XT500 and synthetic oil

[brendand]

Recently obtained a 1979 XT500, with a 1980 TT500 engine block. Was an old farm bike which just took me 2 months to restore. Now that it is running like a dream, the debate of traditional to synthetic oils, has risen it's ugly head. Dealers tell me the synthetics can cause binding on the clutch plates.

Any comments?

[brent j]

I have a couple of XT/TT's I use for racing (VMX) and trail riding.

I run normal mineral oil and throw in some SLICK 50 or equivalent every year or so.

I change the oil and filter every two rides or races. I believe the teflon additives do help and change the oil regularly to keep the engines clean.

Brent

[brendand]

Brent

Thanx for the tip, but I prefer not to use PTFE additives. Tends to clog passages (See links). I think the best tip is just to replace oil more often than recommended by service manual. This ensures a clean engine and an oil that has not broken down due to heat or age.

http://www.msgroup.org/TIP043.html or http://skepdic.com/slick50.html

Any other comments welcome.

[Beyond The Pale]

I've tried many different kinds of oils in my various bikes. I have used motorcycle specific oils and several kinds of synthetic. For the last few years I have been using heavy duty diesel oils. They seem to stand up to the motorcycle engine well, are comparably inexpensive, and are universally available. In the states the largest brands are Rotella (Shell), Delo (Chevron), and Devlac (BP/Mobil).

Most any oil will work. If you use an oil designed for automobiles, they don't last very long, maybe 600-700km. The motorcycle transmission literally chews them up and they lose viscosity quickly.

[jacksmack21]

My xt550 did not like synthetic oil didn't shift right and hard to find neutral, so I switched to Rotella oil. Much better. Friend of mine had a similar out come with his xt350.

[brendand]

Thanx for the tip.Spoke to one of my clients (BP Lube Agent), and he can supply me with a BP/Castrol Vanellus C3-40, which he claims is equivilant to the Rotella 40. Hope this lasts longer than normal oil. In Namibia our ambient summer temperature is about 35 deg/cel, so normal oil breaks down after one long trip through the desert.

[brendand]

Thanx for the tip.Spoke to one of my clients (BP Lube Agent), and he can supply me with a BP/Castrol Vanellus C3-40, which he claims is equivilant to the Rotella 40. Hope this lasts longer than normal oil. In Namibia our ambient summer temperature is about 35 deg/cel, so normal oil breaks down after one long trip through the desert.

[Beyond The Pale]

The Rotella that I use is a 15W-40 viscosity. You will have no problems at 35 C. Here in the deserts of Southern California the summer temps are more like 45 C. My limit for riding is about 40C, and the Rotella has no problems at those temperatures in my air cooled XR600.

[maim]

i run amsoil 20w50 wet sump compatible sythetic oil in my xt. doesnt get as hot here. doing good for me as i mostly street run my xt350. only time i have trouble getting into neutral is when the bike is too hot from sitting in traffic.

[frankenduro]

The first question to ask about synthetic oil is "what is synthetic oil?" As a result of the Mobil/Castrol lawsuit, synthetic oil is either Group III (hydroprocessed petroleum base stock) or Group IV (polyalphaolefin (PAO) base stock). Except for premium synthetic oils, like Amsoil or Redline, almost all synthetic oils are Group III oils. Since Group III oils are just highly-refined petroleum oils, trying to distinguish synthetic oils from petroleum oils is not as clear cut as most people seem to think. Considerations such as wet clutch compatibility depend more on the types and amounts of additives, especially friction modifiers, such as molybdenum compounds, not the type of base stock. Motorcycle oils, whether "synthetic" or not, are usually MA rated and do not include friction modifiers. Motor oils for heavy duty applications (e.g., diesel trucks) usually also do not include friction modifiers. I've read that the Rotella T synthetic 5W-40 that I use would meet MA specs if not for its higher ash content. I would definitely avoid adding most additives, especially ones like PTFE, which don't belong in an engine, much less in a wet clutch. In an air-cooled engine, I'd be particularly concerned about the possibility of decomposition of fluorinated additives, like PTFE, yielding hydrofluoric acid, which is the last thing I would want in my crankcase.

The bottom line is to avoid oils containing friction modifiers (which usually have "energy conserving" on the label) in wet clutch applications and to change the oil often. I use the Rotella T synthetic 5W-40 because it's the cheapest Group III that almost meets the MA rating, which encourages me to change the oil frequently. I'd consider using Rotella T non-synthetic 15W-40, as it's even cheaper and 15W-40 uses a more viscous base stock similar to 20W-50, while 5W-40 and 10W-40 use a less viscous base stock similar to 10W-30. As you can see, after the Mobil/Castrol lawsuit, I don't put much emphasis on synthetic vs. non-synthetic.

