Balancer shaft question

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dandan0162
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Balancer shaft question

Post by dandan0162 » Mon Jun 26, 2017 10:18 am

Morning all, I have rebuilt my motor, crank has been rebuilt with new seals n center shaft,new top end,all bearings checked and replaced where needed so I started the bike and then realised something is drastically wrong,the engine wanted to shake it's self out the frame strong vibrations on tick over ok,

I have checked the balance shaft both dots was aligned
Checked ignition timing and pick up to spec was ok
Checked with strobe and was firing correct although strobe was not a constant patarn was picking up an odd misfire it seemed?
Bike start firt kick same temp both sides,
I have a feeling that the balance shaft gear is 180° out
Is this possible when rebuilding a crank?

Does anybody know where both pistons are supposed to be when the balance shaft is correctly lined up?

I was going to turn 180 to the correct point and see if that cures it.

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JanBros
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Re: Balancer shaft question

Post by JanBros » Mon Jun 26, 2017 3:02 pm

sure the balancer is aligned correctly ? 1 time putted it one tooth wrong and it did exactly what you describe.

false alignment of balancer sprocket is also possible. will check this evening on a spare crank where it needs to be.
You know it's cold outside when you trip over dog shit instead of standing in it.

dandan0162
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Re: Balancer shaft question

Post by dandan0162 » Mon Jun 26, 2017 3:40 pm

Hi jan thanks for the reply yes im sure it's correct both dots line up on each gear,I'm thinking the balance gear on crank has been put on wrong if you can check that would be helpfull,thanks dan

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Re: Balancer shaft question

Post by JanBros » Tue Jun 27, 2017 10:23 pm

Image

crank is standing on the primary gear, dots probably are right in the middle of the stroke
You know it's cold outside when you trip over dog shit instead of standing in it.

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Re: Balancer shaft question

Post by JanBros » Thu Jun 29, 2017 7:12 pm

so, how did it compare to yours ?
You know it's cold outside when you trip over dog shit instead of standing in it.

dandan0162
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Re: Balancer shaft question

Post by dandan0162 » Mon Jul 03, 2017 11:03 am

Looks to be out for sure jan,this is going to be a pain😯so in the middle of stoke so pistons are in line with each other do u think it could take a few tries mind you.

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JanBros
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Re: Balancer shaft question

Post by JanBros » Mon Jul 03, 2017 6:12 pm

who split/rebuilded the crank ?

a jig should have been made. if you have another crank, that can be used to make one and then reassemble this one using the jig.
1 tooth wrong made my engine unrideable, so even 1/4th wrong will be too much in my opinion.
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dandan0162
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Re: Balancer shaft question

Post by dandan0162 » Wed Jul 05, 2017 10:38 am

It was fahron he built without a the use of a jig jan,I have no doubt the crank is true ect but this seems to have sliped his mind as you said the gear could be off by half or 1/4 of a tooth...so it's not force to time up correctly ever ,what a pain in the arse this is
I don't have a spare crank but I could ask stan or sep for there thoughts n if they can put right.

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Re: Balancer shaft question

Post by podman » Wed Jul 05, 2017 3:18 pm

dandan0162 wrote:
Wed Jul 05, 2017 10:38 am
It was fahron he built without a the use of a jig jan,I have no doubt the crank is true ect but this seems to have sliped his mind as you said the gear could be off by half or 1/4 of a tooth...so it's not force to time up correctly ever ,what a pain in the arse this is
I don't have a spare crank but I could ask stan or sep for there thoughts n if they can put right.
Why cant you go back to Fahron?....

dandan0162
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Re: Balancer shaft question

Post by dandan0162 » Wed Jul 05, 2017 9:54 pm

If bin to see ron and he as put the shaft where he thinks right...so that when left side is at tdc the dots on the balllancer are in middle of crank gear and the counter weights are in opposite direction to pistons it looks right but I will see tomorrow just need to fit exhausts then try if not it's up for sale lol

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