Would you go for fully synthetic rather than semi?

What are the pros and cons of semi synth, compared to fully synth?

Depends on what type of clutch you have- dry or wet -
My Dakar has a multi-disc oil-bath clutch, mechanically operated and I use Silkolene semi-synth whereas the R1200GS has a single plate dry clutch hydraulically operated- I use a Castrol fully synthetic in that.

It is the additives in some of the fully synthetic oils that can cause wet clutch bikes to slip. I do not know what type of clutch the Africa Twin has.

I have the same 650cc rotax engine in my X-Challenge (and same clutch) and use ONLY full synthetic oil. (have done since the 10,000km mark)

As long as you use a motorcycle specific synthetic oil rather than a car synthetic oil, you will not get any clutch slip. A motorcycle synthetic oil is, after all, specifically designed for wet clutches!

The BMW manual says only that they do not recommend synth oils ONLY for the first 10,000k. I now have 50,000k on my engine, had it pulled apart a couple of weeks ago to check the head, and the mechanics actually asked me if it was a new cylinder. After 50,000k it still had that factory honed look.

For whats its worth, I took the advice of an excellent bike mechanic and use only Motul 300V (double ester) ... its expensive (10 quid a litre in the UK), but you have a several thousand dollar investment and you pour thousands more of dollars of fuel into it over its lifetime. There is only one thing that protects it from wear all its life, and that is the oil. Spend a couple more bux and get a good oil.

Oilman ... is this your site?

Motul 300 V 4T Factory Line 10W-40 Racing lubricant for race bikes 100% Synthetic – Double Ester

If so, I shall be buying form you in the near future.

__________________

That's us. Good post and well put

Cheers
Guy

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

Nice post Oilman.

I'm using full synthetic in my VW diesel and BMW car and have just switched over to synthetic in my R1200GS after the 10,000 km recommended by BWM. My R100GS has had nothing but dino oil in the engine and mostly synthetic in the transmission. The reason I stuck with dino oil is that I thought it would be more practical to do more frequent oil changes in developing countries where synthetic is not readily available. What would you suggest for a trans-Africa journey? Run synthetic as long as possible and then swap out to whatever is locally available, carry enough oil for a change half way down or simply run dino oil from the start, changing as often as practical?

I think we've all heard stories of synthetics causing more oil leaks in an older engine that has grown up on mineral oil. What is the current state of affairs with synthetics? Would putting synthetic in my 230,000 km R100 cause the pushrod tube seals to start leaking?

__________________
Ekke Kok

'84 R100RT 141,000 km (Dad's!)
'89 R100GS 250,000 km (and ready for another continent)
'07 R1200GS Adventure 100,000 km (just finished Circumnavigating Asia)
[SIGPIC][/SIGPIC]

www.ekke-audrey.ca

This is why I like the info that comes through Horizons - people are driven by the necessity of high mileages and the inconvenience of cost. A perfect situation to find out, practically at least, what works and what doesn't.

The average annual mileage of motorcycles in the UK is something like 1 or 2 minor service intervals and model ownership is probably a couple of years. So it stands to reason that the average post about oil/observed failure on any given forum has such a biase due to low mileage experience as to render its validity entirely questionable and highly influenced by the statistical 'bathtub' curve of mechanical failure (e.g. bad day at the factory etc.) than any real difference between one motorcycle oil and another.

What do you lot think? I sense an 'elephant in the room'.

__________________
Find out details of my 2011 trip to Siberia on a lightweight dirtbike:
www.brighton2expeditions.co.uk

The stories about leaking seals are based on older synthetics, not modern ones, so no need to worry about that. The only other reason for a synthetic to leak more is that if the engine has not been particularily well looked after and there is a lot of wear. If the synthetic is thinner than the mineral oil, there may be some leakage.

If you are worried about that, go for one of the hydrocracked synthetics, something like the Silkolene Comp4 or Motul 5100 as they are highly refined and modified mineral oils.

Cheers

Tim

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

The more synth you have, the better it is, surely ?

I remember attending a seminar held by Shell about motor oils and from what I remember (it was a few years ago now), synthetic oils are pretty much better in every way than mineral oils. Obviously, apart from cost.

I always use semi-synth as for me its the best compromise between cost and efficiency.

__________________
Did some trips.
Rode some bikes.
Fix them for a living.
Can't say anymore.

Yes, I would go for synthetic over mineral, mainly becuase they are better, but not all synthetics are synthetic in the true sense of the word many are modified mineral oils sold as synthetic.

Cheers

Guy

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

Thanks - I didnt know that semi was classed as mineral.

Can you tell me this? - if I buy a cheaper m/cycle oil with the correct JASO/SAE codings, will it be as good as an oil twice the price?
In other words, is brand important? Can an oil be inferior if the codes are right?