[Dwight_Rudder]

I have a couple of XT/TT's I use for racing (VMX) and trail riding.

I run normal mineral oil and throw in some SLICK 50 or equivalent every year or so.

I change the oil and filter every two rides or races. I believe the teflon additives do help and change the oil regularly to keep the engines clean.

Brent

NEVER use Slick 50 or any slick additives with Moly or Teflon in a wet clutch engine. It will cause clutch slippage and clutch failure at best.

Could clog oil passages at worst.

A Motorcycle specific JASO MA rated synthetic oil would be fine and should not give any clutch problems.

Dwight

[brent j]

I hate to argue the point but.......

I've used teflon additives in four stroke bike engines for about 25 years.

I've never had a clutch slippage problem or failure and I've never found any trace of oil passage blockages either.

With regard to the whole subject of high perforance oils in XT/TT's, these bikes have survived for nearly 30 years and most have been abused in that time, usually running cheap oils. Us old guys buy them and ride them every few weekends at most and usually ride fairly sedately. Do we really need oil that costs $500 a litre?!.

My race bike has been dyno'd at 42 hp. I use the cheapest oil I can get (and I still put in teflon once a year) and change it and the filter after every race meeting. The bike has been raced for three years, (usually against modern bikes) still has good comp and has not been stripped. I figure I'll probably get a few more years out of it before it needs any engine work.

I know every one wants the best for their pride and joy. As kids we owned these bikes, we thrashed the living shit out of them and did stuff all maintenance. The fact that so many survive tiday is testament to a solid design.

What's the best oil for your TT? What ever you are comfortable with.

[Dwight_Rudder]

You haven't even mentioned Esters which are true man made Synthetics.

PAO can be considered synthetic as they are so altered they they can be considered such. I don't consider Group III base lubes synthetic and consider any company that markets Group III base lube as a synthetic as deceptive and unreliable.

Dwight

The first question to ask about synthetic oil is "what is synthetic oil?" As a result of the Mobil/Castrol lawsuit, synthetic oil is either Group III (hydroprocessed petroleum base stock) or Group IV (polyalphaolefin (PAO) base stock). Except for premium synthetic oils, like Amsoil or Redline, almost all synthetic oils are Group III oils. Since Group III oils are just highly-refined petroleum oils, trying to distinguish synthetic oils from petroleum oils is not as clear cut as most people seem to think. Considerations such as wet clutch compatibility depend more on the types and amounts of additives, especially friction modifiers, such as molybdenum compounds, not the type of base stock. Motorcycle oils, whether "synthetic" or not, are usually MA rated and do not include friction modifiers. Motor oils for heavy duty applications (e.g., diesel trucks) usually also do not include friction modifiers. I've read that the Rotella T synthetic 5W-40 that I use would meet MA specs if not for its higher ash content. I would definitely avoid adding most additives, especially ones like PTFE, which don't belong in an engine, much less in a wet clutch. In an air-cooled engine, I'd be particularly concerned about the possibility of decomposition of fluorinated additives, like PTFE, yielding hydrofluoric acid, which is the last thing I would want in my crankcase.

The bottom line is to avoid oils containing friction modifiers (which usually have "energy conserving" on the label) in wet clutch applications and to change the oil often. I use the Rotella T synthetic 5W-40 because it's the cheapest Group III that almost meets the MA rating, which encourages me to change the oil frequently. I'd consider using Rotella T non-synthetic 15W-40, as it's even cheaper and 15W-40 uses a more viscous base stock similar to 20W-50, while 5W-40 and 10W-40 use a less viscous base stock similar to 10W-30. As you can see, after the Mobil/Castrol lawsuit, I don't put much emphasis on synthetic vs. non-synthetic.

[Dwight_Rudder]

I have personally tried Teflon products in a wet clutch and I can attest that I had to replace my clutch after using the junk. If you haven't had a problem then you are lucky. Also why use cheap oil . Oil is cheap insurance. I for one will use the best that I can find.

Cher'o,

Dwight

[TheFrenchCanadian]

i run amsoil 20w50 wet sump compatible sythetic oil in my xt. doesnt get as hot here. doing good for me as i mostly street run my xt350. only time i have trouble getting into neutral is when the bike is too hot from sitting in traffic.

Same here. I use Amsoil in all of my 6 bikes. Never had a problem with the clutch in any of 'em and they shift waaaayy better with the synthetic. Currently I'm using Amsoil 20W50 motorcycle oil in my XT550, I change it once a year (probably about 2500Kms or so... I'd feel comfortable going up to 5000kms on it...)works good, no hassles.

TFC