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BLACK BELT
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Discussion Starter · #1 ·
Looking for one of these reasonably priced in the USA.

The only ones I've seen are $800 to $1,000 usd.

Prefer 220V, not battery power.

 

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BLACK BELT
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Discussion Starter · #3 ·
A. Build one!
B. Are you really that close to finishing the build? ;)
I might have to build one, but I've got way too much to do already.

Not just for the build bikes. I've got 7 bikes, and only 1 has an electric starter.

My right knee is pretty wasted from a lifetime of kicking 2-strokes and over 20 years of judo and roller derby.

I want a roller starter, for sure. Just for home use. And I want a 220V starter that you roll the rear wheel onto - then hit the remote switch with your foot to fire it up.
 

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lɐʇuǝɯᴉɹǝdx&#4
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Why 220v? Why not 120v if in US? If its battery powered, throwing in a charger to keep the battery topped up seems simple. Are you looking for something that can run with a really high duty cycle, and worried about the battery sagging? If so, a bigger (still 120v) charger / starter unit like garages use is still pretty cheap.

As to cost... yeah, its a low production item, essentially custom. Think about the time you'd spend building one, and the cost of getting all the parts together. I can't see anybody selling one for much less, but I might be willing to give it a shot just for giggles & education. Simple frame, some pillow blocks, a motor with a shaft pulley... can't be that hard, no worse than bodging together a some other tools I would like to build. Would come out looking like a Franken-starter, of course.
 

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BLACK BELT
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Discussion Starter · #7 ·
Why 220v?

Would come out looking like a Franken-starter, of course.
I've only seen 220V and battery power, but the 220Vs were made outside the USA. If 120V is an option, that's even better.

Not sure what voltage is on the starter that MikeGyver posted - which is also pretty Franken at $825 usd.
 

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lɐʇuǝɯᴉɹǝdx&#4
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Looks to me like its rigged for battery, with a generic DC (12/24/36v) motor. Fabrication looks good, nice heavy rollers, both driven, etc. Cost is high, but I'd expect its $200+ (maybe big plus) in parts and materials, and (unless he's cranking them out a dozen at a time) 4+ (again, maybe big plus) hours labor.

120v is certainly an option, just depends on the motor used. Something like a 1/4 hp motor as you'd find on a drill press or blower costs ~$80 bucks. Can be much less if you go with a used unit on eBay, but then shipping kills yah. Scrounging one is a good way to save, lots of tool / blower / pump / washing machine motors would do.

Similar power DC motors cost pretty much the same. Going with an AC motor does save money if you know you'll never want to run it where you don't have a plug, in that you won't need a 12v power source.
 

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Is my bike ok?
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It's gonna be hard to find a high amp 120v motor that is affordable. 220 will be much cheaper in the long run.

One of the tracks we used to run nostalgia races at had rollers in the staging lanes. Probably not something that'd work for you, but they initially were just powered by another vehicle. Whatever they were using to push the race car with. You needed the other vehicles brakes to hold the rollers still so the race car could drive off of the rollers, too. Though I doubt brakes on the rollers would be an issue with a bike. Push vehicles went away, but the track still uses the rollers. Now they're powered by a Ford starter motor ( which engine, I'm not sure, but it b looked like a standard sbf to me). The rollers were driveshafts with bearings pooped on both ends that just laid in a cradle. It was built so as to leave the frame work in the lanes , but the hardware was easily lifted and stores out of the weather. When they added the Ford starter they just welded a flex plate to one of the rollers and added a slit in the lane to accommodate it. Very low buck, but requires 12c DC. You can get step down transformers to bring 120v or 220v AC down to 12v DC, but a high amperage unit is probably going to hit $200 pretty easy.

Just tossing those things or for brain food.


Something else, some of the lighter weight cars had a hard time starting on the rollers. Traction issues. The tires would slip on the steel when the closed the clutch, but we're talking about American six and eight cylinder engines and rather beefy differentials and gear boxes that had to be spun up. Obviously the drivetrain on a bike is pretty low impact, but the amount of pressure on the rear tire is pretty low, too.

