 80’s) regulations started requiring that zinc levels in oils where reduced due to the fact zinc was destructive to emissions systems and this forced all oil manufacturers to start scrambling for replacements. Adding a bunch of zddp is ancient technology and was never popular with European oil manufacturers in the first place, so even back when it was the only wear additive used in the US they used just the minimal amount of zddp to get by and it was used mainly as an anti-oxidant. This gave Liqui Moly an advantage when zddp levels had to be reduced. Another thing to keep in mind is that it’s been over 30 years since zddp’s where regulated and believe it or not, in that time we have been able to develop newer high tech additives that are able to protect engines in the same way or better than zddp. Air cooled engines are unique and we have developed engine oils with for years with these engines in mind. In an air cooled engine it’s not only cam lifter protection you have to worry about but more importantly removing heat and preventing hot spots. Zddp does not add to an oils ability to remove heat at all. What’s more important regarding heat removal is the ability of the oil to stay on a surface long enough to “soak” up the heat and then transport it to an oil cooler and/or oil pan. When we recommend an oil for specific bike/engine combination you can safely assume that we have designed the oil with the above specifics in mind.