K series? My 1st Yamaha blew its piston rings on the 1st day. Shit happens -- Steve Parry http://www.gwynfryn.co.uk http://www.arrivedeprived.org.uk/ K100RS SE F650 (not forgetting the SK90PY)
Fully synth is more detergent than normal dead dino oil, this is good in the winter when increased blow by and water content are about. Run an RS125 on mineral and see how long it lasts.
Muck emerged from their own little world to say I don't believe the first part and can't fathom the 2nd part of that sentence. As synth lubes are more robust they are likely to contain fewer additives. One of the reasons that mineral oils do not make good high performance oils is the level of additives required to stop them breaking down under high stress. There comes a point when the volume of additives seriously reduces the lubricating properties. As I said above, synth oils have fewer additives. You get more lube per ml which may be even more important for a 2 stroke.
Simon Atkinson says... I ran my second one on whatever Honda UK put in it whenever it went back to Power Road for new cams and tensioners. I never had to change the oil in that bike, because in the 18 months I owned it, it spent no longer than 2 weeks at a time in my hands before attempting to destroy itself again.
I remember you telling the tale. It was a badly designed engine, there is no doubt about that, and lots of people had problems with them. I knew about the problems when I bought mine (for the right money) and I knew that running on fully synth oil and not letting it tickover when cold would alleviate the problems. Mine was still fine when I chopped it in for the VTR1000.
Think about an engine being cold and having to warm up, then you'll understand. You forgot about stuff like viscosity stability and film strength. Yeh I know, plus my above comment.
