Which motor oil is the best for laverda 750 sf1??

Multigrade mineral oils have long chain polymers added, such as EVA (ethylene vinyl acetate). At low temperatures these molecules curl up tightly and so don't impede oil flow. So the oil can flow more easily at low temperatures.
As the temperature increases these molecules uncoil and entangle with the oil molecules, thereby increasing viscosity.
Oil shared with the gearbox has a very hard time as the cutting edge of the gears shear the oil so the viscosity reduces as the long chain molecules get chopped up.
That's one of the reasons why it pays to change oil regularly on our bikes.

Not sure of the chemistry of synthetic oils but I assume it is broadly similar. The manufacturers claim much longer usage time before replacement so maybe they have found a way to avoid chain scission by the gears. Even if I was using synthetic oil in my Laverda (which I'm not) I would still want to replace it more regularly than 10,000 miles or so.

I usually end up replacing the oil after 1000 to 1500 miles. Sometimes even sooner.
 
Grant said:
Multigrade mineral oils have long chain polymers added, such as EVA (ethylene vinyl acetate). At low temperatures these molecules curl up tightly and so don't impede oil flow. So the oil can flow more easily at low temperatures.
As the temperature increases these molecules uncoil and entangle with the oil molecules, thereby increasing viscosity.
Oil shared with the gearbox has a very hard time as the cutting edge of the gears shear the oil so the viscosity reduces as the long chain molecules get chopped up.
That's one of the reasons why it pays to change oil regularly on our bikes.

Not sure of the chemistry of synthetic oils but I assume it is broadly similar. The manufacturers claim much longer usage time before replacement so maybe they have found a way to avoid chain scission by the gears. Even if I was using synthetic oil in my Laverda (which I'm not) I would still want to replace it more regularly than 10,000 miles or so.

I usually end up replacing the oil after 1000 to 1500 miles. Sometimes even sooner.
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+1 (bigthumb)
 
Embossed on the dipstick on all 180 triples are the words use 'Total GTS or Total BOL D'OR 4T' this is SAE20W/50 oil.  The same is quoted in all Laverda handbooks that came new with the bikes.

What was good enough then is good enough now or are we saying that the manufacturer got it wrong?

Any good 20w/50 standard oil will do the job in these old roller bearing engines.  All this high tech, rocket science, super silicone, highly expensive stuff you can buy is a total waste of money putting in these old clunkers.

  Change the oil every 1500 miles and clean the oil filter every 6000 miles the engine will then outlast you.
 
We use Penrite Oil, A Better Class of Oil
One we chose is their mineral based oil, non synthetic and only has 1.49% Sulphated Ash by mass  ???
reminds me of the old Pennzoil that was around for years until Shell took them out

Penrite MC-4ST 15W-50 is a premium quality mineral engine oil designed for use in motorcycles. It
uses an advanced formulation to provide the best balance of power retention and wear protection.
Penrite MC-4ST 15W-50 meets the requirements of API CG-4/SL as well as the performance requirements
of JASO MA.

Application
All four stroke motorcycle engines that require SAE 15W-40 or 15W-50 engine oils.
Suitable for use in four stroke motorcycle engines with wet clutches.
Can be used in other petrol and diesel engines in cars, 4WDs, generators and agricultural
equipment.

Customer Benefits
      Extends engine life by reducing formation of high temperature engine deposits.
      Reduced oil consumption due to the combination high quality base oils and high operating
temperature viscosity.
      Penrite?s Extra Ten provides greater engine protection at operating temperatures compared
to SAE 15W-40.
      Full zinc additive technology to maximise protection and minimise wear under all conditions.
      Reduces clutch slip.

Industry Specifications

API CG-4/SL                                JASO MA
TYPICAL DATA
Density at 15oC, kg/L    0.875
Viscosity Index              113
Cold Cranking Viscosity, cP at -20oC    5,582
Zinc, Mass %      0.148
Phosphorus, Mass %  0.135
Sulphated Ash, mass % 1.49
Base Number    10.8
 
Grant said:
Not sure of the chemistry of synthetic oils but I assume it is broadly similar.
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Ah, no :o.  'tis quite different.  I quote oil guru, George Morrison:

"To make a 20W-50 API rated synthetic oil, we start out with a 50W base stock and (essentially) do ? nothing.

This is because, when full synthetics are cooled, they do not thicken, as mineral oils do.  Same when heated; they retain their viscosity and do not thin.

