Author Topic: Oil viscosity choices? (Read 14560 times)

cakey · « **on:** December 07, 2013, 11:49:23 PM »

Has anyone had any experience with trying different oils in the CB750's. It's time to do another oil change on my GL1000 engine and have been thinking about changing to 15W40 because it very rarely gets below 30 degrees and 95% humidity here in the tropics all year round so was thinking about running a bit thicker oil. Basically here in Darwin it's just down right nasty hot all year round. I will also need an oil for myCB750 rebuild and the 10W40 is very pricey here.

I went looking at the auto store and the choices I have are:

10W40 $85 4lt
15W40 can't get it
15W50 $35 4lt

Any thoughts?

ken65 · « **Reply #1 on:** December 08, 2013, 02:04:49 AM »

gday cakey, im in brisbane and use castrol 4t 15-50, does the trick, cheap and easy to get, ken

tomkimberly · « **Reply #2 on:** December 08, 2013, 02:15:17 AM »

Yea, another oil thread. Make sure it's wet......

AJK · « **Reply #3 on:** December 08, 2013, 02:18:30 AM »

Hi Cakey,

I'm in Sydney, & I know how hot it can get up in Darwin. Stick with 20w50 in the hot, otherwise its going to thin out too much. Hondaman basically says to use 15W50 as a minimum as the top end chews up the oil in our machines. He says its better to use 20W50. Given 30 degC as a minimum in Darwin (86 F), i'd definitly stick with something thick.

Not sure what your availabilty for Motul or motorcycle specific oils are available to you. I'm considering going the Penrite HPR 15W50. Its suitable for diesel & motorcycles but Penrite is known for having high zinc levels and our own racing drivers at Bathurst use it. I.e.
http://www.penriteoil.com.au/engineoils-products.php?id_categ=1&id_products=8

I'm using Motul 3000 at the moment as i'm still running in new rings, but will go over to either Motul 5100 or the Penrite as mentioned on my next change.

Enjoy the following links. Again, varied in topic but interesting anyhow.

http://forums.sohc4.net/index.php?topic=46897.0
http://forums.sohc4.net/index.php?topic=96374.0
http://forums.sohc4.net/index.php?topic=8237.0
http://forums.sohc4.net/index.php?topic=123721.0
http://www.machinerylubrication.com/Read/518/motor-oils
http://forums.sohc4.net/index.php?topic=119643.0
http://forums.sohc4.net/index.php?topic=103432.0

PS: Be sure to state celcius so our friends in the USA know the units we are talking about.

PS2: Apologies. I just realise you mentioned GL1000. Thats ok. The above still applies.

cheers
Alex

cakey · « **Reply #4 on:** December 08, 2013, 02:30:36 AM »

Thanks Ken and AJK. Great info. I know I can definitely get the 20W50 in a specific motorcycle oil from Repco but can you tell me if the other oils you mentioned are specific motorcycle oils or general auto? I have not seen them up here?

Penrite HPR 15w50
Motul 5100
Castrol 4T 15W50

Thanks for getting me on the right track.

AJK · « **Reply #5 on:** December 08, 2013, 02:45:14 AM »

All those you mentioned can be used. The Castol and Motul 5100 are motorcycle specific, the Penrite can be used (see the writeup on that link).

Actually, Penrite has released motorcycle specific oils as well. I forgot this link earlier on.
http://www.penriteoil.com.au/products-categ.php?id_categ=7&id_subcateg=95

If you stick with a Motorcycle specific oil, then you can't go too far wrong, but i think 15w50 should be a minimum up there in your temps.

I have been using Motul 5100 for years in my blackbird and I love it.

PS: For the USA guys, as an aside, I believe Penrite is coming your way soon, so perhaps something worth checking out if the prices are right. They have been around for a while (1926), but I know you have plenty to pick from already

cakey · « **Reply #6 on:** December 08, 2013, 02:51:24 AM »

Thanks AJK. I am also running in my GL1000. rings after a rebuild and am ready for a 500km oil change but with that and the K1 just about finished it's starting to get expensive at $80 per 4lt.

I started researching and ran into this article below and started wondering if I had to use motorcycle specific. It throws it out there. I will read through your links. Thanks

http://www.ducatimeccanica.com/oil.html

AJK · « **Reply #7 on:** December 08, 2013, 02:56:24 AM »

I'd go another few thousand kms on mineral, then go to semi-synth, but thats me. I.e. Let the rings bed in properly on the first couple of oil changes.

Yep, the first link in my previous post mentions this
http://forums.sohc4.net/index.php?topic=46897.0

I think these days we could simply say, "Just put oil in it"

... And that would be good enough

cakey · « **Reply #8 on:** December 08, 2013, 03:01:11 AM »

Nice work. Thanks for the advice on the rings. Thumbs up!

cakey · « **Reply #9 on:** December 08, 2013, 03:06:45 AM »

Could win stupid question of the year award but would semi synthetic be classed as mineral based? Or would it need to be labelled mineral based to assist with the rings bedding in? Just that when I was out today i only saw semi synthetic and fully synthetic oils.

AJK · « **Reply #10 on:** December 08, 2013, 03:14:39 AM »

Its still mineral based from my understanding, with enhanced additives. Type 4 mineral?? Can't remember now.

I'd stick with something purely mineral for say another 2000kms, (not even a semi-synth). Something like Motul 3000, (not 5100 which is semi-synth). Important to swap out your filter on every change for you as you will have many metal particles in there with new rings.

Stay clear of fully synth until you have run it in properly and clocked up some kms. Not sure how the fully synth would affect your clutch. You might have to suck it and see. Personally i wouldn't bother with it on our machines, but thats just me.

