180 vs 120 oil pumps

3C/3CL 7mm : 7,8 liters/minute
1000 Jota/1200 9mm : 10 liters/minute
RGS 10mm : 15,6 Liters/minute
"New" production 10 mm: about 10,8 litres/minute (actually quite variable depending on the manufacture).
 
Interesting, that's the first time actual capacities I have seen listed. I thought that RGS came with 9mm pumps. Lots of talk about 10mm being a great mod back in the day, quality is a big question from this.
 
I did not know that a Jota and the 1200 have a bigger pump than a 3C or 3CL?

So in 1976, the first year of the Jota, Laverda said the current pump is not big enough and we are going to make it bigger. But we are not going to put the bigger pump in the 3C/3CL. That makes no sense especially with the 1200's as they were always low performance touring bikes.

And as most Jota's in the USA were dealer built from 3CL's, they are not gonna have the bigger pump.
 
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1200ts said:
I did not know that a Jota and the 1200 have a bigger pump than a 3C or 3CL?

So in 1976, the first year of the Jota, Laverda said the current pump is not big enough and we are going to make it bigger. But we are not going to put the bigger pump in the 3C/3CL. That makes no sense especially with the 1200's as they were always low performance touring bikes.

And as most Jota's in the USA were dealer built from 3CL's, they are not gonna have the bigger pump.
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I don't think so
 
Just a note on oil pressure. Let’s not try to compare a Laverda engine with a plain bearing car type engine. Plain bearings generate and need oil pressure to keep the crank and other plain bearings such as the camshafts from touching. The oil pressure is generated by the oil pump delivery exceeding the oil leakage past the bearing shells and the rotating elements. A loss of oil pressure is almost always catastrophic for such engines. Such engines also need an oil pressure relief valve.

Laverda engines have rolling element bearings on the crank and elsewhere. Rolling element bearings only need about 1% oil to lubricate with the other 99% generally for cooling.

The Laverda engine needs and will happily run with very little oil back pressure and any pressure generated is from restrictions due to the oil galleries, camshaft plain bearings, oil cooler, oil pipes and oil filter, (if fitted).

The biggest weakness, IMHO, is the gearbox output stub shaft plain bush that receives no oil pressure and is dynamically loaded in 1st to 4th gears. Top gear is a 1:1 is a straight drive through so no differential motion. (Note: Some of the racers used needle (rolling element) bearings for this very reason but on a machine running in top gear for long periods, such needle bearings could brinel. The design is just poor.

The freewheeling gears in the gearbox also have plain bushes but spin under no load and are stationary (so no differential motion) once in their gear, so generally get enough oil.

So, Laverda engines do not rely on oil pressure but do benefit from oil flow. That oil flow also helps with cooling. So, a larger pump would not be a bad addition as long as the back pressure generated from such a positive displacement pump does not rise so high that the crankcases and pipes etc get hydraulically overstressed as there is no oil pressure relief valve.
 
3crider said:
Just a note on oil pressure. Let’s not try to compare a Laverda engine with a plain bearing car type engine. Plain bearings generate and need oil pressure to keep the crank and other plain bearings such as the camshafts from touching. The oil pressure is generated by the oil pump delivery exceeding the oil leakage past the bearing shells and the rotating elements. A loss of oil pressure is almost always catastrophic for such engines. Such engines also need an oil pressure relief valve.

Laverda engines have rolling element bearings on the crank and elsewhere. Rolling element bearings only need about 1% oil to lubricate with the other 99% generally for cooling.

The Laverda engine needs and will happily run with very little oil back pressure and any pressure generated is from restrictions due to the oil galleries, camshaft plain bearings, oil cooler, oil pipes and oil filter, (if fitted).

The biggest weakness, IMHO, is the gearbox output stub shaft plain bush that receives no oil pressure and is dynamically loaded in 1st to 4th gears. Top gear is a 1:1 is a straight drive through so no differential motion. (Note: Some of the racers used needle (rolling element) bearings for this very reason but on a machine running in top gear for long periods, such needle bearings could brinel. The design is just poor.

The freewheeling gears in the gearbox also have plain bushes but spin under no load and are stationary (so no differential motion) once in their gear, so generally get enough oil.

So, Laverda engines do not rely on oil pressure but do benefit from oil flow. That oil flow also helps with cooling. So, a larger pump would not be a bad addition as long as the back pressure generated from such a positive displacement pump does not rise so high that the crankcases and pipes etc get hydraulically overstressed as there is no oil pressure relief valve.
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The only gear box problem I've had in over 40 years of Laverda use is a plain bronze bush , 3rd gear?, that wore through.
Paul
 
Paul, I bet if you checked that gearbox 1st motion shaft where the stub runs it will be worn. Maybe they all run quite happily worn? Also, time does not wear, mileage in 1st to 4th does. Anyway, I / we are going off topic!
 
The only gearbox bush that doesn't seem to wear is 1st. gear layshaft. Strangely, the bush with the least issues was replaced with a needle bearing around 1976, which also necessitated a new mainshaft to suit.

All other bushes wear merrily, loads of clunky 'boxes out there just waiting to push the 4th. mainshaft gear through the upper case. Seems to me gearboxes are neglected just as much as electrics... they're only attended to once something goes wrong. But, wtf, as long as the orange glistens in the sun. :rolleyes:

Back on topic;

It's not "Jotas" that got the larger oil pump! The larger pump was introduced with the 1200 and then fitted across the range, continuing into the MkII engines.

Wot's a fuckin' "Jota" anyway?:rolleyes:

piet
 
My 3C has done 163,000 miles (261,000kms) and besides the stub shaft bush, the gearbox under gear bushes are original.
 
3crider said:
My 3C has done 163,000 miles (261,000kms) and besides the stub shaft bush, the gearbox under gear bushes are original.
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Could well be, but they will all be at (or probably over) their upper wear limit. One of the many things that 33 years working on them professionally has taught me. When were they last inspected and actually measured?

Factory wear limits are on the generous side, they are not beneficial for gear tooth wear and possibly a reason for the large amounts of pitting that occurs in these 'boxes. Collapsing mainshaft 4th. gear cogs are not unknown.

750 and triple gearboxes are largely identical save for a few ratio differences, pretty much bulletproof in the 750 but getting on to marginal for the triples. The MkI/II triple close-ratio cluster is altogether a far stronger affair that wears a lot less.

piet
 
3crider said:
Paul, I bet if you checked that gearbox 1st motion shaft where the stub runs it will be worn. Maybe they all run quite happily worn? Also, time does not wear, mileage in 1st to 4th does. Anyway, I / we are going off topic!
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I can't decide if I wait for it to blow up or pull it to bits and give it a once, or twice, over.
Paul
 
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