synthetic oil?

Originally Posted by jakeblues68

Just noticed Heine Gerricke have a deal on Motul semi synth, oil filter and air filter for £25.
How does that compare?

as seperates I had the oil filter as £7
air filter as £12

that makes the oil £6

Let me know your thoughts.

JB68

Yes, but they don't do this package for the sv

On the point of less friction giving better economy, smoother running and slightly better power, I remember when we used to ride 2-stroke motocross bikes, and we all switched to synthetic in the eighties. One of the things that made us switch was an independent test done on an outboard boat engine (Yamaha 40 bhp). They fitted two tanks, one premixed with mineral 2-stroke oil, the other with Bel-Ray synthetic 2-stroke oil, and a tap that could switch between the two. With the motor fully warmed up, they did 2 runs up and down a lake at full throttle on mineral oil, and digitally monitored the maximum and average revs for the runs. Then they switched the tap to the tank with synthetic oil premixed, and repeated the runs. The average reading showed over 500 rpm higher at full throttle, indicating lower friction levels. They also showed the piston crowns and cylinder heads after a long-term test with synthetic, and they were shining, whereas the control motor (using mineral oil) had a build-up of carbon on both surfaces, enough to scrape off.

I know a 2-stroke is very different, using the pre-mixed oil only for lubrication of the big- and little-end bearings, piston rings, etc. and not the gearbox, but it does say a lot for synthetic.

Jon.

Originally Posted by OF.uk

Yes, but they don't do this package for the sv

Strange, which store are you trying as i got the deal 2 weeks ago in Darlington, Co Durham.

Hi,
I have a 650S K1 (51 reg) with 7K on the clock. It runs ike a dream. I intend to do my own oil / filter changes and this article has been very interesting as I was considering the arguments in using full / semi synthetic oils. Its been really interesting reading the various schools of thought. From my own reasearch I have decided to use Semi synthetic 10/40W but was wondering how often to change it as the oil and filter are relatively cheap. Surely the more oil changes the better - BUT are there arguments agianst this thinking ?

The oil is barely changing colour at the standard service intervals. To me that means to change it any sooner would be pointless. I change the filter everytime because they're not exactly expensive.

Originally Posted by Carsick

The oil is barely changing colour at the standard service intervals.

Mine goes black very quickly and I change every 2500 (semi-synthetic).


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Originally Posted by jonboy

Mine goes black very quickly and I change every 2500 (semi-synthetic).
.

mine is still not black after 4k, also semi-synth up till the last service.
She gets a full service in another 1500 miles, so will let you know how the fully synth got on.

[embee]

Originally Posted by Kev D

.......but was wondering how often to change it as the oil and filter are relatively cheap. Surely the more oil changes the better - BUT are there arguments agianst this thinking ?

no arguments against it, other than you'll wear out the drain plug thread

As Carsick says, if the oil is still looking clean, chances are it's still perfectly serviceable. OK that isn't a scientific test, but the main reason for changing modern oils is contamination rather than degradation. The main wear processes are abrasive from particulate matter, which is usually soot based and therefore associated with blackening, so it's a resonable guide.

Lot's of short journeys, or probably more significantly lot's of cold starts, will tend to accelerate the contamination. Judge how you can extend or shorten the service interval by the type of use you give it.

FWIW I use my SV as a weekend toy, only do longish runs, and only a few thou miles per year, so I just change it once a year before winter when I take it off the road.

My Deauville does rather more miles, and I work on 4k miles oil+filter (it would probably be fine at a lot higher miles, but it makes me feel better). It really is false economy to change the oil but not the filter. Yes the filter will hold a lot more contaminants than it gets in 4k miles, but why mess up nice new oil by putting it through a dirty filter?

Rapid blackening of oil is indicative of short cold runs and possibly excessive blowby, which can be either from high mileage wear or poor break-in procedure (broken rings aside).

Excessively rich mixtures will produce a lot of soot too, so will make oil go black. If you've re-jetted with big mains, raised needles etc, and your oil goes black quickly, you may just have overdone it a bit.

Don't do short runs, the bike's now done 23k and runs fine but (ahem) it's still got the original plugs in which I keep meaning to change . Would that be a possible cause?


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Jonboy,

I wouldn't have thought that would be a problem as surely all that the sparkplug touches is the fuel and anything that it could contaminate is either burnt or goes out through the exhaust anyway.