MAIN BEARINGS FAILURE, MUST CHANGE

The drill holes in the crank pin and crank flywheel are supposed to line up.If they dont line up the parts used are/were incorrect.I had a very early fe450 that used a crank pin/flywheel arrangment that parts were not available for.The replacement part (fe450 crank pin) would not line up with the flywheel hole.I had to (in my case )convert it to a 470 to make it serviceable(SEM ign)..

this is an early 450 nsman.

the 3-4mm drilling stops just before it breaks through into the hollow big end chamber, in what is left the oil squirts through a hole probably only 0.4 - 0.6mm.

as far as the arbor goes we have decided on one that will be shapped like apollo 11 with the base of the shaft resting on the outer race of the bearings shoulder. i may even persuade simon (my engineer) to place a thread on the shaft that goes through the first bearing.

as far as internally mic'ing the bearing housings goes well he fears there aren't many people or tools that are going to tell you this measurement accurately down to microns and i can see his point!

because i've only stripped two huseys i haven't seen some of these internals before but i've been tootling along all this time under the apprehension that the bearings sat in steel shoulders in the cases (like mine does) but i see that they are now directly into the cases themselves. the right case catches oil above the main and feeds it down and outside the bearing to go into the bearing - all by gravity. there is nothing on the left.

still can't recall anything about a snapped crank bar my own report from 12-months ago!

regards

Taffy

Broken crank pins are rare in any engine.From my experience they are usually the result of poor assy or the result of detonation or other undue engine stress. Do you know if the engine has the std 450 Berg piston in it?

Taffy said:

the big end pin disappears into each flywheel yes? well the end that goes in the left flywheel has a drilling in it and it snapped across there. it therefore snapped the big end pin but just a few mm into the left flywheel.

the odd thing about the drilling is that it is about 3mm wide and stops before it actually reaches the hollow chamber of the big end. it's purpose therefore isn't absolutely clear!

the con rod has been rubbing hard against one cheek and you can see the circular inprint of the con rod sideface.

tomas (engine hardwear) have you checked that the con rod aligns with the middle of the bore?

regards

Taffy

Click to expand...

Hallo.
Yes i have checked, due to that i opened a engine this weekend that had a broken innerring on the left side main bearing.
Yes, the crank is in the same position on a std engine as on ours, checked with the liner and piston out, just with the crank and case.

I do have some additional info that i have recieved from SKF Sweden this week.
The main bearing that comes from KTM with following bearing no: NJ206EC/C3 VC025, we have not got the exact description for what the "VC025" is.
According to SKF the inner ring is stronger and more resistent against dirty oil.
The ones we buy we cant get with this specification from SKF just the standard ones, we will now use the OEM from KTM, even if its more expensive.

Regards
Thomas

nsman

yes the standard piston.

he is a trained mechanic although nowadays his job is to run the garage and not weild a spanner.

regards

Taffy

Enginehardware,

Thank you for the updates, they're very interesting. Interestingly the new main bearing you mention is installed in Finnberg's engine where I saw the designation with interest.

Regarding the experiences of your riders, I'm most interested in that their issues are not due to vibration from the removed counterbalancer but from the change in gyro effect. I don't want to pry inappropriately and I'm sure you've already been through all this stuff, but can I ask how long they gave it before deciding they didn't like it? It's just I know how notorious riders can be about changes to bikes and not giving themselves enough time to work throught the new thing. In other words, they sometimes don't give things a chance and it's more of a psychological thing! :wink:

My own experiences on riding c/b installed bike versus non c/b installed bike back to back is simply a change in feel on dirt or low traction areas of the circuit where the non c/b installed bike would spin up much easier and not provide the acceleration (but that engine had a proper high comp piston in it also). However this problem at least could easily be resolved by moving the rear wheel forward in the swingarm thus adding weight to the rear of the bike.

I know it's getting slightly off topic but I'd be interested to hear your views and experiences.

All the best,
Simon

Simon said:

Enginehardware,

Thank you for the updates, they're very interesting. Interestingly the new main bearing you mention is installed in Finnberg's engine where I saw the designation with interest.

