motor oil: can you use anything with the right specs

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Hello again people,
I'll have to do an oil change on my new bike soon for the first time. The manual for my Kymco Pulsar only specifies SAE 15W40, API SF. There's a bewildering array of oils of that spec. I'm not sure if any oil with those specs will do, or does it have to be specifically for motorcycle or have other properties? Some of the 15W40s for example seem to match but are labelled as being for diesel engines.

Seb

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Pretty much. Newer oils (ie, higher spec) can cause clutch problems as SF is a pretty old and obsolete standard as far as car oils go. There are a few that are known to often cause problems, such as the Castrol Magnatec.

All the best

Keith
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czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Thanks for the real quick reply. Guess I'll have to buy motorcycle specific stuff and pay the expense. A bit annoying as my manual states it needs a change about every 2000km.

Seb

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Just get Morrisons/Tesco 10w40, your bike isnt going to moan at you... especially since it states every 2000km.

Its £3 for like 2 litres of the stuff, pretty disposable if you ask me. I use it in anything apart from the car.

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

I'd love to do that but hesitated as my bike is pretty new (though it's a cheap one). What oil grade does your manual specify for your bike?

Livefast123 · Nearly there... Joined: 14 Mar 2010 Karma :

10w40 and 15w40 are basically the same oils but the 10w is thiner when cold so gives better cold start protection. They both have 40 viscosity when warm.

15w40 used to be a real popular viscosity, nothing much uses it these days as 10w40 has taken over as a multipurpose grade.

You won't do any harm by putting in 10w40
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czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Thanks so much for this tip. The savings will really add up, with the frequent oil changes I have to do.

Seb

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Just one thing though. Do I have to match the API SF specified in my manual? That property doesn't seem so common in the mass market motor oils.

Seb

Livefast123 · Nearly there... Joined: 14 Mar 2010 Karma :

Frequent oil changes = Long engine life Thumbs Up

Just make sure you clean the oil strainer to.
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weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

API SF is obsolete so you won't find any. However, API specs are backwards compatible, so the newer ones are suitable for use in place of the preceding ones.
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Livefast123 · Nearly there... Joined: 14 Mar 2010 Karma :

Just stick with bog standard morrisons / tesco's 10w40 and you'll be fine Thumbs Up

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Current ride - Yamaha MT-07

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Hope you don't mind me continuing this topic?
A bit of websearch shows a wide range of opinions on using car oil in bikes. The one specific problem flagged up is that car oil reduces friction too much, which can cause clutch slip as bikes use wet clutches. From the sounds of it though, don't think any of you who use car oil seem to have experienced this. As my 125 is low power I'm a bit less worried but just want to hear of everyone's experience.

Seb

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Used car oil in bikes loads of times without any problems. Including fully synthetic car oil.

Only time I have had clutch issues with car oil in a bike was after it was tuned quite substantially. It also slipped on new clutch plates and bike specific oil.

In theory the oil specs are backwards compatible but not always. The newer specs do have more friction modifiers. And ironically with the latest ones they are not as effective (the older friction modifiers were not friendly to catalytic converters, and the replacements are not as effective).

All the best

Keith
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Livefast123 · Nearly there... Joined: 14 Mar 2010 Karma :

The only time this will happen is if you buy a oil with friction modifyers like Castrol Magnatec or high spec fully synthetics etc.

I used to run my 125 pit bike on Tesco's bog standard 10w40 for years and never had a problem with it.

Here's a page of bike oils just to give you an idea - https://www.opieoils.co.uk/c-782-10w-40-engine-oil.aspx

Personally on a 125 with frequent changes I would stick to a bog standard 10w40 from the supermarket.
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cb1rocket · World Chat Champion Joined: 30 Jan 2010 Karma :

10w 40 for the win, as others have said its a basic bike and basic engine, its not going to cry with 10w 40 in the bike. Don't pay too much attention to the spec, its an obsolete standard so don't worry. Just get asda/tesco/morrison 10w 40 or castrol GTX 10w 40 oil and away you go!

weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

Livefast123 · Nearly there... Joined: 14 Mar 2010 Karma :

I've never had a problem with any of my engines, gearboxes or clutches using car oil. My Chinese pit bike took years of merciless thrashing being run on Tesco 10w40 and never had a problem then I sold it to a mate and it's still going strong.

It may be true if you have a the latest GSYR 84v Turbo but then if you had a Ferarri then you wouldn't run it on Tesco oil....would you Confused

I'm only running my GT250 on Castrol Evo as Opie had it dirt cheap.
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P. · Red Rocket Joined: 14 Feb 2008 Karma :

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

I think the way car oil is ok for some bikes (low powered) but not for others (anything else) probably explains why there's so much differing opinion/experience. I'd definitely be safe with car oil with my Kymco Pulsar.

Seb

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

czakal · Nitrous Nuisance Joined: 11 Apr 2011 Karma :

Hello people,
In another twist I found out that 20w50 oil is extremely cheap (£6 for 4.5L)

https://direct.asda.com/Smart-Price-Oil-4.5ltr/001010129,default,pd.html#descriptionSection

But it's probably too different a spec from the 15W40 specified for my bike. I'll stick with the somewhat more expensive 10W40 (the bike manual interestingly states 15W40 only; the warranty manual states 10W40 or 15W40).

Seb

MinhDinh · World Chat Champion Joined: 01 Jan 2005 Karma :

P. · Red Rocket Joined: 14 Feb 2008 Karma :

weasley · World Chat Champion Joined: 16 Oct 2010 Karma :

To be fair, I have 19 years' experience in engine oil product development, technical support, marketing and now technical training. There are, in all modesty, few on this forum more knowledgable in oil technology.

However, on the rest of biking, I am an enthusiastic amateur and definitely not out to undermine or usurp any heroes or oracles!
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~~Yamaha XJ600 | Yamaha YZF600R Thundercat | KTM 990 SMT~~ | BMW F900XR TE