Harley engine balancing, reverse engineering, and balancing

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john HD
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Re: Harley engine balancing, reverse engineering, and balanc

#31

Post by john HD »

ok let's try this again.

john
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Re: Harley engine balancing, reverse engineering, and balanc

#32

Post by saddlebagrail »

Hi to everyone reading this thread

From my first post ,about the Harley engine balancing theory ,my goal was to demonstrate to internet users and forum members here,how I do my own Harley balancing,I did experiment quite all of my life with a lot of stuff,and I will continue as long as I can,you can check my blog on Caimag,I had written a few stories, but again not all will agree on how I do my things.

http://www.caimag.com/wordpress/categor ... tech-blog/" onclick="window.open(this.href);return false;

I did try the balancing without equalizing rods and also with equalizing the reciprocating weight of rods,there is definitly a difference,but maybe it is just me that feel the difference,under the pants.....,It seem that Cotten from this forum did is own balancing but not the way I did it,and says that you could not achieve a smoother engine by equalizing the top portion of the rods(reciprocating weight) ,every engine builders that make high performance engine ,normally equalize both rotating and reciprocating weigh on all rods to achieve the best results , hopefully Cotten will demonstrate how he do is own stuff sometimes in the future...

It is very easy to criticize others work,taking example from others place from the net,ect,.....for those who want to read this thread ,hope it will help you understand the principle of the Harley engine balancing myth and help you understand how thing is done to achieve a really smooth engine,some will disagree with me and some will approve my way of doing thing ,in this case balance a Harley engine,just my 2 cents,Ray

I will not take the time to create long thread like this here anymore,don't worth the time, versus the end results.....
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Re: Harley engine balancing, reverse engineering, and balanc

#33

Post by Cotten »

Don't let your indignation get in your own way, Ray!

I use the traditional theory.
I did not invent it (I'm not that old!), but it did make these phenomenal machines the icons we revere for a Century.

You believe that you are "equalizing" the rod tops, when you actually are making them grossly unequal.

Please re-read my previous posts carefully.
Someday you will come to an epiphany. An apology to me will not be necessary.

Sincerely,...
....Cotten

PS: And no, I do not go to caimag. The owner burned me three times, and I don't even want to give him a cookie.
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Re: Harley engine balancing, reverse engineering, and balanc

#34

Post by Flathead80 »

If one lightens the small end of the forked rod, the center of mass of the rod moves closer to the crank pin. Tell me, Cotten, does this not reduce the reciprocating mass of the forked rod? What Ray is doing is reducing the reciprocating mass, which is a desirable thing. It also brings the reciprocating weight of the forked rod closer to the reciprocating mass of the male rod. Quite frankly, Ray's method is better than yours, as it places the system into a better state of balance. I realize now that you will never admit it, but as you succinctly pointed out, what you say and how you say it says more about one than one suspects.

Have a nice day, Cotton. If I had known your only complaint was that you just didn't like the idea of altering the rod end from the mistaken idea that it placed the system at a greater level of imbalance or damaged the rod, I would probably have just watched another episode of Lassie.

Jim 8)
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Re: Harley engine balancing, reverse engineering, and balanc

#35

Post by Cotten »

Jim!

Please think seriously about it.

You want the masses of the two rod tops that are moving in different directions to be equal.
Intuition, if not common sense, should tell you that they should be of similar size.

The rotating mass of the unequal bottoms move in unison, because there is only one "throw", or crankpin, unlike an auto.

The whole point of hanging rods to weigh them is to account for the proportional reciprocating mass of the bottoms.
That is why female rod tops will always calculate to weigh more than male rod tops.

But there is only one reciprocating mass for a V-twin: All of it.

Please think seriously.

This point of view is not my own, but belongs to the V-twin motor designers' of the entire last century.
You argue with the Founders, not me.

....Cotten
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Re: Harley engine balancing, reverse engineering, and balanc

#36

Post by Flathead80 »

Are you trying to tell me that moving the rod center of mass closer to the crank pin does not reduce reciprocating mass?

Jim
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Re: Harley engine balancing, reverse engineering, and balanc

#37

Post by Cotten »

Our disagreement, Jim,..

Is the whittling on the female rod top.

It does not make the masses moving in different directions equal, it makes them unequal.

Fortunately for you, the design is so forgiving, that the motors will run "smoothly" even with different sizes of pistons!

....Cotten
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Re: Harley engine balancing, reverse engineering, and balanc

#38

Post by saddlebagrail »

Hi Cotten

To try to clear something here.....Concerning the female rod reciprocating weight,it is not always the case that the female top rod(female reciprocating part) is heavier than the male top rod,I would say 50 /50,sometimes male reciprocating is heavier than the female and sometimes female is heavier than male reciprocating weight,so about half and half,anyway from the last few balancing jobs I did ,but maybe those thing just happen to me:-),but I could tell that they are about the same in average,I just made a check in my previous balancing sheets.


