i agree, nerd alert

 

Some of what I have read in this thread is bothering me It doesn't match the information I have collected on oil. "Energy conserving" is assigned to 30 weight oils because it takes less h.p. to pump the lighter oil. 40w causes the oil pump to work harder to pump it but will give you better protection at higher rpm. That is why race cars uses 50w. Never the less a 40w is probably the better choice because of the hotter temps the air cooled engines run and the higher rpms on the water cooled ones. Try to use a higher number before the "w" (such aas 15w40 instead of 10w40). Polymers are added to give the oil the cold pumpability. It takes more polymers to get to 10 than to get to 15. Polymers are not good ;ubricants and take the place of lube so the less you can get by with the better off you are. If I could find a high quality oil that was a straight 40 weight I would use it.
I have been told that using a synthetic in a wet clutch motor isn't a good idea either. It is slipperier than even moly and will cause clutch slippage. This has proven to be true in our dirt bikes. I would think it would be even worse in quads because there is less slippage in the tires placing more torque on the clutches. Educate me on the use of synthetic oil on these motors because I like to use it wher ever possible.

 

Honda recommends HP4, a synthetic/petrolium blend for its manual clutch bikes, so synthetic is ok there. Or HP4M, with moly for the engine (not transmission) of the 450R, which has a split case.

It however does NOT recommend synthetic for its autoclutch bikes. GN4 is recommended for those.

 

For some reason, I find that amusing. Kinda made me laugh and all. Well, not really "all" but I did laugh.

 

Blends are only ~ 25% syn. I would be cautious about taking the acceptance of a blend to mean a 100% synthetic (especially like Amsoil with a REAL synthetic base stock) as acceptable.

How about some of those oils that are specifically advertised for four stroke motorcycles (mostly for the Harley crowd)? Some of those street bikes have a single oil supply for engine and tranny.

 

It is partially true that 30 weight oils and under are energy conserving because of having a lower weight. There are at least two factors involved in the API Energy Conserving rating. One being pumpability (which also relates to resistance on the crank, as it splashes through the oil), and the other being additives which make the oil have less friction. Generally speaking, all oils that are energy conserving are under 30 weight, and have Moly.

In either case, most energy conserving oils are not good for most bikes. 30 weight oils are too light for hotter summertime temperatures, because they thin out too much in air cooled bikes, and moly isn't good for wet clutches. If, however, you are running your ATV in the winter time, a 30 weight oil may actually be better for you. It really depends on what the winter rating is...like 5w-30 for example, would offer a 5 weight at freezing. This is a good thing, because it will still flow at the colder temperature when the engine is first started up. Then, since the ambient temperature is freezing, the air cooled engine will not be allowed to reach the same operating temperature that it would in the summer, so the 30 weight would actually be okay to run.

Now, as far as synthetic oil goes, it is a common misconception that synthetic oils are "slipperier" than conventional oils. This is not neccessarily true. Synthetic oils are designed for specific applications, and can be made thicker or thinner depending on how they are designed. This only affects viscosity, not the frictional properties of the oil. The only way to decrease the friction (make the oil slipperier) is to add things like Moly or ZDDP.

The truth about synthetic oils, is that the oil molecules are MUCH stronger, last longer, and can maintain their "weight" rating over a broader range of temperatures without the use of polymers. A fully synthetic oil that is 5w-40 would last at least twice as long as a conventional 5w-40, because it doesn't need nearly as many (if any at all) polymers to maintain that rating.

I would be carefull running a straight 40 weight oil in your engine, because at temperatures under about 80 degrees (F), it will offer very little protection at startup. Racecar drivers run single weight oils because they will last longer than multi-grade oils (due to the polymers you mentioned). However, most races are in very warm weather, the racers VERY carfully warm up their engines, and then run those engines to their redline constantly...then they completely rebuild their engine.

Most of us ride in a variety of temperatures, and rarely give our bikes more than about 30 seconds to warm up. If you were to run straight 40 weight in your engine in 50 degree weather, expect some engine wear durring startup. If you ONLY run your engine when the temp is above 75-80 degrees, straight 40 weight might be better for you. However, I'd still recommed 20W50, just to make your engine happier both at startup, and at the higher temps.

 

Most of what you are saying matches my info. Only thing different is the "slippery" question about synthetics. All my info indicates that they are superior in protection against wear when compared to conventional oils. We don't run engines long enough to prove that but we have had problems with dirt bike clutches slipping when using synthetic. Switching to conventional or, better, oil blended specifically for 2 stroke trannies, stopped the slipping.
Ocassionally I forget that I am talking to people all over the country when I talk about oil weights. Temp. isn't a factor for me because I'm in the deep south where it may get to 30 (and I don't go quad riding). Actually 40w was really a comparison. I can't find any good 40w. We do run 20w50 in one of our race engines. My personal preference is 15W40 for most engines. The info I've picked up in this thread has made up my mind what I will run in my quads. Thanks.
Some of you guys sound like you know your oils pretty good. Do you know what a Tribologist is?

 

I used GN4 for the first few oil changes, then got fed up with paying twice as much for what was probably no better oil than the Castrol Grand Prix 10w40 I'm using now. I used the same stuff for years in motorcycle engines, with zero problems. I'd like to switch to a synthetic, but I'm not sure changing oil types is a good idea in an older engine.

 

Synthetics, and commercial rated oils contain more and better detergents than standard conventional oils. An older engine that hasn't seen regular oil changes, or has had low quality oils used, will have lots of deposits around seals that have cracked or have become porus. Use of a high quality synthetic or commercially rated oil will remove these deposits, and CAN cause your engine to start leaking.

So I guess if you have oil leaks you should just stop changing your oil altogether, and let the engine plug it's own holes... [img]i/expressions/face-icon-small-happy.gif[/img] j/k

 

LOL! We call that "weening" the engine.