Interesting experience with synthetic oil...

[TeeCat]

Hi, troop...

Last oil change, I had tried a couple quarts of Valvoline 4-stroke motorcycle oil (dino) in 20W-50, but wanted to go to thinner oil in case I ride any this winter; the 20W-50 is too hard to kick, and may tear my sump strainer, I feared. So, I went with some Valvoline 10W-40 this time. It's motorcycle oil and designed for wet clutches, but all they had was full synthetic. I have never run that before but thought I'd try it, and if I didn't like it for performance reasons, it will have cost me about $16.00 and no harm done.

Well, long story short, the bike seems to really like it, just based on two local outings of about an hour each, in 60-ish F temps. Shifting seems excellent, no discernible clutch slippage, etc. But here's the one thing I really noticed:

I run a single Mikuni VM with a knurled idle speed screw. It does have a slot for a screw driver, but I like it because I can use my fingers to dial in my cold and hot idle easily as the bike warms. Well, this is a very precise thing with my bike. She has "rules", and you must learn and live by the "rules", or you will be reminded of the "rules". The difference between her cold and hot idle is exactly 3/4 turn of that screw, and at warm idle, the slot is horizontal. Well, with the synthetic, I noticed that the warm idle is a few hundred rpm higher, and I have to back the screw out about another 1/8th turn to get her right at 1200 rpm. I wonder if this is a consequence of reduced friction? I don't think the ambient temp is a factor, and this screw setting seems to be a "rule" with her. I don't think it's coincidence.

Very interesting!

TC

 

[Max Midnight]

...I have to back the screw out about another 1/8th turn to get her right at 1200 rpm. I wonder if this is a consequence of reduced friction? I don't think the ambient temp is a factor, and this screw setting seems to be a "rule" with her.

Ambient temperature may influence tick-over during the warm-up but once at operating temperature I agree with your comment.

The lower viscosity oil should cause less drag within the motor therefore will affect the tick-over.
I would also expect to see a slight reduction in fuel consumption.

 

[TeeCat]

Max, it stands to reason, I think. Now, that said, one might worry about clutch slippage due to reduced drag, but there seems to be none at all. Evidently, it is the additives in automotive synthetic oils that can potentially cause slippage, but the synthetics designed for motorcycle wet clutch applications apparently lack those suspect additives.

Anyway, more road testing, weather permitting. But again, this is Valvoline 4T 4-Stroke Motorcycle Oil, full synthetic, 10W-40, for wet clutch applications. It also comes in 20W-50. The weight might be a factor as well, but I'll wager it's more than likely the lubricating properties, since she is used to dino oil.

But... she seems to like it. And when she likes it, you try not to argue, right?

TC

 

[CDNTX650]

i have a bunch of amsoil 10-40 left from my ducati, so i run it in the xs for fall and spring, sure makes the shifting nicer. Think ill keep running synth in it.

 

[Grinder]

used amsoil 20w50 cycle oil all summer, 3K miles, no problems.

 

[1974jh5]

So does synthetic help with getting the darn thing in neutral at a stoplight? I'm running Castrol GTX and it's a bear to get in neutral if the bike's not moving. Lots of older bikes were that way and I'm used to grabbing neutral just before coming to a stop, but if true motorcycle synthetic would improve that I'd probably change.

 

[TeeCat]

So does synthetic help with getting the darn thing in neutral at a stoplight? I'm running Castrol GTX and it's a bear to get in neutral if the bike's not moving. Lots of older bikes were that way and I'm used to grabbing neutral just before coming to a stop, but if true motorcycle synthetic would improve that I'd probably change.

You know, it actually might! I was able to find neutral at will on several occasions these past two outings since the oil change. There's still a bit of finesse involved, especially with a booted foot, but I like this stuff so far. The bike just seems very happy with it.

And yes, it's motorcycle-specific full synthetic for wet clutch applications. My bike's upshifting and downshifting between second and fifth has always been quite good, but these last two outings, I have been basically just breathing on it to shift.

