Flywheel assy, Balancing.

[partshunt]

Hi All:- Looking for info on "how to" check and correct the flywheel rotating assembly complete to the piston rings. I checked back several pages in the panhead site, nothing found but am sure this topic has come up before. Problem is, will anyone offer the "how to do it" information? Possibly there may be something on the web?...thanks...partshunt

[Jack_Hester]

http://virtualindian.org/Flywheeltheory.htm

http://victorylibrary.com/tech/inertia.htm

http://www.terra-glide.net/harley_tech.html

Try these for reading. Don't know of any step-by-step how-to sites.

Jack

[Jack_Hester]

PartsHunt -

Did you find something of interest? I'm satisfied that you would have found plenty to read with those links.

Jack

[Cotten]

Patience, Jack!

I ain't done readin' em yet, even what I edited myself!

They are all references to digest, and refer back upon, often.

(I am still stunned by Herr Elvenkemper's revelations in the Flywheel Workshop about the nature of Factor and chassis.)

I have a doomed personal project to put a 741 Scout stroked with a sportster (ugh) crank into a tragically butchered Beezer frame: Pick a factor,... any factor..!!

I don't even know where to start.

...Cotten

[Jack_Hester]

Cotton -

Everytime I browse the VI list, I see something new. You're right. Much to digest.

Jack

[partshunt]

I must thank you very much Jack for those intersting links and response to this ballancing question...... I read some of that stuff and its all out of my realm. I think best, I just farm these wheels out to some one locally when I find some one with a good history of success. Shipping them out of town be pricy. If mine ballance close to stock, I'm ok with it. I just dont want to shake loose my Timkin Boss loose again. Its been redone in Wiscosin with possibly a new boss insert or whatever thier secret fix is. All I can say at this point is I'v got excessive vibration......Joe

[Cotten]

Partshunt!

The first question to ask is "What factor will they use?"
Then watch their faces closely.

Your existing factor can be back-calculated quickly, and nearly always there is very little need to change it.

Frankly, if your motor is being overhauled and not put together from scratch,.... Balancing is a f*rt in the dark.

....Cotten

[59Panman]

Funny,

We had 2 almost vertical motorcycle hills, well seemed almost vertical named "Big Beezer and Little Beezer" back in the early 70's here in Castro Valley on Redwood Road on the parks property. I was 9 or 10 at the time and remeber trying to go up them on my 69 Yam 125 but didn't make it. I did a search and now I know where the name Beezer comes from! BSA

Ya learn something new everyday.

[FlatHeadSix]

Mark

Balance factor was critical when trying to get up those vertical hills. If you had the correct factor for your Beezer or Beemer you got over the top. I think the objective when calculating the optimum factor was to keep 100% of the weight of the motorcycle UNDER you at all times.

mike

[FlatHeadSix]

This is the result of an incorrect balance factor. The poor guy probably did not know how to use Cotten's formulas which resulted in a factor where the reciprocating mass is much greater than the rotating mass, as you can plainly see the two entities have swapped places. Excess vibration is not his biggest problem right now.

So, kids, do NOT try this at home!, this is a job which is best left to the professionals......

[Jack_Hester]

Cotten -

'I have a doomed personal project to put a 741 Scout stroked with a sportster (ugh) crank into a tragically butchered Beezer frame: Pick a factor,... any factor..!! '

Try the typical 50% factor used on street machines. I don't know if you remember me stating on one of the forums (FHP??) that my WLA wheels came out to a 44% factor with all stock components. Someone had done a nice job, as the wheels were closely matched. But, I'm curious as to what their former application was. I bought the bike in '76, voil of all sheetmetal, except two sets of tanks in a box of other good parts. Who knows. It may have had some racing history with that kind of factor. 50% is typical for H-D 45 wheels. Your project should run just fine with one somewhere in this range.

PartsHunt -

Methinks something is amiss. Are your two wheels original to each other? If the flywheels are assembled, unmatched, with one way out from the other, you will have a nightmare on hand. There probably won't be any smooth spots at all. If they are at least matched to each other, there will be several smooth RPM ranges. As Cotten has stated before, these V-Twins are very forgiving, no matter the factor. But, if the balance on each wheel is way different, don't expect any forgiving from it.

Do you know the engine history? Don't forget the tranny. Most overlooked single component in the bike. If the engine needs attention, the tranny warrants the same.

Jack

[Cotten]

FlatheadSix!

I don't own any factors!
My contention is that there is no correct factor. Just "most appropriate" ones.
Anyone can try this at home, and should be encouraged to do so.
Its a lot better than paying megabucks to some boutique that needs to pay for a bells'n'whistles Stewart-Warner so bad that they charge to change your factor for the sake of changing it.