Regarding the experiences of your riders, I'm most interested in that their issues are not due to vibration from the removed counterbalancer but from the change in gyro effect. I don't want to pry inappropriately and I'm sure you've already been through all this stuff, but can I ask how long they gave it before deciding they didn't like it? It's just I know how notorious riders can be about changes to bikes and not giving themselves enough time to work throught the new thing. In other words, they sometimes don't give things a chance and it's more of a psychological thing! :wink:

My own experiences on riding c/b installed bike versus non c/b installed bike back to back is simply a change in feel on dirt or low traction areas of the circuit where the non c/b installed bike would spin up much easier and not provide the acceleration (but that engine had a proper high comp piston in it also). However this problem at least could easily be resolved by moving the rear wheel forward in the swingarm thus adding weight to the rear of the bike.

I know it's getting slightly off topic but I'd be interested to hear your views and experiences.

All the best,
Simon

Click to expand...

Hallo.
The riders that didnt like the increase of gyro used the bike for a full weekend of testing, since the riders only compete in Swedish championship Súpermoto we have no fact regarding Enduro or MX. The positive part was that the engine felt more rapid in rpm range, but we are now using a very light crank so the feeling is the same as without c/b.
Just less gyro force.
We didnt have so much vibration as we was expecting, much due to a very light piston we belive, we tested with a stock flat piston from Wossner which was 100gr more heavy and we got alot more vibration. We use the 2006- Elko(OEM) piston.
We had a bike up at Husaberg R&D in orebro Sweden on the dyno and we had alot of power and torque, so we know that the stress on our main bearing is a problem.
I had some photos sent out to Taffy with our main bearing problem, i dont know if he have them in his gallery( i dont have a gallery of my own).
Anyway since we always use 2 or more bikes on a test weekend we get some diffrent feel and messurment each time and basicly we all aggree that up to now we prefer a engine with c/b, light crank, bigger valves, soft valvesprings, camshaft from KTM, dual exaust, drilled carb, ect ect.
But what we have noticed is that the negative peak that comes from breaking when the wheel is jumping/bouncing are very high compered with positive powerpeak when opening the throttle full. Using a slipperclutch reduces it alot, and we get more hours out of the mains after installing the slipperclutch.

Its just difficult to explain how the riders feel the effect of less or more gyro, in swedish i can but i lack some master degree in english, sorry.
Regards
Thomas

I use a STM slipperclutch but had main bearing failure at just 14 hours.
May I ask what sort spring you use? If you have also an stm.

husa

Enginehardware said:

Its just difficult to explain how the riders feel the effect of less or more gyro, in swedish i can but i lack some master degree in english, sorry.
Regards
Thomas

Click to expand...

Thank you Thomas, that is enlightening. No apologies needed.

If you ever happen to be in the mood and have the time to go into it in moredetail, by all means send me a PM in Swedish - I'm fluent in the language and even if I haven't lived there in a few years I speak it regularly with my mother who lives in Dalarna :wink:

My first ever excursion on two wheels was at about the age of three sitting in front of my uncle on his classic early 1900s Husqvarna on gravel roads in Norrland

All the best,
Simon

I believe that slipper clutch really will decrease peaks when breaking with engine,
and that breaking effect is really strong in such bikes as bergs,big 4 stroke single cylinder engine
bikes.These peaks are bad for gears,but also to the mains, like mentioned earlier by enginehardware.

Can anyone tell from where I could get that kind of clutch used? e-bay?

Funny detail in my berg's gearbox is KTM logo in gear wheel(see gallery).

guess what after 20 engine hours..........

as i eat humble pie simon.
main bearing failure number 2 happened on the weekend.
ist was with 6206 9 ball on the drive side, back in 2006
this time with 20mm wide nj2206 on the drive side.
the ntn nj206 with the thinner inner shoulder on the flywheel side was in good condition.
the rollaway nj2206 with the thicker shoulder was smashed off,i've just put a photo of it in my gallery.
we ask the question why?
the crank must me suffering from side loads from left to right rather than the other way around,otherwise the weaker shoulder on the nj206 should break off 1st.
this time last year i was running a nj2206 on drive side with a 6206 9 ball on the flywheel side.
i ran this set up for 6 months without a problem(with more engine hours on the motor)
so whats the difference?
(1) the 6206 9 ball on the flywheel side rather than a nj206.
(2) the spacer i made up was different this time,with less support for the shoulder this time,i put a photo in my gallery of that one as well if anyones interested.
the orginal spacer i made up was out of an old 6206,it has a wider diameter (more support for the shoulder.
question time!!
has anyone had a shoulder smashed off from the nj206 on the flywheel side?
enginehardware,you say you support the shoulder of the main bearing inner with a support washer,have you had any failures doing it this way?
..weed..

why should everyone have to address a problem that Husaberg should clearly have fixed by now.....we as the customer should not have to be trying to reinvent the bike itself to make it reliable..

husaracer said:

I use a STM slipperclutch but had main bearing failure at just 14 hours.
May I ask what sort spring you use? If you have also an stm.

husa

Click to expand...

