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Crankshaft balancing

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This winter im thinking of tearing down my 17 300 to get the crankshaft rebalanced/aligned instead of spending money on anti vibration foot pegs and bar clamps etc.

 

has anyone ever get that done? If so were is the best shop for that?My bike is vibrating quite a bit and from what my dealer tol me is that its hit and miss. Some are good some are bad.

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Are you planning on doing this because you believe the crank is out of balance, and you want to remove some vibrations?

Guess what: it is, on purpose.....

 

Without a counter balancer, you cannot balance the crank without adding a large amount of weight to it....which the rest of the motor is not designed for.

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6 hours ago, THE KRAN said:

Are you planning on doing this because you believe the crank is out of balance, and you want to remove some vibrations?

Guess what: it is, on purpose.....

 

Without a counter balancer, you cannot balance the crank without adding a large amount of weight to it....which the rest of the motor is not designed for.

So basically what your telling me is that id be wasting my time sending to get rebalanced?

Ive owned several 2 strokes before and this one is excessive. My hands and feet get really numb. Obviously i retorqued every bit of hardware on it and i run a lectron and its tuned perfectly.

 

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2 hours ago, Derik Violette said:

So basically what your telling me is that id be wasting my time sending to get rebalanced?

Ive owned several 2 strokes before and this one is excessive. My hands and feet get really numb. Obviously i retorqued every bit of hardware on it and i run a lectron and its tuned perfectly.

 

If you are pulling the crank anyway, sure it can't hurt to have it speced, but all they can add is grams to make in balanced to the rod and piston. They cannot practically balance it for reduced vibration, only to move the vibration to a different frequency. You can achieve the same thing by being creative with all of the motor mount's torque specs. 

The experts say:

Single cylinder motors have a rod and piston jumping up and down causing strong vibrations. 
Without a counterbalance shaft in the motor you cannot eliminate the vibration. you can only moved it to an rpm range that doesn't bother you as much. 
The manufacture accomplish this by changing the balance factor (heavy area on crank opposite of rod journal can be any where from 60 to 70% of weight of piston and half of rod.) 

 

 

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There can and will be differences in production crank alignment.  Its the precision of the alignment not the balance, no material is added or subtracted in this service.  Changing the balance factor yes, but likely not necessary especially since you are familiar with 2strokes.  The crank is a precision part so it would be unlikely the mass varies in production.  I have a Beta that is exceptionally smooth yet others I have ridden are not.  Pre '17 KTMs were the worst.  What you can do ASAP is loosen all the engine mounts and re-torque, starting with the swingarm pivot and ending with the head stay.  If it vibrates abnormally there is a reason and I'd fix it as well.

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4 hours ago, GP said:

There can and will be differences in production crank alignment.  Its the precision of the alignment not the balance, no material is added or subtracted in this service.  Changing the balance factor yes, but likely not necessary especially since you are familiar with 2strokes.  The crank is a precision part so it would be unlikely the mass varies in production.  I have a Beta that is exceptionally smooth yet others I have ridden are not.  Pre '17 KTMs were the worst.  What you can do ASAP is loosen all the engine mounts and re-torque, starting with the swingarm pivot and ending with the head stay.  If it vibrates abnormally there is a reason and I'd fix it as well.

Both crank alignment and how precisely it was balanced from the factory can make a difference. Production tolerances aren't as close as what a custom balance/crank shop can achieve. If it's still pretty bad after going through the motor mounts etc and you're willing to strip the motor it can make a difference, but it's hard to predict how much.

As mentioned, adjusting the balance factor can be effective also but will mostly move the range up/down but that can be useful to get things in your preferred riding rpm range to be as smooth as possible. I've had some engines balanced and it can be effective at improving things, but it depends on how bad it is to start with. A lot of guys found the balance factor on older Brit twins was 50% from the factory and it really improved things overall to go to a 70% factor.

My KTM 300 vibed pretty bad. I haven't ridden any Beta 300s but most larger bore 2-strokes I've ridden vibrate a good bit. It's one reason I moved on to 4-stroke cuz they had counter balancers and I wasn't getting as fatigued. 4-strokes w/o counter balancers were just as bad. I love 2-strokes and am super happy to see KTM finally counter balancing their 300 and hopefully Beta and others will follow suit as IMO it's warranted. Ya it adds a bit of weight, but in my opinion it's weight very well spent as it both reduces fatigue and the effects of vibration on the rest of the bike which are both good things.

 

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18 hours ago, danketchpel said:

Both crank alignment and how precisely it was balanced from the factory can make a difference. Production tolerances aren't as close as what a custom balance/crank shop can achieve. If it's still pretty bad after going through the motor mounts etc and you're willing to strip the motor it can make a difference, but it's hard to predict how much.

As mentioned, adjusting the balance factor can be effective also but will mostly move the range up/down but that can be useful to get things in your preferred riding rpm range to be as smooth as possible. I've had some engines balanced and it can be effective at improving things, but it depends on how bad it is to start with. A lot of guys found the balance factor on older Brit twins was 50% from the factory and it really improved things overall to go to a 70% factor.

My KTM 300 vibed pretty bad. I haven't ridden any Beta 300s but most larger bore 2-strokes I've ridden vibrate a good bit. It's one reason I moved on to 4-stroke cuz they had counter balancers and I wasn't getting as fatigued. 4-strokes w/o counter balancers were just as bad. I love 2-strokes and am super happy to see KTM finally counter balancing their 300 and hopefully Beta and others will follow suit as IMO it's warranted. Ya it adds a bit of weight, but in my opinion it's weight very well spent as it both reduces fatigue and the effects of vibration on the rest of the bike which are both good things.

 

They definatly need to add a counter weight balancer. I tried my buddies 2017 husky and it has no vibration at all. 

When i do a top end next year, i will  send it out just to get checked and aligned. Till then Will try some anti vibe foot pegs and bar clamps.

 

thanks alot guys for taking the time to explain all this to me

 

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