Motorcycles

I walked into Don Vesco's Yamaha in El Cajon when I was 15 years old to buy a Helmet. He hired me on the spot. Sure learned a lot working for him, for over 10 years. My Dad had died when I was 12 and Don Vesco was a very positive influence when I needed it most. He was almost a surrogate father or maybe a Big Brother to me.
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BACK TO THE MOTORCYCLE BUMP STARTER.

COPPIED FROM ASK BING AI

If a 2.5 inch wheel is spinning at 1750 rpm, and it is driving a 25 inch diameter wheel, we can calculate the RPM of the larger wheel using the following formula:

RPM small RPM large=D large D small

where RPM small is the RPM of the smaller wheel, RPM large is the RPM of the larger wheel, D small is the diameter of the smaller wheel, and D large is the diameter of the larger wheel.

Substituting the given values, we get:

RPM large=175 rpm

Therefore, the RPM of the 25 inch diameter wheel is approximately 175 rpm when driven by a 2.5 inch wheel spinning at 1750 rpm.

IF A WHEEL IS SPINNING AT 175 RPM, WHAT IS THE MPH?

Here’s how to calculate the speed:
  • First, we need to calculate the circumference of the wheel. The formula for the circumference of a circle is C = 2πr, where r is the radius of the circle. Since the diameter of the wheel is 25 inches, the radius is 12.5 inches. Therefore, the circumference of the wheel is:
    C = 2πr
    C = 2π(12.5)
    C ≈ 78.54 inches

  • Next, we need to calculate the distance traveled by the wheel in one minute. Since the wheel is spinning at 175 rpm, it will make 175 revolutions in one minute. Therefore, the distance traveled by the wheel in one minute is:
    Distance = Circumference × Number of revolutions
    Distance = 78.54 × 175
    Distance ≈ 13739.5 inches

  • Finally, we need to convert the distance from inches to miles. There are 12 inches in a foot and 5280 feet in a mile, so there are 63360 inches in a mile. Therefore, the distance traveled by the wheel in one minute is:
    Distance = 13739.5 ÷ 63360
    Distance ≈ 0.217 miles
Since there are 60 minutes in an hour, we can multiply the distance traveled in one minute by 60 to get the speed in miles per hour:
Speed = Distance × 60
Speed ≈ 0.217 × 60
Speed ≈ 13.02 mph

Therefore, a wheel with a diameter of 25 inches spinning at 175 rpm will travel at a speed of approximately 13.02 miles per hour

And I dare anyone here to push a 400+ lbs motorcycle 13 MPH and bump start it side saddle.
 
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Does anyone out there think a little flywheel mass will help or hurt the Bump starter.
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Flywheel mass will likely only matter if you can get the thing spinning before you connect it to the drive roller, but I'd guess the wheel on the bike has plenty of inertia and a flywheel will be a waste.
 
You might be right. the extra mass might make it harder to get spinning.
But the electric motor will only be starting the rollers and rear wheel in neutral, or at least with the clutch pulled in.
When everything is up to speed and the clutch engages the extra flywheel mass might help to keep it spinning without lugging the electric motor.
 
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If it's a decently tuned motor, it ought to start almost instantly. And I hope you're using a starter motor strong enough to turn the bike over. If you have to small a starter motor them a flywheel will give you more time before it stalls, but in theory, not much else.
 
If I'm not mistaken, the early BSA Rocket 3s were absent of an "electric foot".

When Honda came onto the multi-cylinder scene, these BSAs and the similar Triumph Trident triples got quickly upgraded to include electric starters.

My T150V Trident (which has no electric starter) is solely responsible for teaching me the value of meticulous tune-up skills, and introducing me to the Zen Art of Mechanical Balance. Unlike Rodney, I ended up with short and skinny, and I was -- when I first got the Trident -- about 135 lbs soaking wet. If I didn't have things set up completely right, my bike and me went nowhere.

These triples have three Amal carburetors that require careful synchronizing (the riding fun doesn't start until you tickle them, and then your finger smells like petrol for an hour of so), three independent sets of points, three separate coils, three separate condensers all powered by a wiring harness that was personally engineered by the Prince of Darkness.

Kicking 750cc to life on a 450-plus pound tippy lump makes guys dream of roller starters.


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Three and four cylinder engines are easy to kick over compared to some large twins and even worse BIG old high compression singles. My current antique bike is over 100 cubic inches and not too bad. But, I'm over 250# and have been kicking bikes for 60 years. When the kicker stops 1/2 way with all my weight on it, I know the crankcase is too full of oil... When I can't kick 'em over any longer, I will declare myself OLD.
 
