Choosing the correct Oil for a wet-clutch Motorcycle

It does not "magically" become a higher viscosity oil.

All oils (used in combustion engines, I don't want this to get esoteric) thin as they warm. A 5 weight oil at 20* may be more viscous than a 50 weight oil at 150*.

Historically, oils were sold in a single viscosity grade. A common one that still exists is SAE 30W oil. A single oil will thin as it heats in a more or less linear fashion.

Multi weight oils thin less as they heat, due to either the addition of Viscosity Index Improvers, or due to the properties of the base (synthetic oils). Compared to single grade oils, as multi grade oils heat up, they don't think as quickly as single grade oils. Thus in the case of 5W-30, a 5 weight oil when at the tested temp (which I believe is somewhere in the operating range) will be expected to have a similar viscosity (thickness) as a single grade 30 weight oil. As the multi grade oil heated, it didn't thin out as fast.

So.. great, we should all run 0-150 W oils for the best of all worlds!

No.

Two problems:

1. Viscosity Index Improvers aren't great. For one, they aren't great lubricators, but the bigger problem is that they break down much faster than the rest of the oil. They are made up of long chains of polymers that shear apart, after which they don't work to slow down thinning. They also tend to break down into sludge. This means that a 5W 50 oil may work exactly like that fresh out of an oil change, but after life in an air-cooled engine getting munched through transmission gears, it can turn into a sludgy thin 5W oil before that next oil change. Using oils with a larger range 10W-40 vs 10-W30 generally means a shorter oil change interval is warranted because more VII's were used to keep the oil thicker once heated. Synthetics tend to start with more favorable properties (they thin less when heated before the addition of VII's), which is one big reason they can withstand longer oil change intervals.

2. It is pretty easy to have too thin an oil. Metal expands when it warms, so a cold engine has more clearance- a few thousands extra all across the board. When cold, a too thick oil will be slow to get pushed through the lubrication system, leading to wear from insufficient oil on startup. But a too thin oil may not be able to coat and provide a sufficient film for engine parts to glide on instead of pushing through to metal bearings. Engines are designed with a specific oil spec, and generally engines with looser clearances spec thicker oils. One reason some auto engines now spec 0 weight oils is because better manufacturing has allowed them to tighten bearing clearances (and lighter oils help fuel economy). A small block Chevy from the 60's doesn't have bearings that tight, and needs some syrup to the oil to avoid wear.

Important to note that the first number in a multi grade oil is NOT just the startup thickness- That is the base viscosity of the oil. The oil never gets thicker than that- it just doesn't thin as much as one would expect if it was a single grade oil. If an engine was built expecting a 20W oil, and a 5 weight oil is put in instead, the engine may see adverse effects in the performance window where the 5W oil is thinner.

Also notable that all oils of a given grade still don't act the same. I've observed in cold temps that many synthetics will pour easier than non-synthetics. That same difference I observe when pouring the engine will observe when starting, for better or worse. I fully expect that at whatever temp the "W" portion of the viscosity is measured both synthetic and non-synthetic will be within spec, but that doesn't make them the same through the temp range. Multi-grade oils measure viscosity at two temps- oils can meet that spec while performing differently at other temps.

http://www.machinerylubrication.com/Read/1327/viscosity-index-improvers

 

The 'magically' was tongue in cheek, lol, thats why I put it in parenthesis, or whatever those commas are !!

I know it doesn't magically do anything, BUT, 5W-40.....until 0W-50 becomes available will STILL give your, or my engine THE broadest range of protection available....perhaps unless you actually DO live in Saudi Arabia, Sub Saharan Africa!!

and yes, you still need something that has better than average 'shear' strength, regardless of it's viscosity range, especially in our nightmare gearbox oil chewing factories, as motorbike gearboxes tend to be!!

 

Quotation marks?

 

Thought they had to be 'double'??

 

If you use single quotations marks, then you should use double quotation marks for a quote within a quote. If you use double quotation marks, then you should use single quotation marks for a quote within a quote. For example: "When I say 'immediately,' I mean some time before August," said the manager.

MattiThundrrr: putting the "punk" in punctuation!

 

No 5w 40 does not give your engine "the broadest protection possible" for the reasons mentioned above. Putting a 0 or 5W oil into an engine speced for 20W is not a good idea. A 0w oil is much thinner than a 20W base oil, and that matters. It also matters how they get a 0W oil to act like a 40 viscosity oil at temp.

 

Um....no. Recall that oils have changed along with engine materials and enginering practices. Tolerances between parts are tighter now. Our engines do not have surface treatments on the cylinder walls, or on the pistons, or modern alloys. Running lower than the recommended viscocity will increase engine wear, and eventually cause you (or the next owner) to have a very bad day.

