Lightening Counter balencer

[Honda 250r 001]

Has anyone ever had their counter balencer lightened thats not drag racing? I was looking to get this done by dave moor racing. http://www.davemooreracing.com/Counter_Balencer.html for quick revs and fast acceleration out of the corners. Yay? Nay?

[speedfreek]

I've had mine lightened. It's been a few years ago. Seems to be holding up well. I think every little bit helps.

[Pumashine]

Originally posted by Honda 250r 001
Has anyone ever had their counter balencer lightened thats not drag racing? I was looking to get this done by dave moor racing. for quick revs and fast acceleration out of the corners. Yay? Nay?

I use them on the smaller motors. Rev's quicker but almost not noticable. You cannot use these on motors bigger than 350cc. Its only an extra $30. I have 2 of the last 3 I had rebuilt by Dave that have not been used if you want to buy or trade one. Or if you just want to try it I have one I took out to put the Puma on.

http://i53.tinypic.com/504kr6.jpg

[Honda 250r 001]

Originally posted by Pumashine
I use them on the smaller motors. Rev's quicker but almost not noticable. You cannot use these on motors bigger than 350cc. Its only an extra $30. I have 2 of the last 3 I had rebuilt by Dave that have not been used if you want to buy or trade one. Or if you just want to try it I have one I took out to put the Puma on.

http://i53.tinypic.com/504kr6.jpg

Ive got a 310 so i belive it would work. Yea I would love to have one! How much do you want for one of these lightened counterbalencers?

[Pumashine]

Originally posted by Honda 250r 001
Ive got a 310 so i belive it would work. Yea I would love to have one! How much do you want for one of these lightened counterbalencers?

I would trade straight across if your CB is in good shape.

[Honda 250r 001]

Originally posted by Pumashine
I would trade straight across if your CB is in good shape.

Sounds good! Ive got a counterbalencer with a brand new bearing that ill trade ya.

[Pumashine]

Originally posted by Honda 250r 001
Sounds good! Ive got a counterbalencer with a brand new bearing that ill trade ya.

Great, this one was used for one season. I don't know if you research lightened CB's but there is an art to it. The way these are cut not just put in a lathe and swipe off the weight. You see the angle Dave cuts into the weighted area. They really need to be done that way. I can't explain it but thats the way its supposed to be done.

Next is the amount of weight taken off. Too much weight taken off and it will vibrate the hell out of your frame. Broken motor mounts and what not. Not enough weight taken off and it won't make any difference. I believe Dave did a trial and error on these about 15 years ago when he was building the fastest R's in the northwest. Just wanted to give a little history.

Maybee someone else will chime in with lightened CB expierience and add to what I have seen happen with this topic.

I would not run a lightened counter balancer (CB) on anything above a 250R, it makes no difference on larger displacement of +250CC and actually if you are running higher compression than stock (165-180lbs), like +190lbs it is detrimental to top end performance even a 250CC engine...

why?

The “harmonic counter balancer” was designed for a specific piston weight and RPM range and more specifically it was designed for a given force. Force being the direct result of rotating upper end weight and the pressure exerted on the piston.

The harmonic CB is there to counteract the second order harmonics coming from the piston & crank. The engine has an inherent first order of balance because of the opposing motion of the piston & crankshaft. Since the piston motion is not perfectly sinusoidal, the difference in piston accelerations to crankshaft creates a second order of vibration at twice the crankshaft speed. The balancer is designed to oppose this at specific weight, RPM and force.

As displacement and compression go up, the force increases to the square of the weight & compression. On larger displacement engines, it is beneficial to add weight to the “harmonic counter balancer” as well as the crankshaft, not reduce weight.

The removal or addition of weight to the CB or crankshaft is derived from very a tricky dynamic formula, one best left to engine designers; those individuals degreed in Dynamic Enginering, not Dremel tools.

This is offered as my knowledge & opinion only.

:(

[Pumashine]

Originally posted by acecarlos
I would not run a lightened counter balancer (CB) on anything above a 250R

Carlos, you forgot to state that Honda overbuilds thier motors by 100%. Leaving much room for discrepancy. Its like a Cadilac to a VW.

The stock tranny that see's 35 horsepower can handle 70. The stock counterbalancer can handle a solid piston without any weight removed. Imagine the piston as one big hunk of aluminum without any portion removed for the rod and wristpin. That is the amount of steel that is put on the counterbalacer to do just that, counterbalance. Engineering built into these things are way above anyones expectations.

Removing wieght from the CB is not going to hurt a darn thing until the whole moving system is not balanced anymore. Don't start making up stuff that does not exist on this one Carlos!

Next your gonna say that polishing a cylinder does not allow the surface of the cylinder to disperse heat the way Honda had designed. LOL! Its just common knowledge and it does not hurt anything until you state otherwise. JMO and .02

“Don't start making up stuff that does not exist on this one Carlos!”

I offer a valid opinion and sound logic and you come back with this response?

Not trying to start anything, however; examine your statements…just because an engine can handle 2x’s the designed load, does not mean all the components are operating at the optimal design stage.

If a crankshaft or harmonic counter balancer has a given amount of weight to counter all the forces, does it not make sense that when displacement and force are increased, so should the counter weights?

Why is weight added to crankshafts when larger size pistons are used? Again; the problem here is OUR lack of knowledge, we assume everything is fine as long as an engine runs and does not self destruct…it is not!