This BSA Trackmaster Framed Half Mile/Street Tracker I've had for over 50 years Has a 3/8" stroker crank and .80 over pistons making it an 810CC 11-1 compression Twin. If all is right and warm it starts fine with the kicker. But I did Break my Achilles tendon 2 years ago. And no, it's not a drip pan under it, I had just changed the oil.
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Ira said:
If it's a decently tuned motor, it ought to start almost instantly. And I hope you're using a starter motor strong enough to turn the bike over. If you have to small a starter motor them a flywheel will give you more time before it stalls, but in theory, not much else.
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My plan right now is to use this Vintage 1.5HP old heavy (50lb) GE motor, with a starting capacitor the size of a modern 1hp motor..
Since the old motors were rated Continuous instead of peak HP, it might be equal to a modern 3HP. The motor sprocket I'm using has a 2"x1.5" hub and the Olympic Weight Plates. (Bar Bell weights) have a 2" bore. So it would be easy to add 5-10 or mor LBS of rotating mass to the motor. The 10 lb. weights are 9" in Dia which would be a perfect fit without being to large. I did just oil the bearings.
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More parts showed up today for the Motorcycle Electric Bump Starter.. The sprockets came in from Surplus Supply, Bearings from Ebay, and the two chunks of 2.5x2" 6061 round stock aluminum came from Amazon of all places.
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Time to get started on the lathe tomorrow. 1 inch of the aluminum slugs will be turned down to press inside a 12 inch sections of the Treadmill rollers.
Then the opposite ends will be turned down to 1.5" for the bore of the sprockets to slip over. Then bored for the bearings to be pressed in.
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My biggest concern right now is drilling holes in the sprockets to bolt them to the hub face. I ordered weld on sprockets with a 1.5 bore that would normally weld to a steel keyed hub. Since I am driving the rollers and not the shafts, I need to bolt the sprocket to the hubs, and then bolt the hubs into the tubular roller. The bearing shaft will be mounted stationary in the truss frame. Some sprockets are just tooth hardened, but these things I can't scratch with a file. I just now ordered 3 new Bosch 1/4" Cobalt M42 bits and I hope they will (CUT IT) literally. I would hate to have to heat these new sprockets and burry them in sand over night to anneal them and then try to re-harden them again after drilling the mounting bolt holes.


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Upper picture is shafts and rollers as they came from the Treadmill..
Shafts have already been cut to fit, rollers will be cut on one end to install the drive sprocket/bearing hub, with the stock treadmill bearing on the non drive side.
 
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Finished up the lathe work today on the sprocket/bearing hubs. .
Here's the back side that will be pressed into the shortened Treadmill rollers with the bearing installed.
IMG_20240125_154446197.jpgIMG_20240125_154732647.jpgIMG_20240126_150910646.jpgIMG_20240126_150927057.jpgRoller tube fitting.IMG_20240125_154526231.jpg
Then I did it all over again.IMG_20240126_152100623.jpg
Next I flipped them over in the lathe and cut the shoulder for the sprocket to sit on.
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Then I get to drill the mounting holes in the hardened sprockets. Oh fun. and then drill and tap the aluminum hubs for the sprocket mounting.
While all this was going on, I also mounted wheels and a motor plate, then cleaned up and painted the frame. Gun Metal Grey Acrylic Enamel left over from my CJ5 project.
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"Keep Moving Forward.
 
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Re-Purposed treadmill to Motorcycle Bump Starter in 12 easy lessons.
I got the bearing spacers all cut and the Rollers cut to fit today.
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Set screw collars hold the entire assembly together. Once installed in the frame work they are held captive by the frame and gusset plates.
I still need to drill the sprockets and drill and tap the hubs. Then it can be assembled.
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I got a pretty good texture on the rollers with the knurling tool in the lathe. Just a little traction.
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Cobalt M42 Drill bits showed up today, they cut through the hardened sprocket just fine.

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I got the hubs drilled and tapped and the sprockets mounted.
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Then re-assembled the rollers with the hubs, bearing spacers and set screw collars.
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I then drilled and tapped and Allen bolted the rollers to hubs, locking everything together.
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I got the old GE KC 1.5 HP motor cleaned up and painted.
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Then got everything laid out and ready for a final assembly tomorrow.
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Inferno said:

Lots of motorcycles here in India. I do not recognized them (not what we have in the USA). Here is one that stood out to me. ​

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The red one is a Royal Enfield 650 vertical twin ( think clone of a 60's Triumph 650). Enfield has been made in India since about 1954 under license from England. Enfield started out making 350 & 500cc singles for the Brit military. Would like to have one of the older 500cc singles..Enfield stopped making them when they went to the 650c vertical twin.
 
Royal Enfield still makes the 500 single Bullet. Unchanged since the 50's other than modern carbs and ignition. They have branched out in the last couple of years with several new models. They also export Speedos' Tachometers , gas tanks and other parts for the early BSA, Triumphs and Nortons. I had a set of BSA Smith instruments rebuilt for $200.00 in the 80's They never did work right. A couple years ago I ordered a Smith Speedo and Tach with the new cable and drive gear for my BSA Rocket 3 from India. $54.00 total, including shipping. They even say Made in England on the face. And work better than the originals from England.

Motorcycles | All New Model Motorbikes in USA | Royal Enfield

Royal Enfield USA - We have been creating modern classics since 1901. Manufacturers of the Bullet, Classic, INT650, Continental GT, Himalayan and Thunderbird series.
www.royalenfield.com www.royalenfield.com
 
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