We use Suter Racing and Husaberg OEM.
Suter is less expensive, works well.

Regards
Thomas

[quote
has anyone had a shoulder smashed off from the nj206 on the flywheel side?
enginehardware,you say you support the shoulder of the main bearing inner with a support washer,have you had any failures doing it this way?
..weed..[/quote]

We ´have had some broken bearings before on the 644cc cranks flywheel side, but after the washer system we have not seen the problem.
On the 628cc crank, flywheel side should not be a problem due to it have a support for the inner ring flange/shoulder.

Regards
Thomas

why should everyone have to address a problem that Husaberg should clearly have fixed by now.....we as the customer should not have to be trying to reinvent the bike itself to make it reliable..

falls on deaf ears...

well i think we agree with you 100% faktor! you enter these things hoping to find a cure fairly shortly and then the time and effort is worth it! the kudos to the guy that can cure the problem is super cool status as well.

you see, it's a man thing!

it's at times like this that what we know is pooled and things you'd half forgotten are recalibrated in the noggin again! enginehardwear change their bearings with great regularity as do others but finding a long term cure appears to be alluding us all.

right now i don't have an idea what's wrong but if we all add a bit we can at least narrow it down a bit. i collect my arbor tomorrow, set of cases and can add a bit more. unfortunately, from the engine i'm covering i can only talk of a snapped crank.

weed, first of all that's a ****** bit of bad luck and so few hours.
how many hours/was it the same NJ2206?
the arbor i'm collecting will have some way of pinning the arbor back and square to the outer race so that we really are square.
Q: what was your axial thrust on this rebuild?

tomas
it would be nice to have a photo of your support washer and the material you made it from perhaps? please.

now a couple of "left of field" ideas:

the 650 early and late cranks? the 550 cranks? what are they made from and how? cast? or forged?
we've never discussed the tolerance of the primary drive gears? can we discard these being incorrectly oversized on the basis that the r/h/s main has gone at times as well?

also: although dale has mic'd up the inner diameter of the mains housing it appears still that we have little on it.

regards

Taffy

popup said:

as i eat humble pie simon.
main bearing failure number 2 happened on the weekend.
..weed..

Click to expand...

Sorry to hear about the failure weed.
My thoughts (for what they are worth)
Seems the .2mm endfloat was not enough ?.
Perhaps next time use a wider spec- like Husaberg have been doing to help fix the problem maybe??.

popup said:

the crank must me suffering from side loads from left to right rather than the other way around,otherwise the weaker shoulder on the nj206 should break off 1st.
..weed..

Click to expand...

Is the inner ring on the Rollway NJ 2206 EMAC4 carburised?? If not, perhaps the flywheel side 206 has a stronger material spec than the clutch side 2206……??

One thing to keep in mind in regard to inner ring flange support is the 644 cranks only have a very small support area on the flywheel side….only about 36.2mm in dia.
This would not offer the inner race on that side flange support either- not much more than the O.D. of the inner race of a counterbalancer bearing on the LHS, about 35.1mm.

But seeing as how Thomas has had the inner flange cracking issue too and has fixed it with more support area for the thrust flange on the clutch side is telling us something.....

Looks like your next spacer might be the same OD as the thrust flange diameter?? I know mine will be .

Taffy said:

also: although dale has mic'd up the inner diameter of the mains housing it appears still that we have little on it.
regards

Taffy

Click to expand...

Mine measured up at 61.92mm - now thats tight considering the bearings 62.00mm OD !!
They didnt exactly fall out when the cases were heated :wink: ......

regards
AUSBERG

you've told me that just in time. my engineer MAY be prepared to look for something to a few thou!!!! that's absurd ausberg! it is meant to be 61.998 to 62.000mm so yours is about 32 times oversize.

if there was flex in the crank weed, would it be good to use a copper washer? that way if there is flex it will peen in at the outer edge but remain the correct width say nearer the centre. it will also give back a lot of information afterwards.......

all the metals here are too hard!!!!!!

regards

Taffy

Its a man thing ....


Nah for me its a money thing .....


Costing way to much for now...