We shoot from the hip, not examing why engines are designed how they are, yes; they are overbuilt and NO you can not simply keep changing rotating mass and force and call it all good.
What part of “my opinion” is not clear?

I admire your builds Pumashine, you do a great job...you are the big bore man! I respect that 100%, however; I know a few things relating to engine designs and dynamics, engineering and medicine…any one of these you care to discuss, I am more than willing as long it is based on solid engineering and respect.

[mxduner]

I will post what i read off of mac dizzys site about this topic it reads

After spending a considerable amount of time machining it (cast iron) I found the benefit of the lightened balance shaft to be barely noticeable and the vibration a real problem. It will let the engine rev a little quicker, but there's a phenomenon that occurs when under hard acceleration or just quickly revving the engine. The quad literally squats a couple of inches closer to the ground when revved! When racing or riding for short distances I don't think it is much of a problem but when I ran my TRX with the lightened counter balancer for a long ride the vibration numbed my hands and arms past my elbows.

i personally have no experience with this mod, but this is what i read on that site. i guess take it for what it's worth.

[Pumashine]

I admire your builds Pumashine, you do a great job...you are the big bore man! I respect that 100%, however; I know a few things relating to engine designs and dynamics, engineering and medicine…any one of these you care to discuss, I am more than willing as long it is based on solid engineering and respect. [/B]

There are alot of us who build on the edge. Some times it works sometimes it does not. Reguardless of what should or should not happen we rely on expierience.

I am not saying your insights are wrong. They just do not take all factors into account. Your decisions are based on what you know. But remeber you may not know everything. I don't give a chiat about motor building insights. I don't care about what people want to or do not want to believe.

But if you tell me a DMR lightened CB is going to be detrimental to my motor you have no real proof. Have been running a few for 10 years now and cannot see any of your claims as a reality.

On the other hand like I said there is an art to this lightening
option. Once you go to far all the bad things you say may happen will happen.

MacDizzy is absolutely right when saying it left his hands and feet numb from the ride. I witnesss this first hand when riding with the first lightened CB I bought on a drag motor. Was like a foot and hand massage at the same time. DMR's CB lightening has already taken this into account. You will not see the bike dip down when the throttle is revved. It will not make the bike vibrate whatsoever. MacDizzy did not take the time to go back and build it correctly.

“DMR lightened CB is going to be detrimental to my motor you have no real proof”…true.

I have no real proof, then again; you must admit you have no real proof that what I am saying is incorrect either.

The true test would be to try to properly balance the crank and CB to the new rotational mass & forces developed by the larger displacement. Have you tried adding weight to the CB, testing for increased or decreased vibrations, looking at the acceleration curve, and top HP with either a lightened and weighted CB on a larger displacement engine?

What if I was to show you on a dyno, that adding the proper amount of weight to the CB combined with added weight to the crankshaft when increasing displacement not only decreases vibrations, it also increases acceleration and HP, then would you listen?

I like the dialog, don’t have all the answers, however; I know the ultimate function of any mechanical unit such as an engine, changes dramatically for better or worse when a slight change is made to any of its components.

Blind tests, placebo drugs and the effects of false perception weigh heavily on what we think, feel and see, when in reality they could be only positive psychological effects…unless we can accurately document improvements, without emotion; we don’t really know if they offer a value or not…

Mxduner: thank you for sharing; I was not aware...

[mxduner]

Originally posted by acecarlos
“
Mxduner: thank you for sharing; I was not aware... hey no sweat, just trying to get any info to add to the mix. here is the link with a small pic of the cb
http://www.macdizzy.com/images/balance_duo2.gif

and the link to the page

link (http://www.macdizzy.com/trxs2.htm)

[2-330s]

i will agree with both sides on this.(but to both extremes) put a cr 500 in a trx frame most will tell you it shakes the he!! out of you but don't see the chassis drop when you stab the throttle.on the other hand put a big bore on a trx motor and they do well with a stock balancer.i have tried light and heavy flywheels (as light 5 oz or on the other hand plus 13 oz over stock),as well as light counter balancers. it's up to you what you expect as far as power delivery and reliability. do you want a snappy motor,drag motor or a long smooth pulling motor? ignition,pipe,port,reeds,head,carb,stroke,bore and compression all will or won't make it work???

All great input; thanks!

[derby]

Originally posted by acecarlos
All great input; thanks!

I like pumashine have used the lightened CB's from dave for years. And have never had any problems. The only motor I noticed vibration on was a 370. Like others have said it may not make any difference at all.

As for the mcdizzy site he cut the counter weights off completely I can see a problem with that. There is a difference between what mcdizzy did and what dave does.

[Honda 250r 001]

Has anyone else used a dave moore racing lightened counterbalencer?

I have had two since late 90’s, tried them and currently do not use them, therefore; I cannot give an honest opinion on how well they work or don’t, having seen no difference either way…

I have asked BDT Motorsports to take my 330R next week (scheduled custom TEST piston change) and run on the engine dyno the current weighted CB that BDTM built verses the lightened CB from DMR…

I promise to post the dyno sheets in 2-3 weeks; these will include vibration analysis over multi-axis measurements (90 degree apart) over the complete power band of the engine…

This study will help understand and hopefully quantify the effects of a stock CB verses a lightened CB verses a weighted CB (weight added based on displacement/force increases) in a 330R…

I like science; it helps wade through all the miss information spewed…