Topic: 20w50 vs 10w40

[Kevin D]

If i'm reading this right, for my K1, Soichiro is recommending 20w50 for use above 32F

[jaknight]

KEVIN D,

   I believe that like many other things, its open to interpretation.

   I live in Arizona and the summers here are incredible!!  I use 10W-40W, with frequent changes ( a lot sooner than what Honda recommends because of incredible dust and heat).  All the guys I talk to in this state use 10W-40W.  But......... I did meet one old timer, a member of the Old Geezer's Club ( as if I should talk ), who had a beautiful Gold Wing that looked and acted very minty.  He swore by the 20W-50W because of the Arizona heat.  He also believed in very frequent oil changes because of Arizona conditions.  500 to 700 miles is when he changes oil, as I do, except of course for a long trip where you are putting on 1200 miles or so.  If the trip is longer, you make provisions for changing the oil.  It does keep things clean and tight, and I am willing to spend the time and money for that.

   We have had days here when the temperatures get to 124 degrees and have had times when the temps stayed above 114 for a week and half or so.  Then, 20W-50W seems logical.

   But, back to your real question - - - - - it looks as if what I can see of the text on that page says 10W-40W and 20W-50W are normal oil weights for normal conditions, as the text puts it.

   ~ ~ ~ jaknight ~ ~ ~

[Harry]

Looks like a printing mistake to me - should be the other way round?

[MRieck]

Looks like a printing mistake to me - should be the other way round?

I agree...a printing error.

[cb650]

This is like askin whats the best color for a bike.  I use 20/50 only unless I'm going on a long hot trip then us straight 40.  I dont beleive a mult will hold up as good.  10/40 is good for cables.




                      Terry

[jdpas29]

unless you are in a super cold environment, 20/50 is preferable.  with an old bike, shear is the enemy.  20/50 will not thin out over a few thousand miles as 10/40 will.

the only drawback is that at moderately cold temps (20 degrees to 50 degrees) it takes a little longer for the bike to warm up properly... big deal!      if you plan on running your bike in temperatures less than 30 degrees very often, stick with 10/40.

[TwoTired]

the only drawback is that at moderately cold temps (20 degrees to 50 degrees) it takes a little longer for the bike to warm up properly... big deal! 

No offense. but...
Actually, I think it is a big deal.  It's more than the longer warm up time that effects YOU.  The slower oil movement when cold, starves the engine of some lubrication during that warm up period. 

If you are starting your bike at temps below 32 degrees, you should be using 10-40W oil.  At normal engine operating temps, it probably doesn't matter if it is 10-40W or 20-50 weight.  At high operating temps, then you want the 20-50W.  But, only if you aren't starting the engine when temps are below 32 F.

As for oil thinning out with high mileage, I agree it does.  But, Honda's recommended oil change interval is 1500 miles.  And, I think 1000 is better for engine longevity.

I just don't agree that using a high viscosity oil to extend the oil change interval is best for engine life.  Oil wears out.  If it is worn out, then replace it!

Cheers,

[GeoffT]

I Think I'll stick to 10-40w. I know I run a risk with our really high temperatures. Two summers ago we had 25 degrees for two days - man it was hot.  

[cb(r)]

first of all I also believe the book is wrong.

secondly,  even though you have an older bike there has been advancements in oils.

check with synthetic for MOTORCYCLES.  this to me is the best oil to use. the oil tends not to break down as easy when your transmission gears are moving. gastrol used to have a good explanation on their web site.  not sure if they still do.  they will also give you the temp ranges for the particular oil weights you are looking for.  I live in the midwest and have rode with roads clear and 2 foot of snow on the ground but I mostly ride in the summer month highs of the low 90's f.
I generally will  not use 20w 50 unless the bike or other machines are well used and I am riding during hot summers.

[eldar]

Thicker oil flows slower, bottom line. So even in warm weather, it will take slightly longer for 20-50 to flow and protect than 10-40. Startup is where most engine damage occurs. Granted, in warm weather, this is lessened but I would rather use a good oil cooler and 10-40 than 20-50.
Also new oils ARE better than 30 years ago. What then was mobil 1 30 years ago is now your no name brand sold at cheap out parts stores.  So oil change intervals do not need to be so close unless you ride hard and constantly hold high rpm.
I do however change my filter everytime I change oil. I do not believe in chaning the oil and not the filter.

[ProTeal55]

I am a big fan of 20W50.
Used it in my cars in the past , with nothing but good results.
It's in the 55 , and in the CB at the momment...
If my truck wasn't a diesel , it would be in their as well...
But, Is a truck really a truck if it has a gas motor ?

And, I agree with Eldar. Changing your oil is pointless if you keep the
old filter in the bike . Might as well change them both at the same time....

[ofreen]

And, I agree with Eldar. Changing your oil is pointless if you keep the
old filter in the bike . Might as well change them both at the same time....

How many miles do you go between oil changes?

Greg
'75 CB750F

[Jim Shea]

Greg,
How long is a piece of string? 
I was advised to change oil every 1000 miles and change the filter every other oil change. I think I will change both at the same time, might as well as the filters are cheap!
Jim.

[ofreen]

Greg,
How long is a piece of string? 
I was advised to change oil every 1000 miles and change the filter every other oil change. I think I will change both at the same time, might as well as the filters are cheap!
Jim.

I won't presume to tell people how often they should change their oil and filters.  If they want to do it every 1000 miles (or 100), it is OK with me.