TC

 

[Max Midnight]

...it is the additives in automotive synthetic oils that can potentially cause slippage, but the synthetics designed for motorcycle wet clutch applications apparently lack those suspect additives.

The weight might be a factor as well, but I'll wager it's more than likely the lubricating properties, since she is used to dino oil.

But... she seems to like it. And when she likes it, you try not to argue, right?

TC

Like many simple observations the reason is ofter quite complicated.

Whilst you may be correct about the friction modifiers in synthetic oil having a benefit, I suspect that there is a limit as to how far you can go in this direction due to the wet clutch.

We often only think of friction between sliding parts and will often forget that the engine need to power the oil pump which it turn need to force oil through the oil galleries. The thinner the oil the less energy needed to achieve this.
Another factor is that those rotating parts, such as the crankshaft, rods, gears etc. will also move through the oil. Once again, the less drag there is the less energy is lost.

It would be interesting to try some of the 20W-50 to see what difference that makes?

But as you say, the bottom line is that if the bike seems happy on it then don't worry!

 

[TeeCat]

Like many simple observations the reason is ofter quite complicated.

Whilst you may be correct about the friction modifiers in synthetic oil having a benefit, I suspect that there is a limit as to how far you can go in this direction due to the wet clutch.

We often only think of friction between sliding parts and will often forget that the engine need to power the oil pump which it turn need to force oil through the oil galleries. The thinner the oil the less energy needed to achieve this.
Another factor is that those rotating parts, such as the crankshaft, rods, gears etc. will also move through the oil. Once again, the less drag there is the less energy is lost.

It would be interesting to try some of the 20W-50 to see what difference that makes?

But as you say, the bottom line is that if the bike seems happy on it then don't worry!

Ah, the oil pump-related point is an especially good one! I had not thought about that.

I have generally been using 20W-50, but it has been dino oil. In the spring, I'll go back to that weight, but this time, likely in the full synthetic. I'll have to keep an eye on the stock at my Advance Auto and get some in 20W-50 when they get it on the shelf.

TC

 

[Paul Carr]

When I contacted one of the major oil companies who made both synthetic and semi synthetic they advised against the use of full synthetic in the XS because it had roller bearings on the crank ....


Anyone lese heard this

Paul

 

[TeeCat]

Paul I think I had heard that as well, but when I did, it I don't recall that there was any really compelling rationale attached to the argument. I'd be interested in being educated on the hard science behind such advice, though.

One thing I don't quite understand is the use of the term "full synthetic", since it's my understanding (from Valvoline's site) that even synths are made from "crude base stock".

TC

 

[1974jh5]

IIRC 'Synthetic' mostly refers to the blending process. About roller bearings: they should not have any problem with synthetics. Now, there is a problem with using synthetics on sliding surfaces such as rockers and cams and it's become a big problem in the collector car hobby.

Here's the scoop: on a 'flat tappet' cam, such as those used in older pushrod V8's and 4 cylinders, the cam does not run in an oil bath. That means at startup the cam is not lubed for a few seconds until the crank starts slinging oil at it. To combat this, the oil companies added something called ZDDP (basically very finely powdered zinc) which had the property of making the oil 'sticky' so it wouldn't run off of the camshaft quickly, this was used for many years. The EPA discovered that ZDDP would 'poison' a catalytic converter so it's been phased out. That has a lot to do with why so many new engines have roller lifter cams.

Automotive synthetics don't have ZDDP so they should not be used in older flat tappet type engines unless they have a 'pool' designed into the cylinder head to hold oil for startup purposes. (Older Honda XR's were made that way, for instance.) The XS engine is not one of those, all the oil runs back to the crankcase through the cam chain opening. Then there's that whole 'wet clutch' thing too.

Honda XL250 head, you can see the 'pocket' under the camshaft lobes.