It's also worth noting that the lower viscocity oils are meant to provide improved oil flow during cold weather. Unless you're out riding in sub 20ºF temperatures, that 5 weight base oil is providing no benefit whatsoever.

 

"It's also worth noting that the lower viscocity oils are meant to provide improved oil flow during cold weather. Unless you're out riding in sub 20ºF temperatures, that 5 weight base oil is providing no benefit whatsoever."

We'll have to agree to disagree, on that one

I'm still getting the BEST 'flow'/protrction for my cold starts....regardless of the actual outside temperature....remember, once she starts to warm, my 5W.....'magically' lol, becomes 40W...But, I DO understand what you are saying, and certainly, back in the 70's/80's i could only really find 20W-50!

 

Empirical evidence and I are close friends. Believe the marketing department if you want, but your engine isn't going to like what they say.

 

I understand what you are saying, and I DO appreciate your input, and advice......

5W..not THAT much 'thinner'...incorrect term, I know, than 10W, which was readily available, late 80's......and some of my previous XJ's ran it.....and other grades, quite successfully for over 140K miles, so I'm sticking to my guns on 'cold start protection' is just about THE most important job, one can ask of an oil!

I will ask this though.....why do the American spec (Canadian?) XJ's not come with an oil cooler as standard?

Most of the Euro, certainly British models do......and I can empirically and categorically state, the States is generally a LOT warmer, than the UK ....I'd have thought an oil cooler was a MUST have, over here?

 

They didn't specify 20w 50 vs. thinner weights because "better" oil was not available, they did it because it is an air-cooled engine subjected to high temps and needs thicker oil.

The CB750 nighthawk was one of the last UJM's made, well into the 1990s with air cooling. It specs the same 20w 50 for Summer use.

 

My opinion is that the U.S. market did not get oil coolers for a few reasons. Firstly, Yamaha U.S.A. was known for trying to eek-out every bit of profit they could, so U.S. machines often got different equipment (e.g. the crappy first-generation Virago starter that nobody else had to deal with). The other reason is the 55 mph national speed limit of the time. The XJ engine is well cooled without an oil cooler when riding under those conditions, so Yamaha U.S.A probably didn't think it was necessary to fit an oil cooler.

 

And yamaha was in no way being naive in assuming that no American would exceed the posted limit!

 

Matti - glad you are still poking your head in here once in awhile.

I often times misuse 'the single' as a way of "quoting" someone but not necessarily verbatim.

 

THAT'S WHAT SHE SAID!

 

Will the Rotella T4 15w40 work for me in the Texas heat or will I have to go with the 20w50 for more heat?

 

i use the cheapest walmat oil i can buy. i've got 55,000 miles on a superglide doing that. the trans is fine. chaincase too....

 

You'll be fine. I'm only two hours north of the panhandle.

 

Juat be sure that it's JASO MA rated if you put it in your XJ. The starter clutch will thank you.

 

Good morning, all.

New to the forum and have been marinating in all these oil posts

Thank you for all the knowkedge and experience you share on this forum!

For the original guys, long time contributors and riders - what do you use and find works best for your final drive oil?

Thanks a bunch!

BTW my ride: 1982 XJ650 MAXIM

 

NZ models came with them and temps here average 68 - 77˚F in Summer

Yeah we got the different wheels with twin discs as well, at the time our National limit was 50mph

 

You paid attention to that?!!!

 

That sounds wonderfully pleasant, and cool.

 

Don't be silly, we took it as more of a minimum, rarely below 60-70 mph, even 20mph over the limit the fine was only $50

Even the winter average is 53 - 61˚F

 

Ick. That's way too hot for winter.

 

As long as there's minimal humidity in the summer time, I'd take that weather hands down

 

^ yea, after so many decades living in a cold climate, the novelty of below freezing temperatures starts to wear off.

Although haveing defined season changes is a requirement to appreciating nature.
One of my brothers moved to L.A. - he had a difficult time adjusting to a climate that pretty much stays the same 365 days a year.

 

In Canada, we have 2 seasons; winter, and construction.

 

^^^Same as Wisconsin

 

I think fun-time is over. Let's keep this thread on track.

 

I've been very happy with the operation of my bike using Castrol 20W-50 4T oil. It goes for $6.99 a quart at Autozone. My kevlar clutch with slightly heavier springs is fairly new. The difference between the old and new set up makes for much more enjoyable rides with its smooth operation.

 

https://www.castrol.com/en_us/unite...ke-engine-oil/4t-4-stroke-motorcycle-oil.html

 

Old thread, I know. But...

1. Are all the parts necessary to rebuild clutches available here from Chacal?
2. What kind of cost are we talking about for all the necessary parts?

Thanks.

 

Most definitely. Have to contact him for a quote

 

This place is the best! Thanks.