However, it is my experience that 1000 or 1500 mile oil changes are unnecessary under normal conditions.  I change the oil every 3000-4000 miles in my bikes.  I change the filter every other oil change.  The last few years I have been using BMW dino oil because that's what is sold at my favorite motorsickle shop.  All my bikes have a lot of miles on them, with the 750 approaching 100,000 miles.  I live in southern Idaho, so the 750 is ridden in both hot and cold temperatures (16F yesterday morning.)  The 750 uses about a cup of oil in 3000 miles, if that.  I believe that if the oil change regime I use was harmful, it would be obvious by now.  Someday, I'll tear the 750 engine down and see what's in there.  But based on the way it is running, I think that time is still a ways in the future.

Again, I'm not telling people what they should do, just offering information based on actual experience for their consideration.

Greg
'75 CB750F

[Jim Shea]

BMW dino oil?? what is that used in normally? BMW cars or bikes? also, what weight is it?
I feel guilty having used a cheap oil last time and I want a 'better' oil?

[ofreen]

BMW dino oil?? what is that used in normally? BMW cars or bikes? also, what weight is it?
I feel guilty having used a cheap oil last time and I want a 'better' oil?

It's the motorcycle oil.  I think it is made by Spectro.  It's not the synthetic stuff BMW sells.  I usually use 20-50w unless I know most of the miles will be in the winter, then I'll use 10-40w.  The oil in there now has almost 3000 miles on it.  It will be time to change it about the time the weather starts to warm up.

Greg
'75 CB750F

[ProTeal55]

I haven't had my CB a year yet , but as a rule I change the oil in my other cars/bikes
each spring , after they are "awoke" from their winter nap. Fresh oil & filter, along with new plugs
makes a good start to the season....

The racecar got it's oil changed every 10 passes , but that was a 16:1 compression
motor , and it liked it's oil 

[cb(r)]

just a couple of things to add.

I use synthetic and have had great luck with it.  To address the slow movement at startup I have to say this is true. According to everything I have read on sythetics though the oil molecules "sticks or stays" to parts.  I think this "sticks" is a technical term?  anyway you will have oil left on moving parts after they have stopped.  so slow movement at initial start up is not that big of a concern for me unless the bike has been sitting let say over the winter, three or more month.  Then again, everything is a concern to me at initial startup in the spring. It is especiallly true on an older bike that I have spent countless hours rebuilding or babying. 

as far as oil changes go when using a synthetic?  well I just watch for discoloration and I actually smell it.  ya funny but true. just something my brother use to due years ago to see if he scorched anything.   I usually checkthe oil at 500 mile intervals.  The big thing to remember to do when it comes to having clean oil ,other than changing your oil filter during changes, is to keep your air filter and cleaner clean.  Unless you have a bad seal  o-ring or gasket how else do contaminants get into your bike, car, boat, etc??

one other update on oils.  friends of mine that drag race cars are starting to use a brand of oil called Royal Purple.  these guys swear by it.  they also have about $10,000 to $20,000 dollars just in engine work.  I believe that this oil might be something to investigate.  I also believe they have it for motorcycles.  has anyone used this brand on their bikes?

[Bob Wessner]

Re: Royal Purple.. it must be good, $10/qt. 

http://www.rpmoil.com/shop/quick_order.html

[dusterdude]

royal purple is good stuff

[cb(r)]

Re: Royal Purple.. it must be good, $10/qt. 

http://www.rpmoil.com/shop/quick_order.html

I heard it was expensive but holy moly!

[eldar]

Amsoil is pricy too. But is very good. That oil is rated for an average of 50,000 miles before a change is needed. You just change your filter normally. They also make motorcycle oil which is also long life. So if you do keep your air filter clean and all seals good, this oil would work very well.

I use a 10-40 oil though. I use havoline which is auto oil but it does not have the energy conserving additives. I have never had clutch slip and aside from an occasional hard shift or me not shifting all the way I have never had clutch or tranny issues.

I would like to get an oil cooler since cooler oil is always better in hot weather. I change about every 1500 - 2000 miles but change the filter every time. Filter is only about $3.

[ProTeal55]

Royal Purple is not worth the money , but that's just
my opinion...

[bryanj]

OK here we go again. Honda spec 10w40 as the oil restrictor jets are tiny and the 20w50 takes too long to thin out starving the cam--its ok when its already hot so in Arizona you will get away with it. The 1500 mile change specified is because the oil lubes both engine and transmission and its the transmission that "chops" up all those oil molecules and wrecks its lube properties. Now i know you US types go for long rides but over here in UK we tend to mostly do short journeys which also means you get more condensation inside the engine and therefore water in the oil--another reason to change it more often. Finally DSS sells oil filters at 5 for £10 ($18?) so comparing that to the price of oil it makes sense to change it EVERY time as i agree in what is the point of pumping clean oil through a dirty filter

[8 Track]

Unless you have a bad seal  o-ring or gasket how else do contaminants get into your bike, car, boat, etc??

Contaminates come from the combustion process and the acids produced from same process.  Gas engines are filthy machines compared to diesels, on the inside, that is.  And when you store your bike with last year's oil in it, you've left those acids in there to work their magic alllll winter.  Now- is this really true?  I don't know, but it's what I've been taught and it's what I practice.  Besides, next spring, all I have to do is push the button and ride, not change oil first!  BTW, I've run 10w40, 20w50 and 30w and the only difference I can tell is she likes castrol more.