....now about pistons,even if they are different size it really doesn't bother too much if you are using same brand /type,the reason is they are very close to each other in weight, from standard size to maximum oversize,let say at .070 in over,all that for the purpose to stay close as balancing as the flywheel were balance before,so you do not have to take the bottom end out to balance again due to a change in pistons,you could check several size of pistons from the same manufacturer and you will see that there are very close to each others,Ray
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Re: Harley engine balancing, reverse engineering, and balanc

#39

Post by Cotten »

Ray!

Of the dozens of Harley and Indian rods that I have weighed over the last three decades, the female rod top was invariably, significantly heavier than the male.

It is half of a much heavier rod!

And my point about running "smooth" even with different size pistons is that what the rider feels has nothing to do with the balance.
If you've got shakes, you've got a mechanical problem.

....Cotten
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Re: Harley engine balancing, reverse engineering, and balanc

#40

Post by saddlebagrail »

Hi to all

Well I don't know what to say, to prove that sometimes male top rod portion(part of reciprocating weight) is heavier than female top portion of rods,the best I can do to prove my point is show some of my balancing sheets,so all can see what we are talking about,for sure complete female rod is heavier nothing to argue here ,this is not the arguing is about right now, but the top reciprocating portion that we have a different perception of...

here is my sheets,all name date address and serial number have been covered for simple reason but the rest is all there,it is kinda open to public which is not something I do very often,but if it can help clarify some thing ,maybe it would help some understand that it is not necassary the top female rod portion that heavier all the time but it happen that top male portion could also be heavier sometimes.

Cotten specify that over décades of weighting different rods.......the female rod top was invariably, significantly heavier than the male.


As you can all see I use my own custom made balancing sheets.You could see in the third pics that this set up use S&S rod(Supreme) which was amongst the biggest difference I have seen,for the rest they are close so not too much to take off the top of rods,piston or even wrist pins...note also the big end(rotating part of rods you could see that female is way heavier but not necessarly the top portion) some use different factor than me,but I am quite satisfied with the 60% factor,58% for racing seem to be better by some, as some still use the 50% factor that Harley was using until 1973 ,and some use the 55% factor,it will just move the compromise to another range of rpm/speed,but this is not the arguying right now but more about top female portion that is much heavier all the time which is NOT true,...or maybe those things just happen to me over time,Ray

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Re: Harley engine balancing, reverse engineering, and balanc

#41

Post by Flathead80 »

Cotten wrote:....And my point about running "smooth" even with different size pistons is that what the rider feels has nothing to do with the balance.
If you've got shakes, you've got a mechanical problem. ....Cotten
You are just plain old wrong on this one, Cotten. A Harley engine can be so far out of mechanical balance that it will shake you 'til you just want to go home. Check out Balance Masters. They make a living reducing bike shake, and they do it by balancing the engine. I have improved the ride of old flatties, and some drastically, simply by balancing the engine with no other modifications to the bike.

http://www.balancemasters.com/hotbikespread.html" onclick="window.open(this.href);return false;

I am amazed you would make such a statement.

Jim
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Re: Harley engine balancing, reverse engineering, and balanc

#42

Post by Cotten »

I have my own sheets too, Ray!

Looking over a handfull that I did not give back to the customers who paid for them, I see the least difference of 6g for S&S rods, and the most was 27g, with a median of somewhere around 15g.

Even a sheet from a 1976 job I farmed to Lakeshore is 22g difference.

When weighed to the tenth of a gram, I consider 3g significant.

Half of a big rod will always be more than half of smaller rod.

I cannot view the first page of this thread, as my dial-up freezes after a megabyte per page, and I get an "illegal operation" window.

So I suspect your means of "hanging" the rods.

Did you keep it simple?
Note bubble-level to "zero" scale before weighing.
Note bubble-level to "zero" scale before weighing.
RODHANG.jpg (42.42 KiB) Viewed 3795 times
....Cotten
PS: Jim!

Stop listening to your barroom buddies.

Balancemasters does not balance, it dampens.
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Re: Harley engine balancing, reverse engineering, and balanc

#43

Post by Flathead80 »

Cotten wrote:Our disagreement, Jim,..Is the whittling on the female rod top. It does not make the masses moving in different directions equal, it makes them unequal. Fortunately for you, the design is so forgiving, that the motors will run "smoothly" even with different sizes of pistons! ....Cotten
The masses of the rod were already unequal, but matching the small end rod weights improves the balance and reduces reciprocating weight. It is a matter of physics; and unless you can demonstrate mathematically that I am wrong, you won't change my mind.

Jim 8)
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Re: Harley engine balancing, reverse engineering, and balanc

#44

Post by Cotten »

C'mon, Jim!

Reducing your reciprocating weight only increases your factor.

Folks,

Back in the '80s, 52% was the preferred factor,

Then over time, 60% became the preferred factor.

They all ran "smooth".

How can that be?

Its because shakes are a mechanical issue.
Any decent overhaul should correct shakes.

Balancing a V-twin is a tuning tool.

....Cotten
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Re: Harley engine balancing, reverse engineering, and balanc

#45

Post by Mr.Big »

I'll bet this all winds up as one of those '' agree to disagree '' threads but I have enjoyed the discussion immensely...

PS, Tom, we only collect chocolate chip cookies at caimag........ :) o
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