Counterbalancer bearings: definite thread?

[tourist]

Hi all,

Rode a 550 last summer and I still can't get it out of my head, so I'm doing my homework before purchasing one We've had a really good summary thread on the main bearings recently: viewtopic.php?f=5&t=18085

Some local riders have warned against counterbalancer bearing failure. How common are these failures in the '04-'06? '07-'08 bikes? From reading up on the CB/bearings, it seems that there are a few preventative options:
- Remove the counterbalancer. Don't rebalance the crank.
- Remove the counterbalancer, rebalance the crank. Better - but more work of course.
- Use the double-bearing counterbalancer assembly that appeared in the '07 models. (It doesn't seem to be unanimously considered better to use a counterbalancer. Opinions vary. AFAIK the drawback is that to switch to the double bearing counterbalancer you have to get the entire counterbalancer assembly, which isn't cheap.)

Can we say today that these are the definitive fixes - and all of the fixes?

Any information most well appreciated! Thank you!

 

[tourist]

Followup questions - Are there any assembly gotchas or tolerances/clearance that need to be checked carefully to not trigger premature CB bearing failure? If a CB bearing fails, is it a symptom of a niggling failure elsewhere? Are there any other modifications that have the side effect of relieving stress on the CB bearings?

 

[Taffy]

nothing wrong with any of the CBs over the years. I guess a wobbly crank would phuq 'em up but other than that I don't think the doggie deserves a bad name......

Taffy

 

[tourist]

nothing wrong with any of the CBs over the years. I guess a wobbly crank would phuq 'em up but other than that I don't think the doggie deserves a bad name......

Taffy

Thank you!

Wobbly crank as in something that ought to be cleared up with known-good bearings and careful assembly and good tolerance checks in general? Or wobbly crank as in a bad crank?

 

[bushmechanic]

if you remove the CB on a stock 628 the balance factor will be very close to 62.5 which is what you want for a balancer less husaberg engine

I haven't measured it accurately but its coming up in the next build

i don't miss the CB at all Dale lineaweaver referred to it as a clattering piece of junk, weed found the same when he removed his.

also .. without the CB you can put a stonking great 20mm wide roller main bearing straight into the case with no mods to it

 

[tourist]

if you remove the CB on a stock 628 the balance factor will be very close to 62.5 which is what you want for a balancer less husaberg engine

I haven't measured it accurately but its coming up in the next build

i don't miss the CB at all Dale lineaweaver referred to it as a clattering piece of junk, weed found the same when he removed his.

Thanks!

My next mission: Learn how to calculate the CB-less balance factor for the 550 engine. Should be educational!

 

[ned37]

i pulled the cb from my '02 650 back when it was my dual sport bike. impression was: quicker revs from off idle (a good tire smoker on a 650), mid and top no change. but the vibration (no rebalance) was pretty bad. might have been less if the motor was tighter, but it had a hard life. ended up getting some bearings from taffy and reinstalling it.

 

[spanner]

Anthon Berg,

I have my 05 628 apart at the moment 10000Km and the counterbalancer bearings look fine.
But I will be replacing them with two ceramic bearings I have ground down, only because I already have them.

I supect damage may be done when the main bearing fails and debris enters the balancer bearings.
I had a discussion with Ben Ballard in December 2010 and his responce was,
"The crank shaft can be run with a counter balancer or with out but we recommend that it is run with the balancer. The weak point of the Husaberg is the main bearings and the cases, a set of Husaberg cases which includes the barrel of course is lighter than a set of KTM 250 4-stroke cases! Just for reference. Having a counter balncer reduces the stress on the cases and makes the engine feel smoother"

I am quite happy with the balancer in as the bike runs plenty smooth enough, but no doubt it does add some noise.
The main thing with the Husaberg motor is to keep the oil clean. If you are getting more than the odd bit of metal
in your oil it is time to find out why, do not keep ridding it.
And IMO do not over rev it as there is not a lot to be gained by doing so.

Cheers

spanner

 

[bushmechanic]

I found it less buzzy at high rpm without the balancer and a balance factor of 75%

definitely more vibes through the footpegs up to 3000 rpm but smoother and more powerful above that

that might put some people off but i found it much nicer than a stock CR500

with the 105mm bore my balance factor changed to 0.58 and improved (reduced) vibes everywhere

62.5% is the sweet spot for the RFS apparently.

FWIW the RMZ 450s do not have a counter balancer and use a balance factor of 62%

 

[bushmechanic]

the links in the doc to these pics are not working

these are Ausbergs pics

 

[bushmechanic]

some of lineaweavers rebalanced cranks

and modified intermediate shafts (balancer drive gear ground off)

 

[bushmechanic]

there was a thread long ago discussing the possibility of a nasty harmonic set up between the balancer and the crank

since the balancer is mounted directly on the crank there has to be some form of interaction though to what magnitude im not sure I did find it a lot smoother near 7000rpm without the balancer

can't find the thread anymore, "Simon" was the main poster though lineaweaver also contributed

 

[bushmechanic]

With regard to the previous main bearing thread:

In a nutshell what I believe to be weak links:
1. Improper running clearance as a result of sloppy case bore
tolerance.

2. Axial crankshaft bore misalignment as a result of sloppy tolerance
control.

3. Using a single point, contra rotating, axial mount balance
assembly. Such an assembly induces a "Rocking Couple" which
causes the crankshaft to oscillate as opposed to rotate.


All of the above exaggerated via excessive rpm and / or loads.


Sincerely,
Dale

Simons thoughts on the harmonics are on pages 9-11 of johns main bearing thread viewtopic.php?f=5&t=6195&start=120

actually there are many posts on harmonics even up to page 22 8O

 

[bushmechanic]

there is also a good bit of info somewhere i think from Thomas of enginehardware or was it the taffymiesters ? about running a counterbalancer with only one bearing and reduced mass so as to make room for a 20mm wide bearing on the drive side

 

[tourist]

Excellent info! This all helps a lot in putting the pieces together.

 

[bushmechanic]

just to reinforce Neds point about the 82mm stroke crank being horrible without the balancer

Weed found the same thing it was horrible at all RPMs stock with no CB

but when rebalanced it was good

his initial balance factor was 90% (bit of an accident ) and he has since rebalanced again not sure how that went

 

[Taffy]

I have more trouble here with the crankshaft being undersize. if the bearings fall on the crank easily I'm afraid that it needs recoating. the bearings must be a press fit.

regards

Taffy

 

[bushmechanic]

for the CB that is fair enough

ball mains and spherical rollers on the other hand need a slip fit to work properly, I use 1/2 a thou slip between the spherical roller and the crank (not an interference fit).

DJH, GWR, Travis, Cut7 and Caflash worked out ball mains last longer with a slip fit.. collectively they have data from over 1000 RFS builds

the Nj206 STD rollers don't need a slip fit obviously as they allow axial play between the race and the rollers

 

[zaga]

Hi
I've just done that mod to one pair of NTN 6906 and they are fine, strangely I just found 6906 with C3 from NTN, no one else ??

I've also glued the bearings to the CB and to the crank, since it look to me that the old ones were slipping, hope it was a good decision.

For now, so far so good.

:cheers:
ZAGA

 

[ned37]

I've also glued the bearings to the CB and to the crank, since it look to me that the old ones were slipping

that was the reason i pulled the cb from my '02 650. the new ones were tight enough in the balancer but still an easy slip fit on the crank.