Running with no balance shaft

Post by **Eddie Evans** » 28 Jul 2010, 12:28

Just to pass on some info.
I've been running my bike now for a few hard rides with the balance shaft locked up. I replaced the drive gear with the inner race of a wheel bearing. The shaft is still there but does not turn but does seal the oil way..

Results of the seat of the pants dyno are that the bike feel snappier especially when the throttle is whacked open.
Vibration is bad when the bike is cold and first started but smooths out a bit as it warms up. Off road the vibes are not noticeable. On the road for long periods and I suspect that the vibs through the handlebars will be the main concern. White finger anyone

I had thought this mod would cause the bike to stall easier but I have not noticed that.

So if you balance shaft is on the way out or you are looking for some more off road performance this could be worth a try. If your clutch gasket is intact it cost nothing apart from an hours time and work.

superbob · Post by **superbob** » 28 Jul 2010, 22:56

Im getting a knocking noise from the bottom of my engine I checked the crank when I had the barrel re bored so I think the balance shaft bearing has gone is it a big job to change it or do I have to split the casings.

Post by **Eddie Evans** » 29 Jul 2010, 01:26

The noise from a worn balance shaft is more of a high pitched whirring noise than a knocking noise that goes up and down in volume as revs rise and fall.
It is not a big job to change it.
viewtopic.php?f=20&t=5536
Do a search and you will see drawings for a tool to knock out the needle roller

If you have any questions after looking at the link please ask.

Post by **knackeredMk1** » 02 Aug 2010, 08:53

Interesting. I always wondered what would be the extent of the effect of grinding off the steel plate that is on the end of the generator rotor. I am assuming it would lead to quicker pickup without the extra vibes

. I've not known anyone do it.

Paul P · Post by **Paul P** » 02 Aug 2010, 10:27

I would say your a brave man. The part your are talking has a key word in it's description (balance)

and now that you have played with it you are experiencing bad vibration in the handlebars which is been

generated by your motor, I would listen to what your motor is telling you.

Post by **knackeredMk1** » 02 Aug 2010, 10:37

Removing the balance shaft is quite a common modification - All hardcore racers in Japan do it. At worst the bike will vibrate like an MX bike and the symptoms are mostly noticable on the road as has been stated.

Paul P · Post by **Paul P** » 02 Aug 2010, 11:27

Each to there own It's not a modification i will be making

Post by **Eddie Evans** » 02 Aug 2010, 16:39

Paul P wrote:I would say your a brave man. The part your are talking has a key word in it's description (balance)

and now that you have played with it you are experiencing bad vibration in the handlebars which is been

generated by your motor, I would listen to what your motor is telling you.

Thanks for your input

Running with no balance shaft

Running with no balance shaft

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