 

read this
CLUTCHES 101-Part 1: the 400/550/600s with pics

 

Great stuff!! Thanks.

 

So are you saying that Rotella T-6 5w-40 full synthetic is a big no-no for our XJ750 bikes? And that Rotella T-4 Triple 15w-40, which is cheaper, is actually better?

And somewhat related...is it possible that using T-6 5w-40 could cause a slight oil leak?

 

P

Price has no bearing on the suitability of an oil to the intended application. Specs are specs and standards are standards.
Rotella has been a go-to oil for motorcycles for over 30 years, in large part because of the ZDDP content.
Any oil that meets JASO specs is perfectly fine to use, whether synthetic or not.
I use the Rotella T-4 because it's commonly available, meets the required specification, and is cost effective for me.

 

That's fine. My questions were simple: Is T-6's full synthetic/5w-40 composition bad for the old XJ750's, or not, and could it possibly contribute to a slight oil leak if full synthetic oil was never used in the bike previously? If so, I'll swap it out immediately for T-4 Triple Protection. My reason for choosing T-6 is that my buddy swears by it for his older Honda Magna V4s. But those bikes are water cooled, not air cooled. It never dawned on me that T-6 could be bad for XJ750s.

 

1. See my previous reply. If it's JASO MA (or better) compliant, then you can use it in any motorcycle of any age.
2. No. Synthetic oils do not cause oil leaks.

 

OK. It's just that in reading through this entire thread I haven't seen one person mention Rotella T-6 5w-40, even though the discussion of grades other than 10w-40 came up, and even though just about everyone mentioning Rotella talked about T-4, not T-6. And I've read elsewhere that full synthetics are not always recommended when it comes to older engines. But if the T-6 can't do any harm, or cause any leaks, then at least I know it's safe, although I'll probably get and use T-4 in the future since it does a fine job and is cheaper.

 

T-6 is quite new in comparison to the thread (as is T-4). When I first posted this info (prior to making this thread) Rotella had no sub-types; it was just Shell Rotella for airplanes, or Shell Rotella for diesels, and it came in a variety of weights.
I don't update or list which oils to use, because they change all the time; either by name or by formulation.
In the first post there is a link to the JASO website, which has a fairly comprehensive list (not sure if it gets updated often or not).
Otherwise, read the bottle and look for the certification and compliance marks. Everything else on the label is just shiny-shiny to get us to buy one brand instead of another.

 

Well...The T-6 is JASO DH-2 and JASO MA certified.

There was some discussion regarding the difference in weight -- 5w-40 vs 10w-40, and whether the 5w-40 was too "thin", vs 10w-40, but nothing conclusive was ever really discussed. Maybe it's a matter of personal preference and/or where you live. All I know is anecdotal evidence in that my buddy who has been refurbishing 3rd gen Honda Magnas swears by the T-6 and that's all he uses.

 

you can use syn oil. we have had a few here who used it then changed back because of starter clutch issues.
then there are others who used it with no issues.
I run T4 because it is within the spec range of oils for the old xj. i have no need for a 5W as I stop riding at 32 degrees F

 

Thanks. That was the kind of response I was looking for.

 

WOW. The synthestic oils that don't cause any troubles are the ones that are JASO certified or JASO compliant.
I guess I just suck at answering questions clearly anymore.

 

I think you answered clearly. I was just letting him know that there were a few who changed back from synthestic oil due to problems with starter clutch. I think that those who had problems were near the end of the starter clutch life to begin with.
oil is like gasoline some swear by a brand or type and thats what they use.
I just changed fuel brands and my podded bike feels like it is running better but that may just be the weather improvement warmer mornings.
with oil I am still going to change it based on Yamaha spec for miles, would rather save the few dollars for other things.

 

Apologies for the overreaction. The last six months of work have been unbearably aggravating.

 

Fwiw, I was using a synth 5w-40 in my GS a couple of years ago and it was quite good. The specced oil is 10W40, but there was always a bit of cold clutch drag, which is why I gave the 5W-40 a whirl; it worked really well to banish the cold clutch drag, an an unexpected (but not totally unsurprising) benefit was the sudden availability of a couple of extra horses at the wheel, which only goes to show how much internal engine drag plays a part in things.
I had planned to use the 5W-40 in winter and revert to a 10W40 in summer, but after the first winter using the thin synth, the base gasket started leaking like a good'un, so since then I've stuck to heavier grades. The engine is currently in bits for a top-end refresh and new base gasket. Once I've buttoned the engine back together, and run the new rings in, I'll be shifting back to the 5W-40 for long-term use. There was no clutch slip to speak of, even though this is a car oil.

On the XJ9, I've been using 10W-40, 15W-40 with no real downside, but there's a bit of clutch stickiness there every cold start. The caution against using synth in this engine because of the starter clutch is what's dissuaded me from doing so.