OIL IN CRANKSHAFT AREA
- Thread starter nsman
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No one seems to know the answer and I have not been able to find it as well.
After some reseach/reading i.e. wading through the SKF and NTN bearing maintenance guides I have gathered some info.
The NJ62 series bearings have a rpm maximun of 11000 rpm but only if they are in an oil bath mounted in the horizontal position.When in the vertical position the maximum for this bearing is less 20% or 8800 rpm but only if the bearing is at least 30% submersed in oil.
With the increased loading of the axial counterbalancer and using maximum RPM for any extended time period there is a possibility that this bearing is being overextended.
It is noted in the guides that bearing life is extended with the use of what is referred to as diester oil.
After some reseach/reading i.e. wading through the SKF and NTN bearing maintenance guides I have gathered some info.
The NJ62 series bearings have a rpm maximun of 11000 rpm but only if they are in an oil bath mounted in the horizontal position.When in the vertical position the maximum for this bearing is less 20% or 8800 rpm but only if the bearing is at least 30% submersed in oil.
With the increased loading of the axial counterbalancer and using maximum RPM for any extended time period there is a possibility that this bearing is being overextended.
It is noted in the guides that bearing life is extended with the use of what is referred to as diester oil.
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I am interested to see where this line of 'questioning' ends up...
Cheers
Mark
Cheers
Mark
Re: RE: OIL IN CRANKSHAFT AREA
Hi nsman, this is only a guess but I would think the only oil to the bearings is what is being fed by the pump regarding the quantity in this area I would think it will be only small as the downward stroke of the piston will clear the sump via the reed valve, but like I said this is only a guess.
Regards
Sparks.
Hi nsman, this is only a guess but I would think the only oil to the bearings is what is being fed by the pump regarding the quantity in this area I would think it will be only small as the downward stroke of the piston will clear the sump via the reed valve, but like I said this is only a guess.
Regards
Sparks.
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RE: Re: RE: OIL IN CRANKSHAFT AREA
I think that what this info is telling us is that there is a design limitation to these rollers.They have made a slight trade off in peak RPM for increased load ratings.It explaines a lot,but really nothing we did not all ready know.If you run a berg engine to its maximum RPM with respect to its cylinder head beathing ability you can damage the engine.This may explain why certain tuners prefer to use balls and no balancer.It also may explain why for the most part enduro riders have little problem in this area and others who live in more open areas where high speed running is possible have issues.
If you ride in the Australian country where you can see for miles and like to go fast the chances are good,if you ride in the eastern part of NA where you never see more than a few hundred yards ahead and engine speeds are in the midrange chances are poor.
The counter balancer can be a benifit when the engine is used as a true enduro mount as in the euro sport and it can be a detriment idf the engine is used for use in the exreme end of this engines RPM ceiling.
If you run supermoto and like to gear it tight you may be wise to use a rev limiter.Fact is it may be a good idea for anyone who wants to explore the extreme end of the rpm ceiling.
Good fuel,proper gearing for the riding conditions and not overreving the engine will pay benifits in main bearing life.
I think that what this info is telling us is that there is a design limitation to these rollers.They have made a slight trade off in peak RPM for increased load ratings.It explaines a lot,but really nothing we did not all ready know.If you run a berg engine to its maximum RPM with respect to its cylinder head beathing ability you can damage the engine.This may explain why certain tuners prefer to use balls and no balancer.It also may explain why for the most part enduro riders have little problem in this area and others who live in more open areas where high speed running is possible have issues.
If you ride in the Australian country where you can see for miles and like to go fast the chances are good,if you ride in the eastern part of NA where you never see more than a few hundred yards ahead and engine speeds are in the midrange chances are poor.
The counter balancer can be a benifit when the engine is used as a true enduro mount as in the euro sport and it can be a detriment idf the engine is used for use in the exreme end of this engines RPM ceiling.
If you run supermoto and like to gear it tight you may be wise to use a rev limiter.Fact is it may be a good idea for anyone who wants to explore the extreme end of the rpm ceiling.
Good fuel,proper gearing for the riding conditions and not overreving the engine will pay benifits in main bearing life.