Beezer's side-by-side vertical twins are a whole different animal than v-twins, especially when it comes to balancing. I cannot comment other than I'd like to learn more.

Jack!

My "Scout" project will be secured into the booger'd BSA frame kinda like the original arrangement. And it seems that the original factor for SportScouts (similar motormounts to my proposed build) is 85%.
That's why I brought up Matt Elvenkemper's reminder of basic theory.

Regarding differences between wheels,...I have yet to see the need demonstrated. It's still only one rotating mass in the equation.

To All:

Acute American V-twins are unique to balancing techniques because of their inherent simplicity.
Pistons do not have to weigh the same, as opposed motors require,... nor rod tops (they better had not!),
The motor doesn't even 'know' it has two rods nor two pistons, as it has only one crank 'throw'.
There is only one reciprocating mass, and only one rotating mass addressed by the traditional balancing technique.

It is traditionally treated as a "single", because there is only one crankpin.

(Please remember also that balancing technique does not address what the rider feels, only internal motor vectors.
Partshunt! If you feel vibes, there is a mechanical problem independent of balancing.)

V-twins are extremely forgiving of wide factors.
In fact, varying the factor allows for different character of motors, even when of the same design. A low factor balance job can offer a quick-revving hotdog motor, while a higher factor produces a strong cruiser. (Perhaps this iexplains the BSA hillclimber phenomenon, I really do not know.)

The preferred factor of modern OHV builders can range anywhere from 50 to 60%, no matter what the chassis or motor might be! Hearsay rules (insert frowning emoticon).


...Cotten

[FlatHeadSix]

Sorry Cotten,

My last post was a sarcastic attempt to reinforce all the points you already made in this thread, and many previous threads, about how little difference it seems to make when trying to change the balance factor on a single pin V-Twin. Changing the factor will not make your bike flip upside down, on a hill or on the highway.

And I was not trying to imply that you owned or invented any of the factors, I was referring to the fact that you have so gratiously explained them and provided detailed explanations for understanding the formulas. I, for one, greatly appreciate all that you and Jack and others have provided us.

I was just trying to get you guys to lighten up a little bit. After all, this is a hobby (for most of us) and its supposed to be fun!

Seriously, I do have a question related to this topic. If you are experimenting with totally mismatched components, like sportster wheels in Indian cases, its easy to reduce the rotating mass by removing metal. What if you need to go the other direction?, can you add weight to the wheels?, or do you junk them and find a heavier set? Also, what affect does total weight have? Balance factor is a ratio, you could have the same "factor" with a set of components that weighed 10 pounds or a set of proportionally heavier components that weighed 15 pounds, would the end result be the same?

I have always believed that the balance factor went hand in hand with how the bike was going to be ridden and used, kind of a rider's choice thing like the "city gearing" or cam options. If you are looking for quick throttle response and high revs then lighten the flywheels, if you want more low-end torque and steady pulling power then you want the heaviest rotating mass you can get away with.

mike

[Cotten]

Mike!

Sorry I missed the humor, but after reading so many bizarre posts on the web (like "algae growing in sparkplugs"), I never know when someone is kidding.

And yes, factor is independent of total flymass.

Some flymass can be added by "plugging and stuffing" with "Mallory metal", but probably not enough to do anything but change the factor. With luck, I shall be able to raise my sportster (ugh) wheels's factor by tapping and filling existing holes with common threaded stock. But since the pistons will be tiny anyway, I won't know until I put everything on knife-edges (someday,... *sigh*....)

Flymass stores energy, allowing torque to be applied easily. More is better for a machine that must pull a very heavy load, like a full bagger or a hack. But it comes at the expense of rapid accelleration. A light bike (and rider) can use light wheels, optimize breathing and such to run circles around a stocker.

I have a set of S&S stroker wheels that are just too light for sidecar duty, and I have considered screwing a ring of steel to them. (But geez, a set of T&O "Torquemonsters" would be a lot more convenient!)

The question of appropriate factor really only comes up when the chassis is altered. Otherwise, 57 to 60 % is pretty universal for a Pan.

....Cotten

[partshunt]

To answer Jacks question. "is it a mismatch?". The answer is probably gotta be a yes. Its a 54 right case and wheel with a Timkin New left case and 55 left flywheel and Timkin sprocket shaft. When you take it off idle in nuetral, (stoped) at 7-800 rpm it couses the front end to shake in sync with the fork springing. So, ok, I run in the new rebuilt engine in for about three hundred miles below 60 MPH. Last ride, I got brave and took it up to 75 MPH and there she shook, big time vibration. Enough I think it will tear that Timkin Boss out. It was already repaired for a loose boss. Dont want a repeat and havent checked if its ok yet. I'm afraid to even look in there right now......Joe