I spent last night learning (the hard way) that synthetic two stroke oil containing esters are hygroscopic. Warning to everyone using this stuff, don’t just park your toys and leave them sit for extended periods with this oil inside!
All my engines get rotated at least once every 2 months and in the case of this one it has never sat longer than 4 months without being run. That said the main beatings in this engine are pitted, the crank throws have rust spots on them and even the wrist pin has a couple small pits in it. Now everything that moves will need to be replaced instead of what should have been just a top end job.
After a pressure wash I always start my bikes and make a lap around the block, but I guess I may not be revving them up enough to blow out all the water droplets in the cases and after doing some reading I found out that unlike conventional two stroke oil that would protect the metal from a little moisture, this synthetic stuff draws water in and allows the metal to rust instead of protecting it.
This set of internals has only seen Motul T2 oil and there was no sign of any of this the last time I did rings in it. I’m a little scared to peek in my Tri-Z and other dirt bike as neither have been run for over 7 months.
I plan to keep using the oil because it leaves almost no deposits on power valves and piston & ring wear is minimal compared to other oil I’ve tried, but I am going to start running the engines up to operating temperature at least once a month from now on.
Photos are coming…