hard shifting

[Anonymous]

VISCOSITY

THANKS FOR THE REPLY KIM
pPEASE HELP ME TO UNDERSTAND WHAT YOU MEAN BEHAVES LIKE 50 WEIGHT OIL BIT DOESNT GET THICKER
THANKS AGAIN
SCOTTY

[Anonymous]

Hi Scotty,

I'll have a go but it takes a while to write these things out....

Imagine that you have five buckets of oil, all different weights, a 10, 20, 30, 40, 50. The 10 will be quite light, and each will get heavier until the 50 is very heavy.

Now put these buckets of oil over a heater so they heat up to "half hot". They will each be slightly lighter than before. The operating weight of them as they thin out is now 5, 10, 15, 20, 25.

Now keep heating them up to as hot as an engine at full running temperature. They get even more thinner so they are now 3, 6, 10, 14, 20. It might help to write these numbers under each other as they get hotter so you can see the progression.

What we have is a lower viscosity rating for each oil as the temperature rises.

But this is not good for engine oil as we want it to stay the same through the operating range. If we need 20 grade oil so we can actually pump it around the motor without taking too much of the motor's power away, that is what we need. And we need it when the motor is cold or hot.

Trouble is, we put in cold 20 grade oil and it won't keep the thing properly lubricated when it is hot and is thinned down to 6 grade. But if we put in 50 grade oil which works OK when it is hot it is too stiff for us to pump around the motor when cold.

So the oil gurus came up with methods to keep the oil at certain vicosity levels. They do this by combing different length molecules with different characteristics of how they join up with each other. Those stable oils are what we use these days.

But when they did this they wanted a method of describing how viscous the oil was when it was cold and when it was hot. So what we have now is a cold/hot method of describing oil. Forget the W, but 20W50 means at cold it is 20 grade oil - and when it is hot it is still 20 grade viscosity, just as a 50 grade oil would be when that is hot.

They could have just cal
led it 20 grade, but some things like oils that thin radically when hot, and sometimes we need to hold a fairly level viscosity through a wide temp range.

As the Castrol ads say (at least here in Oz), "Oils aint oils".

This might still be a bit confusing. Sorry about that. In people terms we might say something like, "You're pretty normal most of the time but behave just like your father when you get under pressure." This might mean we lose our temper or we cope wonderfully.

When the heat's on, we start to behave differently. So does oil.

I'd better stop before this gets too confusing.

Anyway, what time are you over there? Here in Oz it's 8:50 Thurs night. We got Star Wars II showing 20 hours ago.

Kim

[Anonymous]

oil

Sorry I put yu through that--I just reread the article on "all you want to know about motor oil" that is in the IN THE GARAGE SECTION of our website --plus i was in voice with duncan bone in australia and i have it straight now-- so now i want to see how the synthetic oil ((15 w 50 )) reacts with the shifting thing--I WILL READ YOUR ENTIRE POST TO HELP ME TO GET THE INFORMATION INTO MY HEAD
THANKS

[Anonymous]

You were trying to ready up on oil theory and talk with Dink at the same time? You've got nerves of steel.

Reminds me... It's about time I got myself down to Dink's place before he moves too far north to be within reach.

Kim

[Don Lobacz]

Everyone who has a dragging clutch should check the metal plates for warpage. I bought a bike once that had a dragging clutch and yes, everyone blamed it on the Barnett disks, but it was fine after I got straight metal disks in it. Since they tend to warp into the shape of a bowl, it takes a little effort to check them all thoroughly. If you have a perfectly smooth surface, you are supposed to lay them down on each side and check for a gap with feeler gauges. I prefer to take the whole set of metal disks (as they were arranged in the bike, minus the friction plates) and hold them together like a sandwich. Usually there are 1 or 2 very noticeable gaps in an otherwise tight group: on one side or the other of that gap will be a warped disk. Often, just by rearranging the order of the disks, I can get the gap to disappear (like stacking bowls for the cupboard), and this generally lessens the dragging effect to where it's not even noticeable. Officially, though, you should replace warped disks.

[daveo]

I've had Barnett clutches in both the 750 and 1100 and tried 20-50 once in the 1100, immediately had the shifting problem, changed back to 10-40 the same day, no more problem. The synthetic oils may be too slick for the clutch discs, I've only heard of people using them when the trani oil is seperate from the engine. The newer Kevlar Barnett discs are very smooth and with much lighter springs than the older kits.

[Anonymous]

shifting

Dave from what i have learned in the past few posts, i am noe believing that the oil is the culprit--but i never have trouble with slipping clutches with synthetic oil no mater how i drive the bike

[Anonymous]

After boring my 1100 to 1150 and fitting a tuned exhaust I understandably developed a slipping clutch. After checking all the plates for tolerance I fitted heavy duty springs. I now have an overdeveloped left forearm and no more slipping clutch. I have also found that the shifting has become a little more difficult and have had to keep my clutch well adjusted. I also have the problem, as already mentioned, of chewing through clutch cables. A period on synthetic oil has also sorted any shifting problems.

[redliner1973]

One thing to consider about synthetic vs dino oils, synt's are NOT 'slipperier' than dino oils, just are more molecularly stable, meaning that they will not break down as quick, as the molecules are designed to all be about the same size, vs dino oils that have various sizes, some which dissolve faster, and some that don't. I have run synthetics in several bikes, and cars, and NEVER had a slipping clutch problem. If you want to prove it to yourself, start fresh with a good quality Dino oil, do an oil analysis at drain interval, then fill with synthetic and drive the same as you did before, and do another analysis at the same interval oil change...you will notice a difference......

[Anonymous]

not slipperier??

why does my bike engine run noticably cooler with synthetic oil?????

[redliner1973]

Because the dino oils you were using were breaking down faster, resulting in more friction. Syns don't break down no where near as fsat or much hence the engine runs cooler.

[Anonymous]

Oil Breaking Down

THEN WHAT YOUARE TELLING ME IS THAT AS SOON AS I START THE ENGINE AND WARM IT UP-JUST AFTER CHANGING MY OIL AND FILTER AND USING CASTROL 20-50 DYNO OIL THE DYNO OIL BREAKS DOWN AS SOON AS THE BIKE WARMS UP AND THIS IS WHY THE OIL TEMPERATURE STAYS IN THE SAME SPOT FOR THE NEXT 2000 MILES--((THATS WHEN I CHANGE OIL))-IF THIS IS THE CASE THEN THIS CASTROLL I AM USING IS JUST ANOTHER GARBAGE PRODUCT ??????????????????????? IT'S CONFUSING TO ME 8O

[redliner1973]

Are you using 20W50 Synthetic also?

[redliner1973]

OK, try this out...Part of the problem of dino oils is that becasue of their refined nature, they are composed of molecules that differ greatly in size. As the oil flows through the system, the small moles tend to flow in the centre of the stream, whilst the large heavy ones adhere to metal surfaces where they create a barrier to heat transfer from the componant to the oil stream. also, uniformly sized moles, like synthetics slip over each other much easier than the non-uniformed sized dino molecules. Kinda like if you could roll marbles over one another, easy if they all were the same size, but harder if the sizes were different. this non-uniformity is another factor to added friction in dino oil, hence your hotter temp when using them, and cooler temp when using synthetics. remember that motor oil does almost 50% of the cooling, you can see why Dino's are 'hotter running' than synthetics. Hope that makes it alittle clearer

[moto_dan]

Tim,
In your experience which synthetic do you suggest for our GS's? Another question. Would you happen to know the best operating tempature range for engine oil?