Counter balancer//////////weighted

[GOTFEAR]

Ok her goes my friend told me if you have a big bore like 330 350 you should add more weight on the counter balance to make up for the extra weight of the piston

[86 Quad R]

can very well be done and isnt a bad idea but care should be taken in doing so although most dont address it. if too much is added a risk of it not fitting into the engine will result.

[gsxr68]

sounds like your friend is a genius

[wilkin250r]

The theory make sense, but believe me, that is a LOT easier said than done.

Sure, the counterbalance is there to offset the movement (and weight) of the piston. One could naturally assume that with the added weight of a larger piston, you would want to offset that with additional weight on the counterbalance.

But it's not that simple.

In reality, only about half the piston weight is offset by the counterbalance, the other half is offset by additional weight on the crank. So in order to truly offset the entire additional weight of a larger piston, you would need to add weight both to the counterbalance AND the crank.

Now things get more complicated, don't they? It's not just additional weight here and there, because now the added weight on the counterbalance needs to match the added weight on the crank because they offset each other forward and backwards, and add together to offset the piston upwards and downwards. You're not dealing with one variable anymore, you're dealing with three variables that all have to match each other.

Not to mention, adding additional weight to the counterbalance and the crank is no small task in itself, let alone to balance them together.



Gets pretty complicated pretty quickly, doesn't it? That's why most people don't bother. I've only known a select few to even get close to pulling it off, and they said it just isn't worth the hassle.

[86 Quad R]

EXACTLY!!!

[C-LEIGH RACING]

Man this is old.

You ol Mac Dizzy guys, should remember Rick tryed that, adding weight to the balancer & it was more trouble than what good it did.
1st off, best I can remember, there was only one other metal material that was heavier than the iron the balancer is made of to create the extra weight & I got no idea what that was.

In the real world & if there was some way to change it over, a CR250R crank is more balanced than a TRX250R crank.
The CR's heavy bottom lobes are heavier inside the tins than the TRX crank, but, the flywheel side of the CR crank is machined different from the TRX crank. The flywheel taper on the shaft is the same, but the overall lenght of that side is shorter than a TRX.


However though, old mans talking now, YOU, could take the CR crank clutch side half & press it together with the TRX flywheel side half for just a bit better balancing action, BUT, the CR clutch side half dont have the little dot on the end to time up the balancer gear.
Thats not a big problem though if you know where the dot has to go. :D
Neil

[GOTFEAR]

Originally posted by wilkin250r
The theory make sense, but believe me, that is a LOT easier said than done.

Sure, the counterbalance is there to offset the movement (and weight) of the piston. One could naturally assume that with the added weight of a larger piston, you would want to offset that with additional weight on the counterbalance.

But it's not that simple.

In reality, only about half the piston weight is offset by the counterbalance, the other half is offset by additional weight on the crank. So in order to truly offset the entire additional weight of a larger piston, you would need to add weight both to the counterbalance AND the crank.

Now things get more complicated, don't they? It's not just additional weight here and there, because now the added weight on the counterbalance needs to match the added weight on the crank because they offset each other forward and backwards, and add together to offset the piston upwards and downwards. You're not dealing with one variable anymore, you're dealing with three variables that all have to match each other.

Not to mention, adding additional weight to the counterbalance and the crank is no small task in itself, let alone to balance them together.



Gets pretty complicated pretty quickly, doesn't it? That's why most people don't bother. I've only known a select few to even get close to pulling it off, and they said it just isn't worth the hassle. well heck i thought i would just add a wheel weight on it a once or two weeeee

[GOTFEAR]

what is that thing they do for the cr500 balancing the crank , rod and piston why not the 250r

[wilkin250r]

Originally posted by C-LEIGH RACING
Man this is old.

Every once in a while, some young kid comes up with a idea he thinks that nobody has ever thought of before. It's our job as the older generation to dash those dreams to bits. :devil:


Actually, the balancing would be very do-able if you could trench the cases to allow you to weld weight to the outside of the counterbalance, and also do the same with the crank. A special fixture to hold and spin the entire assembly, and it becomes only slightly more complicated than balancing a tire, I could design a complete system for about $500k