Castrol 20W50 and a few others still have ZDDP along with some diesel oils like Shell Rotella. A lot of the collector car guys will run Rotella for this reason.

 

[PHeller]

Can you get Rotella 10w40 or something thinner than the 15w40 that Wallie World carries? $10 a gallon is awesome, but I need something thinner during the winter.

 

[TeeCat]

I think Amsoil actually has something called Z-Rod for classic cars, to deal with that issue. I'll have to try to find that article again.

TC

 

[weekendrider]

TeeCat ,
I hunkered down in the corral, took a stick to draw on the dirt with and fingered this out for you.
It boils down to the "cling" after the fling. Or will the synthetic hold a film of oil while the balls make the full rotation in the races.
Or has it run off so quick there is very little so the balls are running dry on the top of their rotation.

All newer machinery runs on tighter tolerances now.
Thicker oil doesn't coat the friction points well so you end up running a dry surface.
A good way to ruin current motors is to run oil that has to high of viscosity.
An example would be the little brides newer Subaru. It uses 0-20 syn ONLY if you want a lifespan from it.

On the flip side older motors need the cushioning of thicker(higher viscosity) oil.
They will leave a film of oil the parts "ride" on.

I'm sure the newer oils are better than synthetics of 20 years ago.
But the technology of the XS motor is the same.

I'll be the first to admit I may be talking BS.
Another good example of real vs synthetic.
Chicken pan fried in grease or crisco. Which leaves the most grease in the serving plate?
Cling factor you need it.

 

[retiredgentleman]

I have used diesel oil 15W40 and it works fine, but the tappets are a little noisey. I now use 20W50 Pennzoil Motorcycle oil, it has 1100 to 1200 ppm ZDDP, clutch works well and keeps the tappets quiet. I believe the diesel oil has about the same ZDDP.

I have read that Castrol Syntec 20W50 is full synthetic (or is it semi-synthetic?) and has 1200 ppm of ZDDP. Its supposed to be labeled "Recommended for classic cars."

Here is an post from a few years ago. However, I find if I read too many of these articles, it just gets more confusing :



Be aware that diesel-rated oil, like Shell Rotella and Chevron Delo, used to be good for older motorcycle engines, but that is not the case any more, as of just a few months ago. This issue probably applies to Castrol GTX as well (which is good oil -- or used to be). I used to run Delo 15-40 in my cars and bikes, but now it looks like I will need to adjust this.

The problem is the EPA has mandated a big reduction in the use of ZDDP because apparently it tends to foul catalytic converters. This shouldn't be a problem with motorcycle specific oil, which is what I use now, specifically Castrol when I can find it. The workaround to using the good old oils like Rotella T and Delo nowadays is to use a ZDDP additive, which will provide your valve train, rings, and bearings with the sort of protection they need.

SF and earlier rated oils have higher ZDDP levels, but are almost impossible to find now.

There was a rather long thread about this back in November on the Yam650 list. Bill Denton, who is the list admin and a chemist to boot, has his own recipe. Here's what he has to say:

===============

FWIW, I've (officially?) made a change to my motor oil homebrew mixture to make up for what has been lost in the transition from SJ to SM (gasoline
engine oils) and CI to CJ (diesel engine oils).

My Old Blend:
1) 3 parts Shell Rotella-T 15W40 conventional
2) 1 part Mobil 1 Tri-Synthetic 15W50 synthetic

My New Blend:
1) 3 parts Shell Rotella-T 15W40 conventional (or 71% by volume)
2) 1 part Mobil 1 Tri-Synthetic 15W50 synthetic (or 23% by volume)
3) STP Oil Treatment @ 2 oz/quart of total oil capacity (or 6% by volume)

For a 2500cc oil change in the XS, use:

~ 1 qt, 28 oz Rotella-T
~ 19 oz Mobil-1
~ 5 oz of STP Oil Treatment

...or you could make it easy on yourself and just round up the Rotella-T to
2 qts, round the Mobil 1 down to 15 oz and stick with 5 oz of STP. The
additive will boost the total ZDDP levels to reduce wear in flat tappet
engines like our XS650's. ZDDP contains zinc, phosphorus and sulfur, all of which were reduced in SM and CJ oils to reduce catalyst and particulate trap fouling.

