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Counterbalancer again

Joined Jul 2005
181 Posts | 0+
Högsby, Sweden
Is there any way to determine if my -02 501 has a single or double bearing counterbalancer by means of engine serial#. Only for peace of mind. 140 hrs and all is well.

Having read several dicussions on the subject of counterbalancer, I have understood that it is a point of failure and that it can be removed without much discomfort. Some have also claimed that gyroscopic effects are WORSENED with the use of a counterbalancer.
This can not be true, since it´s rotation is opposite that of the crank. I think it was added not for comfort, but as a way to lessen gyroscopic effect.
It is easy to visualize this if you just know how a force applied to a rotating wheel behaves. The force is simply translated 90 degrees in the forward direction of the rotation. So, the force applied when you tilt the revving engine results in a yawing force. The counterbalancer (rotating in the opposite direction) will always create a force opposite to this. The net result should be less gyroscopic effect. To what degree I don´t know.
Also, nothing has been said of how much power it robs. The general thinking in car-tuning communities is that you loose 5-10 hp in a 200-300 hp four cylinder engine.

I am planning on doing exactly nothing about this if it turns out I have dual bearings. If I have a single bearing, there is a good chance I fabricate a spacer and simply remove it some dark winter day as a preventive measure.
 
Hello Aspen,

Because you have a 501, it is slightly less of an issue since, as you probably already know, most of the c/b issue were encountered on the 650 engine, some on the 550. Both of these having significantly more c/b mass than the 501.

The really neat bit about the 'berg c/b is that, as you say, it is located on the crank shaft and therefore does have an influence on the gyroscopic effect of the crank shaft. I'm not sure who has said these are worsened by the use of this c/b assembly, but in my experience, there really is no "real" difference between riding with or without the c/b in place, even with a re-balanced crank. I do think however, that several people have expressed their concerns tat the removal of the c/b may have a detrimental effect on the flywheel weight, thus increasing the likelihood of stalling etc. - personally, I feel this fear is unfounded and a myth.

As for comfort, the c/b does indeed prived for benefits, again this being the design intelligence of the Husaberg engineers - a c/b that lessens gyroscopic effect AND increase comfort. You ride a berg back to back some something like a KTM LC4 or 660 supercomp or even some of the Husqies and you get the idea :wink:

The other issue with regards to the c/b is that with the right design, the direction of forces can be changed so less is perceived by the rider, rather than cancelling them out completely - obviously this will have added advantages in comfort along with others such as reducing overall load on the main bearings etc.

As for my experience testing on the dyno - and I now have well in excess of 150 tests on the 650 engine in various configurations - the advantages/disadvantages of c/b removal very dependent upon whether or not the crank has been re-balanced or not, and the balance factor used in doing so.

If you just remove the c/b without re-balancing the crank, the engine will be fine - it is a myth that you "have" to re-balance the crank because in actual fact, the resultant balance factor without the c/b is usually somewhere between 30-40% - which is pretty good as far as things go.

With the c/b removed and no re-balancing, I have not experienced any marked improvement in peak power but I have noticed improvements in acceleration - which is anticipated due to the removal of hefty items with significant rotational intertia. Riding experience show I have less traction under the same conditions compared to with c/b present.

However, this is not the case when the crank is balanced at higher factors. Dale Lineaweaver balances his cranks at a 70% balance factor and to achieve this, you need to add considerable weight to the crank - therefore, there won't be a reduction in perceived flywheel effect, nor will there necessarily be the same perceived reduction in traction during acceleration as per without re-balancing. Some of the guys over here are re-balancing to 85% with very good effect too.

As for power output, with the additional weight added, there won't be a huge effect on power output in itself but there will be benefits from the reduction of friction losses and some rotational inertia - the engine will become more efficient.

As for you orginal question, there was a mark on the side of the engine designating whether the engine has single or double bearing. It has been metioned on this site some while ago - perhaps it is in Taffy's doc. or someone else remembers - I don't.

My preference, heavily influenced by Dale Lineaweaver, is to junk the c/b, then preferrably re-balance the crank - at least then you can forget about the whole issue and just ride!

I'm sorry if this doesn't answer your question directly but gives you my experience and opinion of the whole issue.

Cheers,
Simon
 
Hi!

My -02 501 had the single bearing c/b I found out after it failed (Or rather pulverised). The bike had less than 100 h on it. So my advice would be to at least check it up if you're feeling worried, I wish I did...

Im puttin down about 6000 SKR (800 USD) to fix it and im not puttin the c/b back in, to scared of it..
Be happy to tell you how it feels in about a month or so.

Bye the way, does anyone know the size of a suitable spacer to replace the c/b? And would it be a good idea to make one of an old mainbearing?

cheers

/Erik
 
Hello Erik,

12mm would do fine for the spacer. After that, use the shims available to fine tune - they are .2mm thickness

Hope this helps,
Simon
 
i am going to refit my counterbalancer the next tim,e my engine is down. it's just not critical enough to be worth it. the bike is rougher and that robs power full stop!

regards

Taffy
 
Aspen said:
Is there any way to determine if my -02 501 has a single or double bearing counterbalancer by means of engine serial#. Only for peace of mind. 140 hrs and all is well.

Long time ago I saw a post about this. If I remember right there should be a mark on the engine if a double bearing is fitted. I will remember that R3 should be written on the engine if updated. However, my bike has double bearing without the R3 mark but the engine was rebuild by Husaberg after sold to the customer.

I have asked Husaberg about if it is possible to know if there are double bearing or not if they know the chassie number. I was very surprised when they told me that they didn't know which components they use in each vehicle.
 
Like I said before, there is a wealth of knowledge in this forum.
Thank you Simon.

mikst:

I´ve found the post you were referring to here

There is no such mark on mine, and I have also found that the previous owner was an early bird (bought it in late 2001). Now I know it´s one of the early -02´s.

taffy:

In your opinion, does the increased vibration w.o. cb really hurt driveability to such a degree? And did you re-balance or just remove?

kasta / Erik:

It would be nice to hear back from you after your rebuild w.o. cb.
I am at this point determined to replace or remove. Soon.
 
I DIDN'T REBALANCE. AND AS SUCH I HAVE TO DECIDE WHETHER TO REBALANCE or to put it back in. my point is that an unbalanced engine that vibrates ROBS you of power and in n no way can removing the balancer on it's own be said to gain power or if so, very little.

it is so lumpy without the balancer that i can't see how balancing the crank will stop me getting white-finger etc, etc.

on the basis that this is a dirt bike and that you rarely if ever use all the power; i'm putting it back in.

regards

Taffy
 
Taffy,
I totally agree with you, don´t get me wrong. Driveability is not to be sacrificed on an enduro bike without a very good reason. Seems like an upgrade to dual bearings is stable enough and the way to go.
Thanks for your input.
 

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