MAIN BEARINGS FAILURE, MUST CHANGE

Hey weed,

Can I ask what balance factor you went for?

All the best,
Simon

Thanks for the info weed- much appreciated.

I like the different approach to the balance weights.

Simon- he states he used 66 % as balance factor.

weed

"When removing the counter-balance the crank should be re-balanced to a factor of 70% plus or minus 10% (Lineaweaver) a spacer can be made to replace the bearing or just use the inner race"

a nquote from the doc. i think you did a superb job fella! well done!

i'm holdoing my d...my copy of mr irvin's book now. had it 20 years so it's getting a second read in that part.

BTW: anyone else reading in who feels they can offer stats on the following measurements that would be great:
crank journals
inside dia and
outside dia of bearings
id of bearing housing
ask weed to borrow his arbor....
run out of crank

regards

Taffy

AUSBERG said:

Simon- he states he used 66 % as balance factor.

Click to expand...

Thank you.

Simon

i've bumped this in an effort to get finnberg and maybe if he needs it: jgo to measure the stuff mentioned already:

anyone else reading in who feels they can offer stats on the following measurements that would be great:
crank journals
inside dia and
outside dia of bearings
id of bearing housing
ask to borrow an arbor....
run out of crank
endfloat of crank

regards

Taffy

Simon said:

It is very rare that the right hand main goes - it always seems to be the left.

Simon

Click to expand...

Unlucky I guess...

Vegard,

Nice photo - or not so nice if it is your failure, should I say.

That looks like spalling across the entire width of the roller track (a statement of the obvious, perhaps). Does the spalling continue around the entire race or just that section you've shown?

What do the other components from that bearing look like now? Did the flange crack?

What were the other side bearings like, including the c/b?

All the best,
Simon

Looks familiar.

this the other type of main bearing failure we were talking about regarding finnbergs post.
the flange of the bearing is ok but the roller running surface is stuffed.
how many other people have had this type of main bearing failure?
what size motor is this 450/550/650?
what oil were you running ? how many hours?
..weed..

it's a 650SM weed. that picture sould start to tell us a lot if we work it out?

for instance, there is metal spauling even on the flywheel face it seems to me
and even on the flywheel behind in the photo (top r/h corner).

notice also that the spawling stops just before going out of sight on both the
top and the bottom of the journal. so we can see the full extent (i trust) of the damage.

the crank runs clockwise as we look and you can see the big end pin.

how does only one area start spauling and why at that spot?

so as they say on 'a question of sport' "what happened next!"
i think you're talking hot slivers of hardening flying about here.

regards

Taffy

Here is a pic of mine.

I was not riding my bike when this happened, I was letting someone else ride it.
They were flogging it for about 12 laps on the ice at high revs. When they finally came in I noticed it was louder so I decided to let NSMAN rip her apart.
I believe it was a combination of things that led to this. It could have been my several runs on the gravel at 165kph last fall.
I was using either Amsoil or Rotella, I can't remember which.

you're having me on! that's a 4,000 year old greek toilet! the carving on the wall is beautiful! the lip at the bottom is for your feet and you just hang your arse over the edge. a kinda communal bog!

picture of the inner race please? :lol: :lol: :lol:

regards

Taffy

good imagination taffy,
just wish you would share it around what you're on..
with a name like ..weed.. who am i to talk..
..weed..

My main went on my 06 FE550 after doing 140kph for approx 8 seconds(near, but not redline ). I used Motorex 15-60 synthetic & changed every 5 hrs( with filter).Went bang 19hrs after rebuild.Hard to tell but I reckon it went bang on deceleration, just as I let go of the throttle. Only a slight vibration at first made worse by me riding the bike trying to isolate the vibration. This would also support Simons theory that more load at exhaust tdc. If you do it long enough, would it heat one part of the race so the split second it scratches, all further damaged continues from the initial failure ?

I know nothing about pulling berg motors apart, just interested like evryone else. 8) Great minds at work here, thats for sure.

how does it pick a certain point to start spauling? is that coz the rollers get squeezed tight and there is a massive heat build up at say 2 o clock on the bearing and created on every stroke? at the same point everytime? attacking one point until it over heats and starts to pick up?

are we tlking about a massive load in one spot that no matter the quality of oil and bearing that without lubrication AND THAT OIL IS ALSO A FLUSHER AWAY OF HEAT - are we talking about heat in one spot? a classic example are the engines that go at idle having only just been started. but that's because the flakes and spawl cooled and re-welded itself somewhere else around the bearing.

with the spauling you get oscilation/vibration in the crank which means it must pick up at the trailing or leading edge of the hardened surface every few 'moments' and then we start knocking shoulders off the inner race etc. bits go into the other bearings, the flakes (red hot) go up and stick to the bore only for the piston to come down over the top and start graunching the flakes into the cylinder wall.

people like geoff duke and barry sheene could feel one main going in a four cylinder engine so we should be able to also feel a difference.

but what starts the very first spauling and break up of the hardened surface? the bearing must be locking solid for a moment and the crank keeps spinning so there is your problem? the bearing probably locks and releases, locks and releases. meantime there is such a tight fit on the crank that there is massive heat generation if the bearing so much as moves for a split second let alone a 'lot of time!' around the crank.

i'm going to suggest that the bearing only spins on the crank after the initial problem. so what is the initial problem? what makes the whole roller bearing lock solid and then allows the crank to spin seperate from the inner race?

oscilation? is this due to a flexi crank assembly? if so why not always on the left and NEVER the right? (due to the c/b assembly).
does the oscillation allow the tips of the rollers at the ends to get over heated and break down? the oscillation would mean that although the rollers always continue around the housing the heat build up is in one place. weeds cases were spot on (we trust!) so that leaves poor tolerances in the housing and journals from the factory as well as any other weaknesses. but i don't think it's the alignment of the cases?

