Help identify Excelsior flywheels

[Scooter6]

Good evening,
I need help to identify my Excelsior flywheels. I tried to used them in a 1920 engine, but they are too wide using the 1916 and up crank pin needed for the correct connecting rod spacing.

I am in need of 1916 and up flywheels. 1915 may be the same but I do not have 1915 parts book to know.

These flywheels are 2.790" measured across the outside at the crank shaft thrust faces when assembled with the 1916 and up crank pin.

I have found pictures of two types of single cylinder flywheels and neither look like these. I have not found any twin cylinder flywheel pictures that look like these.

Mine only have counter weights on the inside. Refer to attached images.

I think they are single cylinder flywheels because they have 1085 marked on each side weights. The single parts page shows 1085 for the single. I do not know why both of my left and right have the same number but it sure looks like both are marked 1085.

Please let me know what you know.
Thank you,
Scooter

flywheels outside.jpg flywheels inside.jpg

[exeric]

Looking in my Excelsior parts books, your flywheels are P.N. 1177 (right side wheel) & 1178 (left side wheel) for Excelsior Twins. Those numbers are good from 1908 - 1920 and probably to 1924.but there are different letter prefix's i.e. B, D etc. so there may be some differences that are not made clear in the parts books. I would bet the casting are the same for all years, but again, there could be minor changes. Fellow AMCA member, Gene Harper could provide better knowledge as he has been deep into many Excelsior motors. Also, I looked at the crank pin, drive, shaft and pinion shaft I have and they are worn out junk. They are hard to find in decent shape.

[gharper]

Eric, you're correct on the casting, same one used on all the twins. However, there may have been slight differences on how they are machined and significant differences in how they were balanced over the years. Scooter and I have been in touch.... His flywheels are odd, in that they have a counter weight on only 1 side of each wheel, which indicates a single. However, the 2 holes on either side of the crankpin are the shape of the twin wheels. So, once again, Schwinn was doing mystery things over the years. Scooter, you definitely need wheels that have counterweights on both sides of each wheel. I'll have to drag out my remaining spares and mock up a set of wheels and get a width dimension,

[Scooter6]

Good evening,
Thank you for the replies. I have also reached out to another member with the question if pre 1916 flywheel halves interchange with 1916 and up or if the alpha prefixes in the part numbers actually define a difference.
I am compiling as much information as I can and will publish what I find so futures can know. So far, I have not found a set, just one half that is likely to be twin and not sure of vintage.
Thank you for your efforts.
Scooter

[Scooter6]

I am adding more information that I cant guarantee is accurate, but will be helpful to others and I invite people who know more to add more. I do not believe early (thru 1914) flywheel halves will interchange with later (1916 and up) flywheel halves because of the early having shallow crank pin taper depth when installing 1916 and up crank pin. I am not sure about 1915 but I think the flywheel halves will not interchange with 1916 and up. Refer to attached images for details.

I am convinced that although the numerical portion of the part numbers are the same through the years on some parts that the alpha prefixes are to be considered an identifier that today we would refer to as a serial number break or model break.

I have included images of my first set of flywheel halves that I believe are for the single because they do not have outer counter weights. Another way to identify twin from single flywheel halves is the twins have inner and outer counter weights.

Also, refer to the images regarding the web shape around the crank pin. The singles have two radius corners and the twins have a continuous radius. However, I have not found a parts book image showing the single flywheel halves I am posting, but I have found a parts book page showing the early twin to have the two radius corners same as my single flywheel halves and an outer counter weight. Very confusing. The parts page image I have is hard to see, but I believe it shows the outside of the twin right flywheel based on that it appears the oil groove on the pinion thrust face is visible and a counter weight is visible.

Another way to identify pre 1915 flywheel halves is the counter weights are thinner and the inner counter weight is smaller. Refer to attached images.

Another way to identify pre 1915 right flywheel is the early will have oil groove on pinion shaft thrust face. Refer to attached images.

If I can ever get a correct 1916 up set, I will publish dimensions from the assembly. I have received measurements from gharper and another person that a correct 1916 up crank assembly measures approximately 2.650" to 2.670" across the pinion shaft thrust face to the sprocket shaft thrust face. If you try to use early flywheel halves with later crank pin the assembly will be approximately 2.790".

Gharper has provided crank pin measurements for me to be 2.760" shoulder to shoulder (not including the threads) for the twin and 2.642" shoulder to shoulder (not including the thread) for the single.

Hope this helps others. Share what you know. Thank you to those who have contributed.

Thank you,
Scooter

Thank you, right flywheel crank pin taper depth.jpg right flywheel thread protrusion.JPG left flywheel thread protrusion.JPG left flywheel crank pin taper depth.jpg

[Scooter6]

adding images of front and back of twin and single flywheel halves.

left and right twin flywheels insides.jpg left and right twin flywheels outsides.JPG single flywheels outside.jpg single flywheels inside.jpg