So is the spec synthetic Motul or the VP RS-7 that is known to cause problems?
If the latter then effectively we don’t have a synthetic oil spec’d.
that is a shame as there is no reason not to run synthetic in our eninges. they simply don’t get hot enough to require castor as compared to synthetics. I have decades of 2 cycle esperience with engines that turn 20-25,000 rpm and run much hotter than kart engines. A blend of 80% syn with 20% castor is perfectt. but it seems only Klotz offers this.
Castor is gummy and will varnish more than synthetic by its very chemical composition.
I’d really like to have a synthetic oil to run but if I can only pick RS7, with known problems then I am forced to gumm up my engine. 😥