Depends, yes mainly with oils you get what you payfor so an oil twice the price is likely to be better.

Also think of it this way, one oil may just be good enough to meet a JASO spec, another oil can also meet that spec but also exceed it by a long long way, but there is now spec to show this it will just show up as meet the same JASO spec.

Cheers

Guy

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

Here's a bit more info on the topic from our friend John Rowland, the chief chemist at Silkolene....

"
Before we get into details, the first thing to realise that there is no chalk and cheese difference between mineral and synthetic based oils. After all, the chemical compounds which make mineral engine oils so much better are themselves synthetic. Synthetic lubricant bases are stepwise improvements on mineral oil, with more desirable properties and fewer undesirable ones.

The second important point is that there's no one thing called 'synthetic'!

There are several different types of synthetic lubricant, and to say something like: 'the Supergrunt XXR must have a full synthetic' is meaningless unless the 'expert' explains what sort of synthetic he means.

Equally, to imply that dreadful things will happen if the 1970 Hardley-Ableson Bluegrass is run on anything other than Pennsylvania mineral is ridiculous. It may not need a 2007 synthetic, but it isn't going to come to any harm if the owner uses a 2007 synthetic. The most basic type of synthetic is really a special mineral oil.

Known as 'hydrocracked' bases, these are made in oil refineries by putting certain types of mineral fraction through special processing, so they cost more than the usual mineral types but not much more. They are useful because they resist evaporation at high temperatures. Although used for years for genuine technical reasons, they are now popular with marketing men because the magic sexy word 'synthetic' can legitimately be printed on the label without spending much on the oil inside the can! Yes, all low-cost 'synthetics' contain anything from a few percent to 20 percent (i.e. 'semi-synthetic') of special mineral oil.

Using fairly simple chemical compounds or gases from oil refineries or other sources, it is possible to 'synthesise' or build up tailor-made lubricant molecules which have very desirable characteristics, such as great resistance to cold, heat, evaporation losses or excessive thinning as they get hot. These are the true synthetics, and the two that are used in engine oils are PAOs (poly alpha olefins) and esters. Neither is cheap!

PAOs are related to mineral oils, and are the ideal carriers for all the chemical compounds used in mineral oils. Because they do not gel at very low temperatures, all genuine 0W-something oils have to be based on PAOs to pass the 0W test at a sub-arctic -35C. Esters were originally made for jet engine lubricants, and to this day all jet oils are ester-based. Although similar in performance to PAOs, they have a valuable extra trick: they are good lubricants and help to protect metal surfaces.

As 0W- and 5W- grades are not usually recommended for motorcycles, perhaps the best all-round oil is a 10W/40 shear-stable semi-synthetic with some ester content.

Esters help with transmission and valve train lubrication. 100% fully-synthetic oils are actually quite rare, probably because they are very expensive to make, and even more expensive to buy.

Even so, an ester / PAO with a very shear stable multigrade polymer is the ultimate oil for high output engines that are worked hard, which means racing.
"

All good stuff

Cheers

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

In Europe, provided the price hasn't been pushed up by shipping an "average" oil 5000miles from the West coast of the USA, you do get what you pay for. The best motorcycle oils are made in the more developed European countries, but low price buys the cheap 'modified mineral' synthetic and not much of it, with a poor multigrade polymer. As is so often the case, quality does follow cost.

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944

Thanks for posting all this very interesting info. I, for one, appreciate it.

My Honda asks for a minimum SG quality oil. I found a 10/40 supermarket semisynthetic motorcycle oil which is rated SJ - which is above this minimum. This oil costs 4 euros (£3-ish) a litre. But I don't know if it contains the ideal additives mentioned by the Silkolene man. He suggests a semisynth, but of quality. How do I know it's quality? It seems the answer is cost.

I'd better start hunting for another oil? Do we get value for money from the big names, or are they cashing in on a name?

Problems problems!!!!

Well, with oil you get what you pay for and it's what's not in the oil that matters as addative packs vary in quality too. Many oils are made to a budget because in many applications it does not matter, afterall "any oil is better than no oil".

The problems tend to start with wet clutches and many cheaper oils (mainly car ones as opposed to proper bike ones) do not contain the correct additive pack and may contain friction modifiers which may cause slippage in the wet clutch.

If your bike has a wet clutch go for a bike oil that carries the correct JASO spec as it's designed for Japanese Motorbikes.

These are Japanese and International stanadards for Japanese bikes, I would personally always use a proper bike oil, more stable and contains the correct ingredients.

http://www.opieoils.co.uk/c-773-motorcycle-oils.aspx

A semi-synthetic for ordinary road use and a fully synthetic if modified, used hard or off the road.

Cheers
Simon

__________________
Use the code HORIZONS and get 10% Club Discount
http://www.opieoils.co.uk/
sales@opieoils.co.uk, 01209 202944