Engine noise

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bob64bob
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Engine noise

Post by bob64bob » Sat Sep 03, 2016 2:15 pm

I have have just rebuilt my motor and have a rumbling noise which I'm pretty sure is coming from the the crank gear and balance shaft gear , the crank has been reconditioned and I have bought another set of crankcases because mine were damaged the only part which hasn't been touched is the balance shaft , has anyone has any issues with noise or alignment between the the crank and balance shaft ?

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JanBros
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Re: Engine noise

Post by JanBros » Sat Sep 03, 2016 9:45 pm

only noise or also vibrations ? if the second -> balancer and crank not correctly lined up.
you can take out the balancer without taking the engine out, just put it straight up on it's rear wheel (did it once because of misaligning :oops: )

sure it's not the clutch ? it can rattle a lot en neutral and goes away when pulling the clutch lever
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bob64bob
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Re: Engine noise

Post by bob64bob » Sat Sep 03, 2016 11:21 pm

It's definety lined up as in the dots are aligned , when I turned the crank by hand it made a a slight noise at a particular point of the revolution after looking closer it seemed to have slight play between the cogs which I would assume is normal but at one point the play between the two cogs wasn't there, it seemed like one tooth from one of the cogs was interfering with the other, the only thing I can think of doing is trying to get hold of another balance shaft and see if that cures it

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bozbridge
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Re: Engine noise

Post by bozbridge » Sun Sep 04, 2016 3:29 pm

I had the same while I was rebuilding one of my motors, slight graunch noise turning the crank by hand and no clearance on the balancer gear at the same spot the noise occured.

I had 2 balance shafts to hand so tried them both and it didn't change so decided it mush be the crank drive gear causing the tight spot and I'd just had the crank rebuilt. In the end I put it all together and rode it for several hundred miles. When I next stripped it over last winter the tight spot had gone. Maybe the heat and expansion of running helped everything settle.

Have to make your own mind up over how bad the problem is and wether you want to do the same, but hope that might help you decide.

bob64bob
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Re: Engine noise

Post by bob64bob » Sun Sep 04, 2016 4:35 pm

bozbridge wrote:I had the same while I was rebuilding one of my motors, slight graunch noise turning the crank by hand and no clearance on the balancer gear at the same spot the noise occured.

I had 2 balance shafts to hand so tried them both and it didn't change so decided it mush be the crank drive gear causing the tight spot and I'd just had the crank rebuilt. In the end I put it all together and rode it for several hundred miles. When I next stripped it over last winter the tight spot had gone. Maybe the heat and expansion of running helped everything settle.

Have to make your own mind up over how bad the problem is and wether you want to do the same, but hope that might help you decide.
It's not terrible it just annoys me that it's not perfect, The more I listen to it the more I'm beginning to think I will run with it , the bike runs and sounds well and I think the problem is I know the tight spot is there , I was going to try another balacne shaft but I'm not totally convince it will cure it

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scooble
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Re: Engine noise

Post by scooble » Sun Sep 04, 2016 5:05 pm

if you suspend the balancer shaft in the bearings, you can probably check the runout as you turn it

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