Oil for Crankshaft Bearings

hochkoenig said:
But as bigger a Bearing, more Friction is in it. I think that the Big bearings survive its because coincidentally the Bearings are Oversized and the RPM on Lavs are quite slow.
They constructet all just by Feelings and experiences, nothing calculated here.....
8)
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Yep, it's called overbuilding - and lucky for Lav (Breganazanian) twin owners, there's more of it in our agriberthas than you'll find in a triple  8)
 
"The big end pin not only has to carry......Added to that are the centrifugal loads imposed by the bottom half of the con-rod flying around in a circular path."
Aha! So that is ehy the big end is bigger.
 
Well i dunno..will ask my MEng son.Did like tge oil lube assisting grooves in the phosper bronze bushes put in when the crank was fully redone...seems like a nice idea though whether necessary or not who knows?😁
 
I now don't think of them as being a good idea Nick, the oil hole at the top gets the oil right where it is needed, and even forms a tiny reservoir and those spiral grooves might even create a stress concentration point, plus undesirable "edges" the next one gets plain small ends as factory
CLEM
 
Tippie said:
"The big end pin not only has to carry......Added to that are the centrifugal loads imposed by the bottom half of the con-rod flying around in a circular path."
Aha! So that is ehy the big end is bigger.
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Hm, yes its a good Question, why the Conrods have differend Diameters, maybe it looks mor professionel then? ;) But serious, I remember the KTM Factory struggeld with bending Pistinon Pins.... (What they thought, but how can you proof....) thats why they start to use not "Pipes" but full round Material as Pistonpins! (At the LC4)

Anyway, I think Laverda was looking if the Engine would be usefull for a Agrar Machine also or something...
 
hochkoenig said:
But as bigger a Bearing, more Friction is in it. I think that the Big bearings survive its because coincidentally the Bearings are Oversized and the RPM on Lavs are quite slow.
They constructet all just by Feelings and experiences, nothing calculated here.....
8)
Click to expand...

Oh dear... ::)

Of course the engineers in Breganze calculated before they built.  That sort of thing may have happened in the Stone Age, but since the beginning of the industrial revolution, engineers have had to save pennies were ever they could, therefore careful planning and calculating preceeds any construction, if the exercise is to work as planned (and they were to earn a $ or 2).  Experience plays a part, but is only a small part of mechanics.  Just about everything can be calculated beforehand, computers make this a doddle these days (I still had to learn that with formulae, a calculator, pen and paper).

If KTM had to revert to solid piston pins after breakages, somebody seriously fucked up in the first place.  But bikes these days are throw-aways, once knackered they are often not rebuildable (or it simply isn't viable), so it doesn't really matter much. :D

We should be glad the boys of Breganze did things the way they did, otherwise our machines would have gone the way of the Dodo long ago, or wouldn't have even attained the popularity they enjoy today.  I think planning future repairs and overhauls into the intial draft is the key here, a matter of course when producing agricultural machines.

rant over...
piet
 
Piet
A couple of years ago, I had a spit at one of our Italian machine manufacturers, when, we couldn't remove an M10 bolt, which located a rod end (that needed a 1 turn adjustment) from it's location. A 12mm aluminium beam was in the way and all the bolt needed was about another three turns to get it out.

Almost a days work of stripping the entire area, to remove the bolt and make one turn on the rod end wasn't appreciated. (liken it to removing a Laverda triple motor from a custom frame to get the cam cover off ;) )

They came back, and said they hadn't thought of the issue at design and mfr.  ::)

They now have a suitable hole through the aluminium plate, to remove the bolt. 

 
chrisk said:
Piet
A couple of years ago, I had a spit at one of our Italian machine manufacturers, when, we couldn't remove an M10 bolt, which located a rod end (that needed a 1 turn adjustment) from it's location. A 12mm aluminium beam was in the way and all the bolt needed was about another three turns to get it out.