Re: RE: OIL IN CRANKSHAFT AREA
Gazza, this is what I've being trying to preach but there you go I've always used Silkerlene Pro4 15/50 used it mainly on road race engines never had one failure this oil is designed for this kind of enviroment.
Sparks.
Gazza, this is what I've being trying to preach but there you go I've always used Silkerlene Pro4 15/50 used it mainly on road race engines never had one failure this oil is designed for this kind of enviroment.
Sparks.
just thought i,d do a bit of reseach while the motor is appart.go to weeds gallery to check out crankcase oil volume etc, by the way main crank bearings are splash feed.it would be possible to increase the crank oil level if the overflow rib was built up.
regards weed
regards weed
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Hi weed,
I dont think increasing the oil level is a viable opiion.A design featue of these engines is that the oil below the spinning crank is expelled out of the reed valve assy.This has the effect of less drag on the rotating crank assy,with no oil bath to cause drag.
When you think about it the Berg engine is similiar to a 2-stroke bottom end.This design takes the best from both worlds so to speak,ingenius really!
I dont think increasing the oil level is a viable opiion.A design featue of these engines is that the oil below the spinning crank is expelled out of the reed valve assy.This has the effect of less drag on the rotating crank assy,with no oil bath to cause drag.
When you think about it the Berg engine is similiar to a 2-stroke bottom end.This design takes the best from both worlds so to speak,ingenius really!
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Re: RE: OIL IN CRANKSHAFT AREA
have to agree with this , silkolene is a good product .
sparks said:
have to agree with this , silkolene is a good product .
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Sparks,
New style motor (01 up) is pressure fed to the big end and mains through a crank end feed arrangement. Old style motor was simply splash to bottom end. Oil pump in the 97-00 was only to push the oil through the paper filter. Much better filtering than the old screen, but was still splash. Could thoeretically move the evacuation reed valve lower in the new model pressure fed set up to lower oil friction on the spinning crank since you are not so dependant on splash. Not sure if that was done or not. FWIW, Years ago Dale voiced his opinion to me that he preferred the older oiling system. Heven't had a KTM apart so can't comment on their system.
dan
New style motor (01 up) is pressure fed to the big end and mains through a crank end feed arrangement. Old style motor was simply splash to bottom end. Oil pump in the 97-00 was only to push the oil through the paper filter. Much better filtering than the old screen, but was still splash. Could thoeretically move the evacuation reed valve lower in the new model pressure fed set up to lower oil friction on the spinning crank since you are not so dependant on splash. Not sure if that was done or not. FWIW, Years ago Dale voiced his opinion to me that he preferred the older oiling system. Heven't had a KTM apart so can't comment on their system.
dan
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Seems that what we should be talking about here is that it seems apparent that the main bearings on the new or old bergs are not lubricated in an oil bath as is a conventional 4-stroke..
In the new bergs the oil is pumped through the crank end and out the big end bearing where it is spayed around and into the main and counter balancer bearings and then expelled out into the clutch cover by way of a reed valve assy.
As the bearing manufacturers rate this roller bearing best in an oil bath I wonder if this style bearing is the best choice for the job.
I suspect that it was a compromise for the counter balancer,but I am anything but an engineer.
Since the bottom end is lubricated more like a 2 stroke(as in a oil spray or mist) i wonder if we should consider what size bearing would be best as per a 400 cc 2 stroke.
If nothing else it may shed some light on why things are like they are.
Remember Husabergs are built and sold to be "race ready"competition motorcycles and as such are not meant to be super realiable ALA XL honda.
A long time ago at a Yamaha dealer meeting I had the pleasure to meet one of the Japanese engineers who was on the RD/RZ350 design team.We had had many crank failures on the RZ at usually between 20 and 25 thousand km.When I asked him about this he put his hand on my shoulder and said "RZ made for a good time,not a long time"...
In the new bergs the oil is pumped through the crank end and out the big end bearing where it is spayed around and into the main and counter balancer bearings and then expelled out into the clutch cover by way of a reed valve assy.
As the bearing manufacturers rate this roller bearing best in an oil bath I wonder if this style bearing is the best choice for the job.
