Does anyone know if this balanced crank is good

[Juicyjayocean]

https://www.ebay.com/itm/4034735141...-dskmaigqjm&var=&widget_ver=artemis&media=SMS I haven't seen any video with this balance pattern is it good or not

 

[ImpulseRocket]

Genericly speaking it should be slightly better, but the one place weight should have been removed was left alone. The only way to really know would be to find the balance factor with your piston of choice.

 

[Juicyjayocean]

Right that why I'm wondering I messed my crank up horribly trying to balance it's way off center and the drill bit went sideways because of the s**t drill press I have

 

[Cannonball3]

I can recommend this crank. I have one in my Athena Minarelli hybrid. Its smooth all the way to the mid 50s
Where I chicken out.
I also balanced a Zeda crank under Nick919s gracious instructions. Besides a resonance @26-29 its silky smooth above that. Both are in the same drill pattern
Drilling is critical in that all holes however deep required by the balance factor be identical as to their positions. I used a drill stop to insure this. You just cant get good results by the TLAR method.

I also wonder why no one is balancing the whole reciprocating mass. Clutch and mag rotor also.

 

[Nickt919]

I can recommend this crank. I have one in my Athena Minarelli hybrid. Its smooth all the way to the mid 50s
Where I chicken out.
I also balanced a Zeda crank under Nick919s gracious instructions. Besides a resonance @26-29 its silky smooth above that. Both are in the same drill pattern
Drilling is critical in that all holes however deep required by the balance factor be identical as to their positions. I used a drill stop to insure this. You just cant get good results by the TLAR method.

I also wonder why no one is balancing the whole reciprocating mass. Clutch and mag rotor also.

I cannot take credit for any of the balancing & true processes. I followed instructional videos as closely as possible to do mine.
When you follow StreetRyderz balance factor video instructions the drilled holes come out looking just like the Smolik crank pictured. If I remember correctly StreetRyderz video instructs to stay 50% or below on the BF and Smoliks is listed at 55%-60%.
With that in mind...you'd have to weight everything and do the calculation with that Smolik crank with what ever top end you use to see what the actual numbers are.
I have the same resonance at just about the same speed as Cannonballs. That may...or probably..is from too low of a factor. I was afraid to go over. The cost of a ruined crank is not the issue. It's all the work to find out it runs bad from going over.
I have another engine I've been wanting to try a different BF than what I have now....42%-43%.....to one a bit above 50%.

The second half of the balance process is the truing. Even if the balance holes are precise, if the crank spins out of true it wobbles. This means the magnet, crank lobes, and bevel gear are all sending out bad vibes.
If you put a dial indicator on the crank ends you'll probably be amazed how off the crankshaft ends spin/wobble. The crank lobes have to be in sync as well as the distance from one lobe to the other the same all the way around.
2StrokeStuffing has a video showing this and how to correct it. Again....I just followed others instructions.

 

[Chainlube]

I cannot take credit for any of the balancing & true processes. I followed instructional videos as closely as possible to do mine.
When you follow StreetRyderz balance factor video instructions the drilled holes come out looking just like the Smolik crank pictured. If I remember correctly StreetRyderz video instructs to stay 50% or below on the BF and Smoliks is listed at 55%-60%.
With that in mind...you'd have to weight everything and do the calculation with that Smolik crank with what ever top end you use to see what the actual numbers are.
I have the same resonance at just about the same speed as Cannonballs. That may...or probably..is from too low of a factor. I was afraid to go over. The cost of a ruined crank is not the issue. It's all the work to find out it runs bad from going over.
I have another engine I've been wanting to try a different BF than what I have now....42%-43%.....to one a bit above 50%.

The second half of the balance process is the truing. Even if the balance holes are precise, if the crank spins out of true it wobbles. This means the magnet, crank lobes, and bevel gear are all sending out bad vibes.
If you put a dial indicator on the crank ends you'll probably be amazed how off the crankshaft ends spin/wobble. The crank lobes have to be in sync as well as the distance from one lobe to the other the same all the way around.
2StrokeStuffing has a video showing this and how to correct it. Again....I just followed others instructions.

You can change the BF by filling in the holes with a lighter material than the steel you drilled out. This also reduces the turbulence inside the case and increased airflow.

 

[ImpulseRocket]

I also wonder why no one is balancing the whole reciprocating mass. Clutch and mag rotor also.

Because they have minor roles in the harmonics game. The crank, rod, and piston are the lions share of the mass being flung around, and a good bit off that is offset whilst being flung around.

The rotor is small in diameter and symmetrical in shape. The clutch is light and just spins.

You could balance them, but I doubt you would notice a whole lot.

 

[Cannonball3]

Thanks for the explanation IR!

 

[Street Ryderz]

over 50 percent bf starts to lose bottom end torque as there is not enough weight to over come the compression as well, it also reduces rpm under load, 40-50 percent is best suited to our china girls in my findings over that just lost power.

 

[ImpulseRocket]

over 50 percent bf starts to lose bottom end torque as there is not enough weight to over come the compression as well, it also reduces rpm under load, 40-50 percent is best suited to our china girls in my findings over that just lost power.

It's all about that finding the happy medium with the engine in question. The limited revs is also not entirely a bad thing. My engine still wants to scream past 9000. I don't want it to.