=============

Bill is using the STP oil treatment in the blue bottle. The stuff in the red bottle is supposed to be better, but seems to be NLA.

See also this:

www.zddplus.com/

Bill thinks what they have to say is legit, and he's done a lot of research on this subject.

This place has better prices than most on zddplus:

secure.mysuperpageshos...index1.htm

Here also is a letter from Castrol sent to a member of the INOA Nortons list, to which I also subscribe:

=============

Thank you for contacting Castrol North America.

Castrol is aware of articles in enthusiast magazines and web-sites, as
well as after-market parts manufacturer discussions concerning GF-4
engine oils and cam-shaft durability issues in older performance
vehicles. Some consumers suspect the lower level of ZDDP in GF-4 oils
may be causing these failures. Castrol is currently investigating this
issue.

If you wish not to use a GF-4 oil in your 1970 Cutlass, Castrol does
offer the following products that contain Zinc at a level that is higher
than the Zinc level found in oils (API SG) marketed during the "muscle
car" era of time:

* Castrol GTX 20W-50 (SL,SM)
* Castrol GTX Diesel 15W-40 (CI4,CH4,CG4,CF4,CF,SL)
* Castrol GTX High Mileage 20W-50 (SL,SM)
* Castrol HD 30 (SL,SM)
* Castrol HD 40 (SL,SM)
* Castrol Syntec Blend Truck 15W-40 (CI4,CH4,CG4,CF4,CF,SL) (Semi-synthetic)
* Castrol Tection Extra 15W-40 (CI4Plus, CI4,CH4,CG4,CF4,SL)
* Castrol Hypuron S 15W-40 (CI4Plus,CH4,CG4,SL)(Semi-synthetic)

Thank you again for your continuing patronage.

Castrol Consumer Relations

===============

I was confused by this letter, since it seems to contradict the EPA mandates. But I was informed by another list member that oils with viscosities of 50w at the upper end are not considered "conventional" anymore. So perhaps Castrol's above products will still be fine. If in doubt, though, add some zddp treatment.


Best,

Michael

_________________
Triple Tuning Forks Rule!

'81SH, '80SG, '78E, '77D

 

[TeeCat]

weekendrider... hello!

Your post is essentially the nugget of the argument I'd read somewhere previously about possible issues with ball bearings and synth oil. Though it makes perfect sense to me in theory, there is an article I read somewhere recently that counters the notion that synths will cause the balls to "skid" instead of roll, run dry, or develop flat spots. I'll have to track it down.

I do recall that one of the things the article pointed out is that, though the synths are more uniform than petroleum oil molecularly, they are not necessarily "slipperier". So this suggests to me that viscosity ratings for synth and petroleum may be comparable, but I suppose it's the resistance to heat and breakdown that's an important quality in synths.

Again, though, the only reason I went with 10W-40 this time is for winter (cold=molasses=too hard to kick=potentially torn sump strainer), and what they had was synth. This same oil is available in 20W50, though, and that would be my choice, were it not for winter cold.

RG...

That's some useful reading... thanks for this! This is actually the second time I have ever actually used a motorcycle-specific oil... this and the previous oil change. I'm trying to find the PDS for this oil and the Valvoline site did not seem to have it. I'll have to go home and look on the bottle to see if it contains ZDDP. There sure is a lot of data on this topic; the problem is trying to distill it all so you can make an informed decision at the cash register!

TC

 

[Max Midnight]

I do think that whilst in many ways the Internet is a wonderful thing, on the other hand it can raise more questions than answers.

Whichever forum that you frequent, the 'Which oil should I use?' question is of the most murky when trying to decide which way to go.

