80" lightened flywheels balancing

[cdf6333]

I'm rebuilding a 53 Chief engine which was a hot rod in the 50-60-70's. I've attached a couple of pics of the flywheels. They've been turned thinner by a lot and a bunch of holes were drilled to attempt a balance. The counterweight holes have been filled and welded. The rods are early, pre 46 Chief, and polished. Usually I balance these to even, HD style, but these aren't even close. I'm still about 4 ounces "heavy" on the piston side and I can't find any literature recommending this type of balance. I always ran 2-4 oz heavy on the counterweight side in all my 80's. The cams are wild, similar to Shunks but with a slight "hook". Very interesting engine, always from NJ and supposedly ran into the 70's and I'd like to do it the way it was, if I can back it up with something. It has HD manifold flanges welded to the cylinders to run a 1 1/2" carb. Has anyone run an 80 with a lighter counterweight?

[hairynob24]

I have seen a 101 like this ,it goes like stink ,Fly wheels came out of Europe ,any photos of how the bike looked back then ?Rob.

[cdf6333]

No pics as it's apart now. We took it apart to fix leaks. I'll try to remember to take a few when it's back together as we're not touching the looks of the Chief.

[Knotthed]

cdf,

Maybe you could post some more pictures of the cams and such? maybe even a side profile of the flywheels with a thickness measurement.

very interesting indeed!

My guess is she is gonna jump around on the side stand, but be smooth at high rpms.

[cdf6333]

I'll do that later, but I guess my question is still has anyone else run a 80" Chief with what seems like 45-47% balance factor? I have some more info. Jules Frohlich of NJ built the engine in the 60's or early 70's. It was balanced at Simonec in Paterson NJ, Gasoline Alley the area was called then. It was ridden to Laconia and a bunch of other rides. Still has a nutty footshift and hand clutch set-up, with an external, fast angle, "worm" pressed into the primary.

[kval]

Bob
is that the mother of pearl white bike? Jules had all his motors balanced at Simonec and that bike had really high compression, kept breaking the kicker arm

[cdf6333]

Yep, this is the one. Have you ever heard it run?

[T. Cotten]

cdf6333!

I'm out of my league here, and a bit confused.

It appears that the wheels are lightened around the pin, which would raise the factor, yet you believe these are quite low?

Have you put them on knife-edges, and back-calculated?

....Cotten

[fillibuster]

cdf6333!

I'm out of my league here, and a bit confused.

It appears that the wheels are lightened around the pin, which would raise the factor, yet you believe these are quite low?

Have you put them on knife-edges, and back-calculated?

....Cotten

I agree, there's obviously a different math at play with the factors suggested. I'll take a wild guess at the factor he's got with what the pix show: 75%,
give or take 5.......
have you had the wheels magna-fluxed? checked for cracks? at the shaft tapers.

[D.A.Bagin]

Jules is still around, why don't you call him?? He would probably like the call even if he doesn't recollect this build. Thanks for the reference to Simonec and Gasoline Alley, brings up old memories, as I lived in the next town over.

[cdf6333]

Cotten and fil, The wheels are thin, cut down to an inch. Origs are about 1.270 and this is where the uneven weight reduction happened. I'll attach 2 pics. It also is using early, pin hole top, rods which are a bit heavier than later slot tops. I'm still, even with all the crank pin side holes professionally done, about 4 ounces heavy on the crank pin side . I would have to remove about 4 more ounces of weight from the crank pin/piston side to get 50% balance ( 1 piston, pin, rings & clips). I'm used to plus 2 - 4 ounces counter weight side my last 40 years doing this which I call 52-58% factor. I've also never done a lightened flywheel 80, especially one that was well known as a runner 40-50 years ago!

[cdf6333]

Drew, I spoke to Jules and of course he remembered everything about this build 50 years ago! He still sees the orig owner a couple times a year, even thou the owner moved near Philly. Jules is still doing mags and old, old generators, remarkable guy!~

[kval]

it has been quite a long time ago, it was up at Jules place, he was getting it running for the owner. I wanted to buy that bike for a long time, but the guy would not sell. it sounded REAL STRONG

[T. Cotten]

CD6333!

Shaving the wheels alone does not appreciably affect the factor, as factor is independent of total flymass: a ten pound set of wheels and a twenty pound set of wheels can both have the same factor.

And the military method of hanging one piston assembly on the wheels and then correcting the balance does not result in a 50% factor. More like 64% on a Chief.

Your rod tops can be weighed while assembled, using appropriate V-blocks beneath the wheels, so that the wheels can be rotated to where the weighed rod is level.
Then with the weights of the piston assemblies, you will know your total reciprocating weight.

By placing the wheels and rods on knife-edges, you can then stack weights on wristpins in the rod gudgeons until it comes to 'balance". That weight, plus the rod top weights, is then divided by the true total reciprocating weight to give you your true factor.

Then you can decide if you wish to change it.

A general discussion of static balancing can be found at [ur]http://virtualindian.org/1techflywheel.htm[/url].

....Cotten
PS: The next time I build "knife-edges", I will use ground 1" round stock instead of planer blades!

[cdf6333]

Thanks Cotten. But shaving the wheels removed a lot more from the Counterweight side than from the pin side, as you can see by the drilling. The scary part is that it was done by one of the top engine balance shops in NJ, way-back-when. I really don't want to change anything without a real good reason.
I'll re-read the article, I always called military method 50% and found orig Indian to be between 2 -4 ounces heavy on the counterweight side. My thought was inertia, but HD with much heavier wheels and weights, balanced even.
This bike is only going to be a bar hopper, I'm just trying to get it close. Chuck Myles had a Chief way-back-when that had 74 flywheels about 1/2 " thick. It was out of his 120 MPH Indian is stock trim. He made 6 more sets, I bought 1 and sold it to Wayne Mauro in NJ, who I think still has them. Not sure if they went in an engine yet.