WE COULD DO WITH THE POSITION OF THE OUTTER RACES BEING NOTED BEFORE THEY ARE KNOCKED OUT OF THE CASES IN THE EVENT OF A CRANK FAILURE (vegard? jgo? etc etc)

we could normally rely on the oil to take the heat away by washing over these hot spots?

i also thought about this: why does the right bearing go at all? and then i thought - well no oil can 'huff' or 'blow' through the bearing at all. zilch. no cooling effect, less lubrication.

meanwhile, over on the left we have a huge window for the oil to blow through - what if that was smaller and the oil had to blow through the bearing thereby of course helping it?

also, have we got dodgy oil pumps?

also, how come orangeberg has never been back and now enginehardwear and ...... and ......

are our teams being knobbled by a greater power? a hidden force? is this like the movies?

"you dirty rat...."

the plot thickens

it'll be simon next. he's a trouble maker. o sheeete! he hasn't posted here for a while either.....

that only leaves m

regards

Taffy

:twisted:

Just keeping my eye on things....

I understand that for most people a bearing failure is a bearing failure and that is what they post, but we mustn't get the issue any more confused than it already is....

So here are a couple of thoughts:

1. There is no substantiated causative link between the right and left hand bearing failures at present;

As weed said earlier there is a difference in the failure.

On failure right hand side shows spalling, the left doesn't but as yet there is no evidence to suggest that the spalling on the right causes the failure on the left or vice versa. I certainly think the evidence is to the contrary, like it or not.

What this means is that one failure happens over time (even if fairly rapidly), the other doesn't (a bit like the old single race counterbalancer bearings that ate themselves for lunch, in a fraction of a second, bang).

I would very much want to know the ratio between the different types of failure, because as it stands it is nowhere near 1:1.....

2. In order to understand the spalling somewhat more, it would be extremely helpful to know where the spalling occured compared to crankshaft rotation - i.e. was it around tdc, bdc , 90 degrees from tdc or whatever because in that case we could at least work out whether there is a relationship with crankshaft balance, thus primary or secondary forces;

From vegard's picture is looks like it is from about 10 degress after top dead centre to a few degrees before bottom dead centre. It is therefore not at the absolute peak loading of the crank.

3. The spalling, as suggested, might point towards a lubrication issue. What I would like to ask therefore is if what I consider to be blatantly stupid advice to reduce the oil level but a hundred ml or so is being followed by anyone who has had the spalling type failure (would you be man or woman enough to admit it?);

My recommendations is that you should never ever reduce the amount of oil in your engine. On a 650 you would be well advised to increase the oil content slightly, particularly if you are using it at high engine speeds.

I had some more thoughts but I've forgotten what they were so that'll have to be it for the moment.......

All the best,
Simon

PS - peak load at tdc on the exhaust stroke is not my theory, I'm afraid, it is commonly accepted engineering fact :wink:

Simon said:

From vegard's picture is looks like it is from about 10 degress after top dead centre to a few degrees before bottom dead centre. It is therefore not at the absolute peak loading of the crank.

Click to expand...

i would hold my horses there. first of all the spalling is more like 20 or even 30d from tdc and bdc ON THE CRANK. however the point is you don't know where in the rotation the spalling started?

it's easy and probably likely to think it's a crushing force on the face that spalled but it could be that the pressure was elsewhere and showed up where you see it.

a question to ask SKF is; "does spalling move with the direction of rotation or against it?" if you know the answer then good - let us all know.

as for the low oil levels well i don't see any references in the doc from the SM crowd giving out worldly advice and certainly none since i started it to correct what might be an error. as always, if you know something - -pass it on!

that's what UHE is about.

regards

Taffy

Taffy said:

ON THE CRANK. however the point is you don't know where in the rotation the spalling started?

Click to expand...

:roll:

Taffy said:

as for the low oil levels well i don't see any references in the doc from the SM crowd giving out worldly advice and certainly none since i started it to correct what might be an error. as always, if you know something - -pass it on!

Click to expand...

I have been giving out this info for many years. Even Dale concurred with me on a couple of occasions too - but hey who am I to talk :wink:

I still maintain that it is blatantly stupid to recommend using less oil in an engine that has so little oil in it to start with - whether in the doc or not.

I've said it many times and I'll continue to say it....... whether anyone listens or not

All the best,
Simon

well given your attitude....

probably not actually.

just to be clear: "where in the rotation the spalling started" means out of the 720d of crankshaft rotation the spalling started - sorry if it wasn't obvious what i meant but there is a genius at work here you know!

regards

Taffy

Hi, I have a FE550 2004. I use my Husaberg only on the racetrack. I have a brearing damage with 24h and 60h. My dealer always use the NJ206ECP bearing. After the second damage, the crank was modified. We use a Special Bearing with more balls. The NTN TMB206.
The diameter of the crank was modified. The press fit was minimized. The reason therefore is:
1. to haven´t troubles by motor assembly 2. to have a floating bearing. With this setting, my Husaberg works 60h without Problems. After the 60h hours, i didn´t have any damage, only a loud bearing because the increased clearance. But now i have found a new bearing generation on the NTN homepage. The Long-Life AS Series (TAB). The TAB bearings last five times longer than the standard type, and twice as long as the TMB Series.

Now I think about to remove the c/b. And use the TAB 2206 with a spacer instead the c/b. If the TMB runs 60h the TAB 2206 should run 100h and more.