Now I'm just a simple lad who worked for motor manufacturers and was field based working with dealers after-sales areas.

I started when GTX was considered quite advanced and have seen semi and fully synthetic oils come onto the market whilst at the same time viscosity's have gone from 20W-50 to 0W-15.
Regardless of what oil was in the sump the only time lubrication failure was an issue was when there wasn't enough of it in the sump or it had been in there for many tens of thousands of miles.

Over the years I have come to the conclusion that provided you change the oil and filter relatively frequently it doesn't matter a hoot which make of manufacturing process of oil you use.

They all do the same job and (so far) I've not suffered lube failure or worn a motor out.

Bottom line is use whatever you are happy with.

 

[TeeCat]

Now I'm just a simple lad who worked for motor manufacturers and was field based working with dealers after-sales areas.

I started when GTX was considered quite advanced and have seen semi and fully synthetic oils come onto the market whilst at the same time viscosity's have gone from 20W-50 to 0W-15.
Regardless of what oil was in the sump the only time lubrication failure was an issue was when there wasn't enough of it in the sump or it had been in there for many tens of thousands of miles.

Over the years I have come to the conclusion that provided you change the oil and filter relatively frequently it doesn't matter a hoot which make of manufacturing process of oil you use.

They all do the same job and (so far) I've not suffered lube failure or worn a motor out.

Bottom line is use whatever you are happy with.

Say, we're twin sons of different mothers! I'm a simple lad too... simple being the operative word in my case!

I think I should be in good shape then, given that I am often the butt of much criticism for changing the oil in my TX about every 18 minutes. Well... not literally. But often!

(Also, perhaps not surprisingly, my oil temp has not climbed above about 100C (212-215F) since this oil change, though cooler ambient temps may be related to that.)

TC

 

[XSLeo]

TeeCat, your statement that synth oils are not slipperier is correct.
Dino oils at a molecular level look like you went out to a creek or river and shovel up the gravel. The gravel is composed of many sizes and shapes of stone. Now take that gravel and screen it out to separate the gravel by size and shape.
This is basically how dino base stocks get to be called synth oils.
Some synth oils are created from scratch and all the molecules are made the same size and shape.
Dino oils are like the shovel full of gravel, the synth is more like a shovel full of ball bearings.
Now imagine how much easier your engine will run with ball bearings or gravel.
This extra refining is why synth oil is more expensive.
In my experience with my Harley the synth oil lets the engine run cooler, about 20 degrees, get better gas milage, about 2 maybe 3, and the engine runs smoother.
Our XS's will get the same benefits.
The synth oils being bad for roller bearing engine as the XS or Harleys has been pretty much debunked. Many engine builders have never found a bearing that failed be due to the bearing "skidding" because of synth oil. Improper installation is the main cause of bearing failure.
When the XS650 first came out 30w oil was the right oil, mostly because that's all that was available. After a few years multiu-viscosity oils became available, Yamaha changed from 30w to 20w40.
Yamaha was about the only place to get the 20w40, still is. The diesel oils come close with the 15w40.
Most modern bikes call for the 10w40 or a 20w50. The 10w40 is mostly for the water cooled 4 cyliners. Air cooled the 20-w50.
Valvolene makes a 20w50 motorcycle oil. As I recall the ZDDP is about average in this oil. They also make a Racing 20w50 for car engingines with a very high ZDDP content.
I use a quart of the Racing 20w50 then enough of the bike 20w50 to fill it up. This is a warm weather blend.
For colder weather the quart of racing oil with a top up of of the 10w40 should work for cold weather.
I don't think an oil lighter than the 10w40 bike oil should be used, most are made for cars and have friction modifiers to let cars get better milage. These modifiers are what hurt the clutch. Any oil with the starburst emblem that says energy conserving should be avoided.
They do make thinner oils for snowmobiles but I don't know much about them.
Leo