Oils for Airheads

[Altritter]

The August edition of the BMWMOA ON (Owners' News) arrived a few days ago. The "Keep 'em Flying" column (about airhead maintenance) contains a narrative and Oil Analysis table on page 32 regarding oils that are best for air-cooled engines, and why.

The condensed version: Look for oils carrying the API "SG" rating for best anti-wear protection. (For our international friends, the article points out that the Japanese JAMA MA is equivalent.)

The author had 4 motorcycle oils tested. Under the criteria specified in the article all 4 tested fine. Of the four, the two Valvolines (20w50 and 10w40) were the most economical at $4.50/qt; BMW's non-synthetic 20w50 @ $7/qt was in the middle; and Mobil 1 V-Twin Synthetic at $11/qt had the top price.

Guess ya pays yer money & makes yer choices!  

In same article: A description of the consequences of accidentally putting diesel into an airhead. (In my neighborhood several stations have pumps carrying both gasoline & diesel; it can happen if one isn't careful.) Three successive teardowns of an R75/5 engine before the damage was was corrected.  [smiley=steinigung.gif] Ouch!!

[weasel01]

I know this belongs in the rants area but I thought I would chime in with the info I found out.

I love stuff like this did a TON of reseach called Castrol and others and this is what I found out.

Castrol GTX is the standard most BMW riders use and when it was originally offered it still had all the good ingrediants in it... that was up until the end of the class SG rating.

GTX no longer hold an SG rating as it is generations beyond that and is no longer reccomended by BMW nor is it reccomended by Castrol.

In fact the castrol rep said Do not use it in your air cooled bike.
Also said do not use any motor oil beyond the SG rating in your air cooled bike.

My bike wont hold synthetic without weeping it out here and there so the only non synthetic class SG motor oil found locally here it is offered by castrol and it's their 4T motorcycle oil.

Thier are other motorcyle specific oils available just not around here.

All the oils brewed specifically for air cooled motorcyles have an
SG rating and not beyond.

Of all of the SG rated oils the Golden Spectro has the highest goodness ingrediants listed.

Castrol would not give me an ingrediant list.

[Justin B.]

This thread just might live on here as long as everything presented is backed up with hard evidence, specifications, or testing.  Bummer about the GTX, I have used that stuff for over 30 years...

[Bengt_Phorqs]

Ratings are important no doubt but it's also recommended that one be consistent with the brand and grade of oil one used.  I was having a conversation with one of our process engineers earlier this week and asked him about the difference between synthetic and dyno oils.  He shot me this reply...

"Motor oil is from oil.  Synthetic oil is from oil also but check out the diffference.

Motor oil is designed to serve many different purposes within a cars engine. While the primary function is to simply lubricate all the moving parts and provide protection from wear and corrosion, it also is intended to keep the engine cool and free from small pieces of debris.
Conventional motor oils are made from crude oil which has been is pumped from the ground and then processed in a refinery to create a base oil. Additives are then mixed into the base oil to change the viscosity, protection properties and heat breakdown levels of the oil.
Synthetic oil is also created in a similar manner to conventional engine oil, using base oil combined with a series of additives. The difference lies in the fact that synthetic motor oils are created utilizing a specially "synthesized" base oil where the size of the oil molecules are all of an ideal weight and of a consistent size. While conventional motor oil, despite the refining processes, is made up of different molecule sizes which are mixed together, along with various waxes and impurities, fully synthetic oil is made to provide a much purer base oil, with less waxes and with a uniform ideal particle size to help increase the oils viscosity level. Added to this ideal base oil is a combination of more technically sophisticated additives than are used with the conventional oils."
 
So then I went to wikipedia to see what they had to say...
http://en.wikipedia.org/wiki/Synthetic_oil
Quite an informative article and now I have a better understanding of what it's all about.  

And now I'm out of characters so I'll shut up.

[weasel01]

Wax must be what keeps the dino inside my bike where as the the synth wanted out.

I should say that we are talking motor oil and my only synthetic experience was in the greabox and rear end.

From my conversation with the Castrol guy the GTX prior to 1991 or so would have still been SG rated and would have been perfect but because of more strict restrictions certian additives were cut way back or removed all together.

So GTX with a rating of SH or later would be the issue.

It was all concern for the valves.... tapped vs. rotary... I assume overhad cam style engines which are unaffected by the rating progression.

I'm sure GTX is what has been run in mine all of it's life but I've decided to stick with SG rated dino.

[Yikes]

Are the SG rated oils available at auto parts stores or do you have to get them at the cycle shops?

[weasel01]

My local Oriley's auto parts stocks the Castrol 4T 20/50 on the shelf ..it has a motorcycle on the bottle.

I did recently find a local MC shop that stocks Golden Spectro which is what I will probably end up using.

[Altritter]

Are the SG rated oils available at auto parts stores or do you have to get them at the cycle shops?

Out of curiosity, I visited my local Advance Auto Parts store (I'm sure you have them in Richmond) and checked the shelves. Advance stocks both of the Valvoline motorcycle oils (20w50 and 10w40), but in a location separate from the automotive oils. (They're included with marine and two-cycle oils, so it helps to ask.) The SAE rating is SG/SJ. (Any engineers out there who can address any discrepancies between the classifications?

[Bengt_Phorqs]

I came across "The Motor Oil Bible" while doing a search.  While I can't speak to the accuracy of the information contained, it appears to have some good information.  http://www.trustmymechanic.com/motor-oil-bible.pdf
What I took from Matt Parkhouse's article was the need for a zinc additive.  Matt has been spinning wrenches on airheads since Moby Dick was a minnow so I wouldn't dispute or argue with his opinions, but I intend to do a little more research in the matter.  I've been using Castrol GTX in my bikes for years and years and have never had an engine problem as a result of oil lubrication.  

[benita]

You can always add Zinc to the oil buy purchasing an additive like STP oil treatment for 4 cylinders.I add it to 20-50 spectro, and swear buy it