Water behaves similarily: it only change its viscosity when it reaches boiling or freezing point. In its liquid state, water maintains its viscosity.  In the same way, a full synthetic base stock is very, very temperature stable.  Which is one of the major positives for synthetic based lubricants: they provide the film thickness at higher temps, yet allow easy start-up.

So no viscosity index improvers are needed with this oil.  And the advantage of this is that we avoid their downside, namely that they shear and are subject to load shock.

Remember: The whole API XXW-40 rating program was, and still is, geared to multi-viscosity mineral oils. So a paradigm shift in thinking is required when considering Group IV or Group V synthetic chemistry.

For example: a 10W-40 mineral based oil will be a solid at around 20 degrees below zero F.  Yet the synthetic Mobil 1 Racing 4T still flows freely at 40 below zero F!"

That's one reason for using synthetic oil: it doesn't change viscosity with temperature = no VI impovers = no destruction in the gearbox.  Still gets fouled up by clutch wear and combustion blow-buy, mind; so you can't leave it in for ever (despite what some people might think ...  :-X)
 
alan james said:
... or are we saying that the manufacturer got it wrong?
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No, but oil technology has moved on a bit ...  8).

That said, I know what you mean, Alan, when you say:

alan james said:
Any good 20w/50 standard oil will do the job in these old roller bearing engines.   Change the oil every 1500 miles and clean the oil filter every 6000 miles, the engine will then outlast you.
Click to expand...
 
I suppose the factory assumed normal ambient temperatures for Europe, but if used in more extreme conditions (way below zero) then perhaps the oil quoted by them would not be ideal.
But maybe they also thought that folk wouldn't use the bikes in mid winter.
 
Grant said:
I suppose the factory assumed normal ambient temperatures for Europe, but if used in more extreme conditions (way below zero) then perhaps the oil quoted by them would not be ideal.
But maybe they also thought that folk wouldn't use the bikes in mid winter.
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And I suppose the factory couldn't see into the future and anticipate improvements in lubrication technology!!!! Funny people.

I think this 'Dino' oil is shorthand for dinosaur, sort of the way crude oil is formed (organisms falling to the bottom of a basin, becoming trapped with earth movements/sediment and then being cooked underground in a pressure vessel for thousands of years).

Oh, in my experience I can barely detect the difference between a C3 bearing and a bearing with standard clearance. They aren't THAT loose.

This has been the best oil thread yet, we have the answer in all those thousands of words. I have my own opinion which ones though!!!! It looks like there is a fair amount of duff information swilling around masquerading as fact.
 
SimonR501 said:
Oh, in my experience I can barely detect the difference between a C3 bearing and a bearing with standard clearance. They aren't THAT loose.
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exactly, difference is in microns
 
I always understood that C3 bearings had the same "installed" running clearance as normal bearings.

They are just designed for the outer race to be a tighter fit in the housing than normal. This crushes the outer bearing race to the correct running clearance.

Cheers,

Rob

 
Just compared some 750 sump filters.

The 1969 American Eagle had a very fine brass gauze.

The 1974 GT had a very course wire mesh.

I suspect the change was due to high viscosity oil not getting through the fine gauze.

I once installed a fine gauze filter in the oil tank of my Ariel Square Four (dry sump) and coincidentally used a clear hose to the pump feed.

On a cold start I saw huge bubbles or slugs of air being sucked into the pump. The oil could not flow fast enough.

Changing back to the original coarse wire mesh removed that problem.

Cheers,

Rob
 
I am really enjoying this oil thread.....seriously. Never knew it was so complex and the SAE and synthetic explanations were
very interesting.

I actually use Halfords 20/50 classic because I was advised to look for 20/50 API SE. It gets changed every spring at around
1000 - 1500 miles. I hope that is good enough. I buy Harley oil for my Harley because I have to call in for the filter and gear oil. Synthetic for the others (Aprilia, Ducrappi, Trumph)
because that's what is says in the books.

There you go...I have imparted my entire knowledge of oils onto an oil thread  :)  and in one paragraph. 
 
Basketcase said:
I always understood that C3 bearings had the same "installed" running clearance as normal bearings.

They are just designed for the outer race to be a tighter fit in the housing than normal. This crushes the outer bearing race to the correct running clearance.

Cheers,
Rob
Click to expand...

You could certainly do that, however I believe the extra clearance is there to accommodate fast rotating speeds and temperature differentials.
 
And I found out that Aussie Penrite mineral motorcycle oil for our old bangers is available in the Sepp, quite a bit more expensive than in Oz but comparable with Motul/Repsol. Makes me happy! :D :D
Thanks Red!!

Ken
 
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