The full synthetic Valveline I referred to was an automobile oil and can be found at places like Wal-Mart or K-mart.

As far as clutch slippage, I have never heard about it till now. I did a little research on synthetics before changing but never read anything about harming a wet clutch. I haven’t done much riding since switching but I might go to Glamis this weekend so we’ll see.

 

Guys, whatever you use, don't use car oil. Motorcycle oil is formulated to work with a wet clutch system. Car much more slippery than motorcycle oil. With motorcycles, you need the oil to lubricate as much as possible without making the clutch disks slip. Cars just need no friction and the oils are designed accordingly. Oil is not oil. Stick with the tried & true petroleum based MOTORCYCLE stuff and just change it often. You go using the car stuff you get on sale at Walmart for your ATV and you could fry your clutch disks. One application of synthetic oil impregnates the pourous clutch disks. You can't even scrub it out. If you have any HP at all you could spin the clutch then it doesn't matter if you have 100 HP because it never gets to the tires.

Something to think about.

 

I'm going to go out on a limb here and open myself up for flames.... Please excuse my tone, but I have posted similar information on several occasions. Everyone needs to do a little research. I've heard about every myth there is about synthetics in this thread.

1.) Synthetic oils do not "cause" clutch slippage. I have run them for years, never a problem. If anyone is interested in how my machines are ridden, I direct you to the link at the bottom of this post. I currently run Mobil1 15w50 in my 400EX, no problem. It's been to the dunes, probably the roughest environment there is to clutches, it is also raced, still no problem. There is some concern about oils with "friction modifiers", but those can be found in both synthetic and conventional oils.

2.) In independent testing "motorcycle" oils fail to show properties that make them more desirable for wet clutches and transmissions. In fact, in many cases they don't perform quite as well as automotive conventional oils. These tests are on the web, look them up. Motorcycle oils are marketed by motorcycle manufacturers, not made by them (with the possible exception of Honda, I have heard that they may refine their own), they will tell you what you want to hear to get you to buy them, that's the whole theory behind "marketing". I have never heard hard facts as to why they are better, only marketing rhetoric telling me they are more resistant to "shearing", etc. Tell me why, if you can.

3.) Synthetic oils are not more thin, less sticky, or more slippery than conventional oils, their weights are measured the same as conventional oils, they do, however, exhibit better extreme cold pumpability and better resistance to thermal breakdown, and better film strengh but this has nothing to do with them being "more thin" than conventional oil. I can only guess that the Web-cam folks are blinded by myths that they have heard. I have never heard a large, "real" camshaft manufacturer make such statements.

4.) Synthetic blends were developed to meet a price point, not offer the best lubricitive properties.

5.) Castrol full synthetic is not truely a full synthetic. It is a highly refined level 3 hydrocracked mineral oil. Better than conventional oil, but not truly a synthetic. Mobil1 is a level 4 oil that actually has 3 blends of synthetic base stock, PAO (polyalphaolefin), polyolesters, and diesters. Redline and Motul are two examples of Level 5 Ester (polyolester, I believe) based oils. Level 5 oils are obviously the most expensive. Use this data to do a search on the web, find the good and bad points about these base stocks, there's tons of good info out there just waiting to be read.

6.) Synthetic oil will not cause your cam to go flat. I recently pulled apart my 350X (due to sucking some dirt several years ago, long story) which ran a good portion of it's life on synthetic, the cam was in excellent condition. Do any of you really think if this were the case that the synthetic oil manufacturers would be able to stay in business? Don't you think if they caused wet clutches to slip, the corporate lawyers would make them put some sort of "Don't use in motorcycles" disclaimer on the bottle?

7.) Check with the sport bike enthusiasts, they run wet clutches, 14,000 RPM engines with over 100HP, many of them use automotive synthetic without trouble. There is lots of documentation of this on the web as well.

8.) I use the Mobil1 not because it's the best, there are better out there, but because it is very good, easily obtainable, and can be found at a descent price at Walmart.

I have done the tests and research, these are my findings, dispute if you must, but please have facts and research to back up your statements.

 

Gabe...
So all in all, your saying you use Mobil 1 10w-40 synthetic Automobile oil, NOT motorcycle oil. Is this correct ?? Or did I miss something!! I have been to both Mobil1 and Amsoil, and they both have motorcycle oil that "they" say works fine with wet clutches. Are there Auto oil going to work the same ??

Thanks for the help Gabe !!!
Jason

 

The Mobil1 I have been using is automotive 15w50. I don't believe it has any "friction modifiers" and contains no viscosity index improver. I have found that lighter weight oils break down quickly in the air cooled 400EX. I don't have access to a 300EX to try, based on my past experience I would use the 15w50 in it as well.

If you have access to the motorcycle version of AMSOil (also a level 4 PAO oil) or Mobil1, and it makes you feel better, use it, otherwise I see no problem (nor have I had any trouble) with using the automotive version.

 

THANK YOU! That pretty much sums up what I found when researching before I switched. In all my extensive reading the only down side I could find to synthetic is the price and in order to maintain your warranty you still have to change it the same, even though it last a lot longer.

DON’T forget to break in a new engine with good old dinosaur juice first.