Oil changes is your cheapest insurance if you want a long life motor (& minimum repair bills). So change it regularly, especially if you feel like gear changes are becoming more difficult due to oil becoming too used/old.

PeWe · « **Reply #11 on:** December 08, 2013, 04:56:10 AM »

I know better now thanks to all oil threads.
I'll go for 20W-50 which is recommended. Mineral, JASO oil.
xxW-40 can be used when it's colder and short driving.

Bankerdanny · « **Reply #12 on:** December 08, 2013, 11:59:09 AM »

With a liquid cooled engine like the GL I don't see any advantage to using something other than the recommended 10-40.

For an air cooled engine like the SOHC4 i do like to run 20-50 during the hot summer months, particularly since I live in a crowded city, which means traffic and many stop lights.

dave500 · « **Reply #13 on:** December 09, 2013, 01:16:06 AM »

rx super 15/40

cakey · « **Reply #14 on:** December 09, 2013, 02:30:23 AM »

Quote from: Bankerdanny on December 08, 2013, 11:59:09 AM

With a liquid cooled engine like the GL I don't see any advantage to using something other than the recommended 10-40.

For an air cooled engine like the SOHC4 i do like to run 20-50 during the hot summer months, particularly since I live in a crowded city, which means traffic and many stop lights.

I have really wanted to avoid using anything other than standard but where I live the average sea temp is 32 C or about 90 Fahrenheit think and tap water comes out at an average between 90-100F depending where you are. I went on the Toy Run for kids on the weekend and several other riders were saying they run thicker oils but they were not sure about my older bikes if it would effect it. Basically it's bloody hot here.

I picked up the Castrol 4T 15W50 today at a lot cheaper price and will use the mineral as suggested whilst breaking in the bikes. Then maybe move onto the semi synthetic Deisal oils later on. Had a walk through the car oils section today at the auto store and found another two deisal oils that are recommended for motorbikes. Heaps cheaper than the synthetic motorcycle oil I was buying.

Thanks everyone for the advice. I have learnt heaps on the subject.

Bankerdanny · « **Reply #15 on:** December 09, 2013, 08:35:30 AM »

Given the difference in cost (which I find rather confusing) I would go ahead and use the heavier weight oil in the GL, it won't hurt anything. But price being equal, I don't see an advantage because the liquid cooling of the GL should keep oil temps stable as opposed to an air cooled SOHC4, where I absolutely would run a higher weight oil, and in the case of a very hot location like yours, seriously consider synthetic.

Just make sure that the oil is formulated for motorcycles and made to work with wet clutches. Modern car oils have additional anti-friction additives that are not beneficial in a clutch where too little friction is a bad thing.

dave500 · « **Reply #16 on:** December 09, 2013, 11:33:17 AM »

dont use synthetic or semi synthetic diesel oils,the clutch will slip,most of these are for modern diesels which these days have particle filters and a sort of lean burn ecu controlled fuel system and mostly have the wrong slippery stuff in them.

millispartners08 · « **Reply #17 on:** December 09, 2013, 01:19:50 PM »

I use hpr gas LPG penrite mineral oil which I have heard I think dave 500 endorse before.
It is found at bursons auto parts here in Australia. I spoke to a penrite rep at the geelong speed trials revival recently and he said to stick with mineral for our bikes, most penrite mineral diesels are ok too he said, as long as it's jaso MA approved for suiting our wet clutches

CB750F2 · « **Reply #18 on:** December 09, 2013, 06:36:34 PM »

G'day Cakey.I live in Ayr which is about an hours drive south of Townsville. The maximum temperatures vary between 26 to 35 C. I use Penrite HPR30 20W-60. This is a Premium Mineral Oil with full Zinc additive. The Supercheap Auto Stores carry Penrite. Pat

cakey · « **Reply #19 on:** December 09, 2013, 07:01:21 PM »

Thanks for the heads up Pat. I will check it out. Rob

dave500 · « **Reply #20 on:** December 09, 2013, 11:37:47 PM »

i never use penrite,you must be thinking of cb750f2 ?
http://forums.sohc4.net/index.php?topic=99237.msg1107056#msg1107056

millispartners08 · « **Reply #21 on:** December 10, 2013, 02:21:33 PM »

Yep sorry dave 500.

timbo750 · « **Reply #22 on:** December 10, 2013, 03:09:15 PM »

I was under the impression that we had to use a motorbike oil as the normal engine oils can be an issue with the clutch. What is that I need to look for in a normal engine oil that affect the clutch?

Sent from my GT-I9100T using Tapatalk

TwoTired · « **Reply #23 on:** December 10, 2013, 03:18:57 PM »

Generally if it says "energy conserving", it will have friction modifier added, and clutches work on the principle of friction.

But, there is also the concern if there is enough zinc to keep the old engine happy.

You are pretty much safe if there is a JASO-MA printed on the bottle.

donpark1086 · « **Reply #24 on:** December 10, 2013, 05:32:05 PM »

Here are two viscosity questions to ponder. First consider that engine oils at the thin end of the range might be 0W20 and at the thick end 20W50.

First question. If your bulk oil temperature in the sump is 110 C, then maybe in bearings and the ring zone the oil might be 130 C or so. Let's call this the oil's temperature when it is "on duty" and working to lube things. Then what is the difference in viscosity between 0W20 and 20W50 at 130 C?

Second question. If viscosity is the oil's physical property that separates the bearing surfaces, then how does the oil film thickness change with changing viscosity. For example, does doubling the viscosity double the oil film thickness? Or is it some other relationship like squared or square root, or cubed or cube root?

When we answer these questions, we will answer this thread.

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Author Topic: Oil viscosity choices? (Read 14560 times)

ken65

AJK

AJK

AJK

AJK