I suspect that it was a compromise for the counter balancer,but I am anything but an engineer.
Since the bottom end is lubricated more like a 2 stroke(as in a oil spray or mist) i wonder if we should consider what size bearing would be best as per a 400 cc 2 stroke.
If nothing else it may shed some light on why things are like they are.
Remember Husabergs are built and sold to be "race ready"competition motorcycles and as such are not meant to be super realiable ALA XL honda.
A long time ago at a Yamaha dealer meeting I had the pleasure to meet one of the Japanese engineers who was on the RD/RZ350 design team.We had had many crank failures on the RZ at usually between 20 and 25 thousand km.When I asked him about this he put his hand on my shoulder and said "RZ made for a good time,not a long time"...
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Take a look at many "comparable" engines.
ie FE650 vs LC 4 vs XR650R.
You will soon come to the conclusion that the Husaberg is either
1/ Seriously underbuilt in the main bearing department
OR:
2/ A lightweight, no compromise race engine with longevity a secondary consideration compared to engine weight.
Just like a RFS/CRF etc etc.
BTW, KTM use the same bearings (NJ206) in the 250 SX-F/EXC-F engines at a much higher mean RPM than the average 550/650 could ever dream of. So it would seem that maybe loading/crankshaft/counterbalancer design as opposed to RPM is a bigger factor in bearing failures.
Another point to consider is that more than 1 personr has admitted to sending bikes "out the door" after checking end float and finding it to be below Husabergs recommended minimum specs. It has been documented on this site in one of the many, many main bearing threads.
How can we go looking for faults, if one of the maybe biggest contributable faults is staring us right in the face and we choose to ignore it ???
ie FE650 vs LC 4 vs XR650R.
You will soon come to the conclusion that the Husaberg is either
1/ Seriously underbuilt in the main bearing department
OR:
2/ A lightweight, no compromise race engine with longevity a secondary consideration compared to engine weight.
Just like a RFS/CRF etc etc.
BTW, KTM use the same bearings (NJ206) in the 250 SX-F/EXC-F engines at a much higher mean RPM than the average 550/650 could ever dream of. So it would seem that maybe loading/crankshaft/counterbalancer design as opposed to RPM is a bigger factor in bearing failures.
Another point to consider is that more than 1 personr has admitted to sending bikes "out the door" after checking end float and finding it to be below Husabergs recommended minimum specs. It has been documented on this site in one of the many, many main bearing threads.
How can we go looking for faults, if one of the maybe biggest contributable faults is staring us right in the face and we choose to ignore it ???
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i hear you AUSBERG ....
at the end of the day if it comes down to design what is the solution ?
another thing is , we hear of a lot of failures in aus but very few in other parts of the world .
it would be interesting to know the units sold ,units melted in aus .
'' '' '' '' '' , units cooked in usa .
at the end of the day if it comes down to design what is the solution ?
another thing is , we hear of a lot of failures in aus but very few in other parts of the world .
it would be interesting to know the units sold ,units melted in aus .
'' '' '' '' '' , units cooked in usa .
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After looking at Ausbergs pics and diagram of the KTM engine it occurred to me that we also have to consider the possibility that since the Husaberg engine relies on positive pressure from the downward stroke of the piston to expell the oil collecting in the crank area,that this pressure effect may increase the effectiveness to push the oil from the reed valve as the RPM rises.Since the size of the reed valve does not change during RPM flucuations it may be a compromise so it does not gain oil at low RPM and yet it may be so efficent that it can virtually blow the engine bearings dry at high RPM......whereas the KTM engine has a gear drive sump pump to always ensure a constant RPM to flow rate...
I gotta get out of here before my head blows up!!!
I gotta get out of here before my head blows up!!!
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dsducati said:
Hi guys,
After looking at the RFS lubrication flow schematic ( I'll put it in my gallery later) , the scavenge pump from the crankcase on the RFS simply sucks the oil through a screen and to the transmission- no filtration involved other than the mesh screen.
The 2nd "short" paper filter on a RFS is an apparently finer micron filter than the long one.
KTM & Husaberg share the same "long" paper filter, but the RFS gets filtered a 2nd time through the shorter, supposedly finer paper filter.
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