Do you have any buddies that play with small engines? If you can find a engine with a horizontal shaft, mount an $8 HF tire on to the end of it and rock on. A little imagination and you could set this up to be a one man show pretty easy. vvvb

http://youtu.be/xIed0D0DxpI

Judging by the sound of that 5hp (?) in that video bogging down, I don't think a small motor put of a still press, etc will do it. I do HVAC for a living. 1/4 and 1/2 hp blower motors will never begin to spin when powered up if you've got a decent grip and hold it still before you try to turn it. There's very little torque available there. IMO , you're not gonna rob a motor out of any common power tool and get it done. Except maybe a motor off a lathe or a mill.

But all said and done, a 220v motor like you mentioned is probably gonna be the cheapest route, considering the wattage you'll need, unless you're cool with DC and keeping a battery around.
 

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I used to build weird stuff when I worked in R&D. I think you need to start with some math. Take a guess how fast the rear wheel needs to go to start the bike, then use the wheel radius to find ft/min. Once you have ft/min you can calculate roller rpm from the radius. When you have rpm you can look at motors and maybe gain some torque through a gear reducer. Personally I think $2-300 would be a tough target to hit for a one off.
also you could give it some more mass like heavy steel rollers, that would cheat a little since the time you are actually loading the motor is small, you don't need more motor if you can use the inertia. I worked on an aircraft brake dynamometer that only used inertia to test brakes, the motor just spun up the system which had lots of inertia.
 

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lɐʇuǝɯᴉɹǝdx&#4
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Yeh, for a small motor I was assuming you'd run some reduction and a fair amount of flywheel mass. And even so, seems I miss-judged the power requirements.

How about this bad boy? http://www.harborfreight.com/3-hp-compressor-duty-motor-68302.html

3 horsepower for $165 seems a smoking deal (and yeah, its a 230v like Shiney said... go figure, man knows motors) and not like its gonna be running so much that you need worry about it busting (HF would replace it anyhow). I also noticed a lot of larger motors say they are "not for air compressor use"... not sure why, but I'd bet it has something to do with the resistance not being smooth. Starting an engine is an awful lot like turning an air compressor...

Edit - apparently "compressor duty" partly means its built to tolerate being turned on / off under load?
 

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Well, I couldn't help myself.

Lets say you need the bike going 15MPH to start. Thats:
15 * 5280 = 79200 FPH
79200 / 60 = 1320 FPM
A 5" roller has a circumference of 2(pi)2.5" = 15.7", or 1.3 feet.
1320 / 1.3 = 1015 RPM
A 2.5" roller has a circumference of .65 feet,
1320 / .65 = 2030 RPM

So you will probably need some reduction since most motors spin too fast, a small enough roller to match a typical 3600 RPM motor will have no grip against the tire.
A gearmotor would be best for this to both match the required speed and get extra torque.
However I like the idea of an old starter motor because it would be dirt cheap and just use an old battery from the shop. Still need a gearbox though.
 

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I don't think flywheel mass has any use since you'll be spinning the wheel/tire combo and that'll be enough of a flywheel effect
The wheel and tire won't be spinning fast enough to generate any real force. A heavy roller spinning at 1000 RPM will. If I remember right kinetic energy is proportional to the mass and velocity, in this case the velocity is important.
Otherwise you could just lift the back of the bike with the wheel spinning, drop the clutch and start the bike. But I'm pretty sure the wheel will stop right away once it engages the engine.
 

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V four honda whore
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Looked this thread up and did some googleing, and found an idea. Why not use car starter to turn the rollers? Even better if diesel one
 

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Stupid motherfucker
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EZ PZ. Buy a 12/24v booster/jumper pack. Buy a heavy diesel starter motor with a sprag clutch. 24v, massive torque, seriously not for the faint of heart. Design a pair of vertical aluminium plates, the start motor bolts between those, the two rollers (I'd grab, say, 120mm dia mild steel, and have the outside knurled while machining out a bearing carrier/spigot) bolt between the vertical plates with a pair of bearing carriers. Adapt a trio of chainwheels to drive both rollers off the starter motor (obviously disabling the throwout action), and run the starter through a remote button to the jumper pack.

That's how I've had mine planned in my head for ages now. Picking up a decent heavy truck starter motor is the only real hard part, but there's plenty of dudes with 24v systems in Landcruisers you should be able to find something that suits.
 

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Is my bike ok?
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There's many different 220v outlets, depending on the amperage of the circuit. Think dryer cord, window unit cord, range cord, welder cord,etc.

Some people call it 220, others call it 240. Just like how 110 and 120 are the same. The voltage varies within those labels, but yes, 220 and 240 are essentially the same.
 
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