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Switching to synthetic oil

freemountain2010-05-17 15:46:20 +0000 #1
Thinking about switching my bike to synthetic oil but I've read many conflicting views, whats the consensus on a 25 year old machine thats been on dino its whole life. I've read that seals can start leaking, and the better detergent properties can remove deposites that are currently helping seal rings, lifters etc. If swapping oils may cause me to lose compression/have to deal with leaks I'm gonna not gonna chance it. So should I keep whats currently working or switch it up?
Son of Lars2010-05-17 16:03:00 +0000 #2
Motul 5100. My 18 year old Gixxer loves it. And she's got 164000km on the odo. Uses less than half a litre between oil changes, unless I really beat her up. 5100 is a class 3 "semi synthetic" ester based oil. When I switched to a full synthetic class 4, she hated it, and drank a litre in 1000km. That was ipone, not Motul though. I just stick to 5100, and change it every 3000km. Go for it.
dasein2010-05-17 15:55:53 +0000 #3
Quote:

Originally Posted by Son of Lars

Motul 5100. My 18 year old Gixxer loves it. And she's got 164000km on the odo. Uses less than half a litre between oil changes, unless I really beat her up. 5100 is a class 3 "semi synthetic" ester based oil. When I switched to a full synthetic class 4, she hated it, and drank a litre in 1000km. That was ipone, not Motul though. I just stick to 5100, and change it every 3000km. Go for it.

If I remember right, the ester base has way stronger detergent properties than the PAO base. I have heard that one can run the Ester base Motul full syn almost as an engine flush, and then change it fairly soon, as it will be loaded up in an older engine. Then run what you like.

That Motul stuff is so expensive, but I can see the nice benefit of using a super strong detergent in an older engine, provided you keep an eye on how quickly it loads up when you first make the change.

Some high mileage diesel guys run a (group 4) ester base oil as a clean up periodically while running carbon based oil regularly.

That group 3 base stock is still very clean stuff (with very low wax content), but it will not have the film strength, viscosity range, detergent, dispersal, super hot and cold temp properties of a group 4 oil.

I run Esso Extra XD-3 0W40 in everything I own (two diesels and two bikes).

Full group 4 oil (PAO base stock) at $23 for four litres. If you find it works for you, it is very cheap compared to the Motul oils, and it is a very, very good oil. I like to just have one container around the shop.

But you might leak, or burn it, or any other oil like that. Then try something else.

You sure aren't going to hurt the bike by cleaning it up with a crankcase pass of an ester base group 4. Just be sure to note how quick it gets black: day one, and you should change it by the end of the week. But you will appreciate it when it comes time to take the valve cover off. A clean motor is a happy motor.

From wikipedia:

Instead of making motor oil with the conventional petroleum base, "true" synthetic oil base stocks are artificially synthesized. Synthetic oils are derived from either Group III mineral base oils, Group IV, or Group V non-mineral bases. True synthetics include classes of lubricants like synthetic esters as well as "others" like GTL (Methane Gas-to-Liquid) (Group V) and polyalpha-olefins (Group IV). Higher purity and therefore better property control theoretically means synthetic oil has good mechanical properties at extremes of high and low temperatures. The molecules are made large and "soft" enough to retain good viscosity at higher temperatures, yet branched molecular structures interfere with solidification and therefore allow flow at lower temperatures. Thus, although the viscosity still decreases as temperature increases, these synthetic motor oils have a much improved viscosity index over the traditional petroleum base. Their specially designed properties allow a wider temperature range at higher and lower temperatures and often include a lower pour point. With their improved viscosity index, true synthetic oils need little or no viscosity index improvers, which are the oil components most vulnerable to thermal and mechanical degradation as the oil ages, and thus they do not degrade as quickly as traditional motor oils. However, they still fill up with particulate matter, although at a lower rate compared to conventional oils, and the oil filter still fills and clogs up over time. So, periodic oil and filter changes should still be done with synthetic oil; but some synthetic oil suppliers suggest that the intervals between oil changes can be longer, sometimes as long as 16,000-24,000 km (10,000–15,000 mi).
schmii2010-05-17 17:06:15 +0000 #4
Quote:

true synthetic oils need little or no viscosity index improvers, which are the oil components most vulnerable to thermal and mechanical degradation as the oil ages

Best part. dino oil has the wear at 2-3k that synthetic has long after you're supposed to change it.

If you shift gears in the oil you can't beat synthetic.

Just avoid energy conserving stuff and you're gold.
dasein2010-05-17 16:52:08 +0000 #5
Quote:

Originally Posted by schmii

Best part. dino oil has the wear at 2-3k that synthetic has long after you're supposed to change it.

If you shift gears in the oil you can't beat synthetic.

Just avoid energy conserving stuff and you're gold.

+1 on the energy conserving stuff. They contain friction modifiers that might harm your clutch.

And you should pick a diesel grade (CH4 or CH5 usually marked "heavy duty").

These will have extreme pressure additives that will make your gearbox happy.
Goatrider2010-05-17 16:05:41 +0000 #6
Finally, an oil thread that makes sense. Keep in mind, if you buy your oil from down south, its the only market where an API class III can be called 'full synthetic', so watch what you buy.
freemountain2010-05-17 17:26:48 +0000 #7
Thanks,I'll be getting this stuff south of the border so I'll definitely read the bottle closely. Dasein, If the oil goes black after a day do I change it after a week cause its full of crap or because I don't want to overclean the motor in a single oil change? I've aleady pulled off the valve cover and everything looked clean.
kivyee2010-05-17 17:11:29 +0000 #8
You won't lose compression, but your seals might leak. That, and potentially higher oil consumption, is the only "danger" in using synthetic oil in a high mileage bike. If you think the oil system has been generally very clean, then I'd say go for it. If not, be careful, because once leaks start, going back to Dino oil will likely not help as the deposits have already been cleaned off, and the only way to reseal is to put in new seals.

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