10W-40 or 20W-40/50?

[themoudie]

Agree with Smudge.

Jap motors with plain bearing surfaces rely on oil film integraty and pressure to maintain that film so 10W-40W semi-synthetic French oil for the R*****t trade at £20-00+VAT for 20litres, all above board, does the Toyota CarinaE (5K), the Fiat Punto 55 SX, Honda Bros 400 (2K), Yamaha SRX600 (1.5K) oil change interval in brackets with a filter every other change.

Morini 125 is getting bog standard Halfords 20W-50W every (1K) and Duke single got straight 40W every (1K) most of the time, all balls and rollers with few plain bearings requiring oil volume and flow rather than pressure to maintain oil film. Also marginal oil filtering in these motors, coarse nylon nets at best, not even quality British felt!

Witty Ducati used Duckhams 'Green' 20W-50W, in all his Dukes when racing in the mid '70's. Changed after every meeting, but with no extra filters and motors to the red line or valve float when required. Never ran a big end to my knowledge and was a good sponsor at the time.

"Warm the motor through first" is another must with big pistons and often little lateral supporting skirt! Jethro!!!!!!!! ;-)

Chuckle, Goodnight.

So far, so good, I'll not say more unless I annoy my fairy.

[guest27]

Ahh but you are in South Wales and the whole place is swimming in lard and dripping from all the deep fried salads and battered muesli - bit posher in Cardiff than out here where we have deep fried lard in double batter.

R

[bikeseamus]

In the USA, the EPA has essentially outlawed phosphorous and zinc as an oil additive if the vehicle has a catalytic converter, so our car oils are garbage. Even Mobil 1 has a separate motorcycle oil that contains these wonderful additives. They make your engine last longer by having molecular sheer resistance and longer string molecules that resist shearing a tranny generates.
                     Our "friction modified" oils are worse yet... very short string molecules with very little cling that allow pistons and other parts to be slipprier for slightly better fuel mileage but dreadful film strength and low molecular shear resistance.

  My friend designs and develops oil for a major oil company, and has done so for about 30 years. He has a mass spectograph, an explosion room for blowing up engines, and loves his job. He is also an avid bike rider and hot rod builder, and got his doctorate in mechanical engineering from a fine University. It is an understatement to say he understands motor oils.

  I talk to him and listen to the latest on oils from him, read no rumors,believe no advertisers.

Everything I said about oils applies to oils available to us here in the USA. As for those available to you, I don't know, but all the bike shops here see mechanical failures because of people using car oils in their bikes, and our owners manuals state specifically that your warranty will be voided if you use car oil.

 All the rules changes about ten years ago when the Environmental Protection Agency got into the oil business. In the old days, all the good oils stated very clearly on the back that they were suitable for 4 stroke motorcycles. Now none of them have the MA rating, and very few have the JASO rating, which is a very stringent standard in Japan for valve wear testing.

  All the 4 stroke bike oils have both...MA and JASO.  That is as good as it gets.   Thought I might clear this up a bit.

  As for weights, if a bike maker recommends a specific weight, it is because the engine clearances were engineered and tested for that weight. You can run thinner oil and the engine won't blow up, but your oil pressures will be below the engineered specs and generally your film strengths will be lower, and your engine will wear faster.

 I would be curious whether Castrol makes a motorcycle specific oil for you guys. Over here, they have several motorcycle specific oils, but NONE of their car oils have the MA or JASO ratings. They aren't good enough for the specification.

[peterj]

Aren't oils fun?

I hadn't heard of JASO or MA before so a I did a bit of searching. I found this info here

http://motorcycleinfo.calsci.com/Oils1.html

"JASO certified Oil
Another institute that certifies oils is called the Japanese Automotive Standards Organization, JASO. One wonders why this Japanese organization has an English name. . . In any case, they have two classifications for motorcycles, "MA" and "MB." MA is the one you want. MB is like the API SL category, it's got all those nasty friction reducing chemicals that may scare your clutch into misbehaving. Again, there is an official JASO seal if the oil has been independently tested. The seal is a rectangle; in the upper quarter of the rectangle will be a serial number, and the lower three quarters will just have the letters MA. If the oil manufacturer did their own testing, instead you'll see just words like "Meets or exceeds JASO MA standards."

Some manufacturers recommend JASO-MA certified oil. AMSOil and Golden Spectro are JASO-MA certified. Some people consider this important. Interestingly, although Honda recommends a JASO-MA oil, Honda oil is not JASO-MA certified. Mostly JASO-MA is pretty much equivalent to SH. In fact, the JASO spec is mostly a reaction to the decrease in zinc-phosphates in SJ and SL oils, and the added molybdenum disulphide in energy conserving oils. Personally, I don't care about JASO standards - they're really not on my radar. "



The rest of the article was interesting. I already knew that using any API spec "higher" than SH was a no-no due to the reduction in phosphates (from press releases from Yamaha as well as forums etc), but as I've had no problem finding SH in Australia it hasn't really been an issue for me.

The author makes a good case for using suitable grades of diesel spec API CI-4 plus, which I find an interesting alternative to paying so much more, just so the same spec oil comes in a bottle with the word motorcycle on it............

All that said, if I wasn't interested in trying to add life to my SRX fifth gear, I'd still be quite happy with the cheapest SF - SH 20/50 I could find. I drop it every 1500 miles or so (the oil that is).