Almost a days work of stripping the entire area, to remove the bolt and make one turn on the rod end wasn't appreciated. (liken it to removing a Laverda triple motor from a custom frame to get the cam cover off ;) )

They came back, and said they hadn't thought of the issue at design and mfr.  ::)

They now have a suitable hole through the aluminium plate, to remove the bolt.
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Find those sort of issues quite often on modern vehicles.  While assembly lines require a definite procedure (to fulfill the 50xxx units/day), disassembly is not even considered!  Ever tried changing a headlight bulb on a VW Golf V?  Fuckin' nightmare, not only technically challenged owners need to consult their local dealer/workshop.

piet
 
As a mechanic you come across it constantly, having to remove this before you can get to that, then discovering that you also need to remove the 'that' before you can remove the 'this' and so on ... incredibly frustrating. When you come across something that's been really beautifully thought out it is a very good day. My #2 SF with a frame that came from a wrecker 30 years ago has a lovely big dimple about 4cm x 2cm whacked into the rear frame tube that joins the main frame with a ball peen hammer where the DPO just couldn't quite fathom how to get that big old battery out. Factory design flaw - remove the airbox to get the battery out? Not sure, but a smaller battery certainly would have helped avoid having to live with the result of lazy, halfwitted POs!

As many on this forum have said, many a Laverda's problems are due to the wrong kind of human intervention.
 
I'm very happy I still have my Taunus-Cortina. If I first remove windscreen washer container and air filter then after that it has almost no single part that can not be easily taken off. Access to clutch needs removing gear box and even that can be easily done with garage jack and two jack stands.

Edit: typos

 
sfcpiet said:
Find those sort of issues quite often on modern vehicles.  While assembly lines require a definite procedure (to fulfill the 50xxx units/day), disassembly is not even considered!  Ever tried changing a headlight bulb on a VW Golf V?  Fuckin' nightmare, not only technically challenged owners need to consult their local dealer/workshop.

piet
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Something like this are also on old JAP Bikes! Ever tried to chance a Airfilter on a KAWA Z 900 ? NOT POSSIBLE
Thats why Italo Bikes only (not only reason, but...)
 
I've always found Japanese bikes well engineered and easy to work on, although sometimes a little complicated when you're dealing with multiple cylinders and valves.

One thing I like about Jap bikes is that all the little bolts holding stuff on the frame nearly always have captive nuts or tapped threads, so you don't have to bend your arm in 3 places to get a spanner in behind whatever you're trying to remove. Almost never see that on an Italian bike. Every bolt has a nut on the other end. I'm aware that having a separate nut allows the use of nylocs, but it still annoys me when it's impossible to get at. I've been known to weld nuts onto the frame for the really inaccessible or frequently removed ones.
 
Dellortoman said:
I've been known to weld nuts onto the frame for the really inaccessible or frequently removed ones.
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I've done that MANY times, Cam. Especially if it's something I need to remove on a semi regular basis. On that front, I hate speed nuts (common on cars) - they always seem to strip out too easily.
 
Piranha Brother 2 said:
Not sure about triples, but the twins have an oil drain from the front right head stud to the base of the barrels and then through a hole drilled down to the cavity between the crank main seal and the RH main bearing. On an SF I rebuilt recently the Signor Luigi forgot to drill the drain hole, but there was zero evidence that it had mattered - I drilled it for safe measure, and it wasn't easy getting the angle right!

Conrod big ends are under loads more load ( :D) and thus require a positive and reliable oil feed.
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Must be a little Hole only, otherways the Oilpressure for the Camblocks gone, right? Can not imagine where do Drill a Hole, not much Stuff left there....
You have a pic maybe?
 
Piranha Brother 2 said:
Not sure about triples, but the twins have an oil drain from the front right head stud to the base of the barrels and then through a hole drilled down to the cavity between the crank main seal and the RH main bearing. On an SF I rebuilt recently the Signor Luigi forgot to drill the drain hole, but there was zero evidence that it had mattered - I drilled it for safe measure, and it wasn't easy getting the angle right!

Conrod big ends are under loads more load ( :D) and thus require a positive and reliable oil feed.
Click to expand...

The drain to the RH main is to transport lube to the freewheel needle bearing.  Apparently, not much oil mist travels through the spinning main bearing, but the needle bearing spins all the time the engine is running and would otherwise be quickly starved.  The drain allows a little extra to reach the freewheel, excess simply drains back through the main bearing.

piet
 
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