Knucklehead MPG

[Lonnie]

Uh-oh!

I have purchased and installed several sets of Cotton's floats and did not know I should have recorded the fuel mileage - reckon I'm in the doghouse.

My '42 FL is getting around 35 mpg - hard to check it accurately since the 24T trans sprocket with whatever speedo gear is in the trans indicate about 50 mph when everyone else says I'm traveling over 55 mph. (Carb is an M-75 with an M-35 venturi). Nevertheless, the 35 mpg is a fairly close estimate.

None of my other old bikes have a working speedometer.

Lonnie

[Chris Haynes]

My mileage is a lot better at 55 than it is at 80.

[T. Cotten]

Lonnie!

Fear not! You were not one of those who responded to my requests for mileage records!

I would clarify, and identify, all those deadbeats for all, but this Forum has discouraged it.

The vintage industry cannot protect itself through the AMCA.

...Cotten
PS: Oh Yeah, back to topic,

It's all about record keeping folks. Clean, honest, uncompromised, impartial, and ACCURATE readings taken with the least possible variables.

Who among us thinks thinks two speedos will register the same?

[koanes]

It's easy to use the mile markers on the highway to check the accuracy of your odometer. Anything over 5% is significant and should be considered when you are checking MPG.

[knuckleheadtim]

I've gotten as high as 42 MPG pulling a sidecar. Not only is the float important, but the ignition timing will drastically affect mileage. If you are running light flywheels, don't expect to get more than about 25 MPG.

[motorpickle]

Pardon my gas

I switched to Cotton floats about 2 years ago on everything I own or work on. 46 FL with sidecar gets between 20-25mpg(a real pig),41 F solo gets 30-35mpg(I can live with), 48 WL solo gets 35-40+(a pleasure). I burn premium in all three. I am in a reformulated zone so I get what I get. Cotton--how does the float level affect mileage? or did I misunderstand a statement?

[indianut]

You are Wasting Money putting Premium Fuel in a Flathead.

[c.o.]

You are Wasting Money putting Premium Fuel in a Flathead.

Guys on their modern machines get a weird look on their face when I grab the regular nozzle at the pumps when it's time to top up the flattie....

[T. Cotten]

Motorpickle!

There are some things that we just have to assume that Schebler and L&L worked hard to get right, or at least close, and one is float level.

But it doesn't mean we are forbidden to experiment.

In the days of boatanchor brass floats, setting deep to a trial-and-error 'sweetspot' meant tediously splitting hairs. But when I first began cutting Nitrophyl, I was shocked that folks would give me glorious feedback of improved performance, but then announce that they had set the float anywhere from 3/16" to 3/8"!

If seems that once the float actually floats, the accuracy of the setting seems to lose importance, by the seat of the pants anyway.

Back in the day, they could only make a float so light. Cork and collodion was it.
But who knows, maybe with the latest super-light material, a shallow setting may provide the extra reserve volume that flat-trackers found lacking enough to build "pregnant" bowls.
It is up to the individual to tinker and enjoy the possibility.

I shall debut at Davenport the lightest Linkert floats ever produced, of an exclusive new material that has only been available for a little over a year. (The obsolete formula is beginning to fail in the latest fuels, and I replacing free of charge any DURABLE floats returned to me for swelling.)

...Cotten

[Chris Haynes]

Motorpickle!

(The obsolete formula is beginning to fail in the latest fuels, and I replacing free of charge any DURABLE floats returned to me for swelling.)

...Cotten

How about new, in the box floats that haven't been installed yet? Or do I have to build the carburetor then have a down machine while I wait for a replacement?

[T. Cotten]

Chris!

Sorry, I can only replace those that swell, as the original formula "Armstrong" floats did.

Nor can I replace those that are broken by clumbsy fingers!

Ironically, all "bloats" so far have occurred east of the Mississippi River, with one exception from Texas. And please note that all had been in service longer than most batteries last.. or even tires for some riders: still pretty good for a rubber product.

In an "emergency", a little sandpaper taken to the left side of the float will return it to service, and probably for a good while.
But I need to follow the fuel trends on the planet, as well as my customer's satisfaction, so the return of all samples of swelling are greatfully appreciated, and immediately replaced with the latest material.

....Cotten
PS: What must folks with S&S carbs do when their floats crap out?

[knuckleheadtim]

I was having serious issues with a brass float in my '46 Knuckle with an M74-B. I had to drop the float to 7/16" to get the fuel level correct in the bowl so the air bleed holes in the main nozzle would kick in at the right time and give a smooth transition through the ranges. It ran good at slower speeds, but ran out of fuel after about 1/2 mile on the highway (pulling a sidecar). I put in one of Cottens floats and set it to 1/4"; low and behold, it runs great and doesn't run out of fuel at high speeds. Apparently, the brass float couldn't drop enough to open the needle valve all the way because I set it low to begin with. Long and short, the weight and setting are both critical to proper performance.

I've gotten as high as 42 MPG with the hack before oxygenated gas. I still get better than 35.

Thanks, Cotten!