Selecting The Appropriate Engine Oil

Last update: 3 Feb 2002

Which is the best oil product for my motorcycle? There is a continuous hype about the hi-tech modern oils and their critical role on the reliable operation of modern engines. However, it is very difficult to make comparisons between different oil products, unless you have data derived from independent measurements. Is there anybody who disassembled his bike, after a prolonged use of the same oil brand, in order to check for wear and deposits? Feel, colour and blackening rate isn't of any importance. Let's get serious. The only useful criteria for selecting an oil are, I think, the good name of the oil manufacturer and the following things:

1. API specification.. HONDA recommends SE (!) or SF or SG oils. As you see, there is not anything critical here, since even an old specification , like SE, is acceptable. In a relevant article by V. Karahalios on the Greek magazine MOTO, it was written that other Japanese motorcycle manufacturers strongly discourage using of API-SJ/SH oils. I don't know what is HONDA official point view (but look at the end of this page).
2. Viscosity index (S.A.E.) must conform to the climate. A SAE 15W50 viscosity is suitable for mild climate countries like Greece (however, in a 30-45 ^oC hot summer, an 20W50 oil performs better). In "XL600V User's Manual", there is a useful picture for selecting viscosity versus environment temperature. Better avoid wide viscosity range oils, like 5W50 or 0W50. Their initial viscosity is the first (smallest one) number of their characterisation. As it happens with all of the multi-viscosity oils, they use polymers in order to reduce the tendency to loose viscosity under higher temperatures. In the hot Greek summer, a 5W50 oil would be definitely worse than a 20W50 oil.
3. Desirable interval between oil changes. HONDA recommends 12000Km and (in absence of any detailed reference I concluded) mineral oil of API-SE/SF/SG. Is this long interval an exaggeration?. My personal opinion is that we must shorten this interval to, say, 6000 Km even when using a semi-synthetic oil. Of course, another exaggeration takes place if one uses an expensive fully synthetic motor oil on his Transalp and changes it every 3000Km. In that case, he simply takes out money of his pocket and multiplies the environmental pollution. Always remember that TA is definitely not a high performance motorcycle.
4. Be sure that it doesn't contain excessive amount of friction modifiers (as in some motor oils for modern cars). It won't harm the motor, but the clutch will slip thus making the motorcycle unusable.

Regarding to oils for the Transalp motor, here is what HONDA Germany says (from a conversation with Detlev (Deti) Mueller):

"I just talked to another technical support guy of Honda Germany, and he said, "Choose your oil according to manual, which reads 15W40, 20W40 or something like that, and API SF/SG or better." I argued with all that well known stuff - gear, clutch etc -, but he said, no problem at all. He also told me, that they are requiring *motor* oil, not special *motorcycle* oil, and that thus also SJ/SH specification would be ok. Also, he didn't know about any problems when using that oil. Concerning 0Wxx or 5Wxx oils, he strongly did not recommend that stuff."

"Motor oil" means any general purpose 4T engine oil (e.g. oils for cars).