Oils - 50/50 or Fully Synth

[Taman]

Had a look through previous posts and seems that most people go for half synth oil, but fully synth is recommended. Is fully synth just "higher performance" and half synth is fine for non-track. Should I just go for a good quality version of either? Seems like there's so many to choose from. Local shop has valvoline fully synth - so thought that would probably be fine.

Thanks

[nik_the_brief]

IMHO you're better off getting the cheaper deal and changing the oil more frequently.

Semi-synth is certainly up to the job as long as you don't leave it in there too long. Regular oil changes are one of the most important ways of keeping your engine in good nick.

HTH

[Lost Again]

Did an oil change not long ago and put in 5W30 fully synth because thats what haynes says. Went to the weekender and got told by many people NOT to use this oil. Apparantly it finds its way past pretty much every seal in there including piston rings. True to form my bikes been burning oil pretty well the last couple weeks with the odd bit of plug fouling. Getting replaced tomorrow with some 10W40 semi synth. I've been told it'll be much happier on this. Soon find out!

[Pedro]

Fully synthetic is recommended by Ducat and Haynes but semi-synthetic is absolutely fine and is often recommended by specialists. I use Rock Oil and change it every 2,500-3000 miles.

Ped

[Duncan]

I change my oil every 6000 miles and use the best oil I can put in the bike. That means full synthetic with the highest API rating I can find.

The improvements in oils have meant that an engine like the air cooled twin with its origins in the 1970's and originally with 1500 mile service intervals does 6000 intervals on modern oil.

Car oils are not suitable due to different properties and friction reducers that would affect wet clutches on the smaller engines and they get ruined by gearbox operation. Most car oils will have higher API ratings than bike oils.

Heres the proof of the pudding. My bike has done over 45,000 miles, has only ever needed one shim in the engine doing (at 32,000 miles) and doesnt need topping up between services. Thats full synthetic for you.

For the sake of £10 a time whats the point in economising?

[Taman]

OK - so should I top up my oil or drain and change? Is there any harm leaving old oil in there and going for the easier top it up option?

[Shauns4]

I had a CB125 which did 35,000 miles on Duchams 20w-50 and I doubt it would have gone further on synthetic oil! (it died of rust)

I think the bike manufacturers cover themselves by specifying the best oil from a specific manufacture for reasons we all know. Monster engines are relatively low stressed compared to a japanese '4' so I'm sure a semi-synthetic oil is fine although I must confess i use fully synthetic as i get it for £15 a gallon so its a no brainer.


best to use one oil, keep to it, make sure it gets 'warmed up' and change it regular, the rest is acedemic?


Shaun

[Zimbo]

Fully synthetic is recommended by Ducat and Haynes but semi-synthetic is absolutely fine and is often recommended by specialists. I use Rock Oil and change it every 2,500-3000 miles.

Ped

I use Rock Oil Guardian semi synth as well, used it for years, it's top stuff and at £16 for 4 litres is much cheaper than most as well! Changed every 3000 miles. As my bike is seeing a little more track use at the moment I may use Rock Oil's fully synthetic instead next time, about £23 I think.

[gary tompkins]

It's worth noting that while full synth. may be fine for dry clutch monsters, some members have experienced problems with clutch slip on wet clutch engines. I have heard of this happening on both eairlier carbed 600/750's and later fuel injected 620's, and it may be due to the friction reducing additives in some full synth oils?

I personally suffered from this slipping, when running my own M600 on shell advance full synthetic. After swapping back to semi synth (silkolene) the slip problem dissapeared - go figure ;)

I'd like to add that I've been running the 900ie on Shell advance since new, and after almost 18000 (trouble free) miles plan to continue doing the same.

[OgriUK]

interesting thread this :)
always thought it was best to use fully synth in any bike, but can see why some dont. changed my oil as a matter of course as soon as i bougt the bike(it had 720 miles from new) and used fully synth...will see what mark at bsd recomends as well come service time.
normally change oil halfway between regular oil changes as well... its not that expensive really and is the lifeblood of the engine..

[gary tompkins]

I use Rock Oil Guardian semi synth as well, used it for years, it's top stuff and at £16 for 4 litres is much cheaper than most as well! Changed every 3000 miles. As my bike is seeing a little more track use at the moment I may use Rock Oil's fully synthetic instead next time, about £23 I think.

Zimbo,

I also (on dealer advice) ran Rock oil semi synth 20/50, for the 10 years I had my Morini 3 1/2 sport. The bike had nearly 14,000 on the clock when I bought it and over 62,000 miles :eek: when I sold it. I changed the oil without fail every 2500-3000 miles - important as the morini had no oil filter, just a mesh strainer. Also it had no pressure feed to the heads/valve gear, just splash feed via the pushrod tubes, so quality of oil was critical.

General owners club opinion was that most Morini sports struggled to get past 30,000 miles without a major rebuild, so I think that speaks volumes for both the quality of Rock Oil and the importance of regular changes. Oh and by the way, the bike was ridden hard (they just love a good thrashing) right up until the day I sold it :D

[CK & AK]

AK used semi synth in my wet clutch M750ie after the first service, and we both use fully synth in his 900ie & my M1000. Oil & filters done every 3000 miles :) so, that is between 2 & 4 changes a year for our bikes

C :)

[birchie]

I had a (ssh dare I say it) Honda ntv 600 that I despatched on, I ran that on semi and sold it with 139,000 on the clock all original incl cam chains. Also ran me 748 ( 18,000 no probs) on semi. For my s4r I gave into advertising and tried fully synthetic, it didn't seem to like it returning less than 1,000 mils to a litre of oil. Back to semi now and it doesn't use any.

as said before the secret is to change it often I do mine every 3,000 miles it seems to pay off in the long run. I also use Rock oil Guardian

[Phoenix]

Fully Synth in Max now - did get a iffy clutch for a few laps but thats settled down fine now. Won't be run on owt else now I don't think.

[The Kevlar Kid]

Another thing to understand is how the two types of oil degrade.

When fully synth reaches the end of its 'life' it degrades very very quickly, leaving you with little or no protection in a very short space of time.

This makes regular changes very important.

Normal mineral oil will degrade much much slower, so for those who dont change oil so often, it will ofter protection for longer.

If I remember correctly, 'semi-synth' is actually a mineral oil base rather than as the name suggests 'synthetic' so will perform in a similar way, degrading slower.

I have a presentation somwhere with all this stuff in it from one of the oil companies. If I can find it, I'll post it as it will give a shed load of info.