27-10-11, 04:14 PM
(26-10-11, 08:30 PM)Major Rant link Wrote: Based on what evidence ? :pokefun
Repost my text from old yuku forum:Motorcycle (vs car) engine is different in several ways:1) Clutch is in the same oil, wet clutch.2) More rpms. This puts tension on camshaft. Smaller surface takes more pressure per square inch in motorcycle.If going for auto oils, I was told not to go above SG specification semi-synthetic oils. If using auto full synth, or any above API SG, then clutch slippage is to be expected. Like you said, difference in price is nowhere near the risk taken.Silkolene semi-synth COMP 4 10w40 goes for around 7.5 e per litre here. That is what 2 oil experts recommended and agreed upon for FZS engine. One of them also recommended Motul, but said Silkolene is cheaper and almost just as good.One more thing. They also said that many oil companies sell auto oil as motor oil - which means their oil, even motorcycle specific stuff, is bad. Didn't want to say which ones, but said:"Bad stuff isn't alway cheap.Good stuff is never cheap."What they did want to say are companies who do not pack auto oil an whose motorcycle oil is at least decent. Motul, Mobile (Fuchs), Silkolene, Bel Ray are the mentioned ones I can remember. Doesn't mean some other are not good, but these were "approved" by them.What I fail to understand is how FZS engine can not benefit from full synthetic oil. From what I learned, full synth can give 1-2 k kms longer change intervals and somewhat better protection.They also said to stick to 5000 km change for town use, and 6-7 k km change for traveling. However, they said this goes for Serbia only (our petrol has a lot of sulphur - bad quality fuel).
If I had 2 new motorcylces, I would gladly do the testing myself. Ride one on car, the other on decen motorcycle specific oil. Then, after some 50.000 kms, perhaps I could come to a clonclusion. I believe that car oil could be as good, but price difference is just not worth the risk for me.
Coming from an experienced mechanic I know (and trust): Motul and Repsol are oils which never made problems for any bike.
Most things done in a hurry need to be done again - patiently.