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mrriggs

Homemade Motorcycle Dyno

74 posts in this topic

My cousin and I started this project almost two years ago. I was talking to him one day about building a dyno, I had everything figured out but the roller. He was working at an excavation company at the time and said he had just the thing.

roller01.jpg

roller02.jpg

roller03.jpg

It cost us $20 and came with the bearings. He got some metal for free from his dad and welded up a frame for it.

Dyno04.jpg

The computer end of it is pretty simple. A single tooth is welded to the drum and a magnetic pickup from a distributor is mounted to the frame to sense the tooth. That is hooked to an inexpensive datalogger which records the run. Then the raw data is dumped into Excel where all the calculations are made and the chart is printed out.

DemoChart.JPG

That chart was just to test the program. We only put a bike on the dyno once and the computer glitched out so we didn't get any real numbers. The drum is out of balance, as you can see in this video clip.

All this was done in a matter of days but then other things came up and he went off to school. The dyno has been sitting in my garage untouched, covered with junk, for the last couple years. I have everything needed to balance the roller, and he collected all the parts for an adjustable wheel chock. A couple nights ago I cleaned up the garage and cleared off the dyno. It's time to get this thing done. I figured that if I posted it here then I may stay motivated this time to see it through.

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What do you use for a standard? I see how you could compare run to run but how do you know what torque is being produced? Awesome job!

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What do you use for a standard? I see how you could compare run to run but how do you know what torque is being produced? Awesome job!

When you know the inertia of the drum, you measure the acceleration then calculate the torque. I have a rough calculation of the inertia based on the size and mass of the roller. Once it is all balanced, I will directly measure the inertia of the roller with some fishing line and weights. Getting the exact number isn't really that important. All dynos are good for is compairing one run to the next.

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I was wondering what happened to this project. Good to see you getting back to it. :thumbsup:

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Dam im glad you dug this back out. we'll try to keep you focused. Now go back to work. !.

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The level of creativity on this site never ceases to amaze me.

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Riggs, I'm glad you found your way over here - this is some cool shit

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The level of creativity on this site never ceases to amaze me.

Agreed. Pretty wild (and very cool!).

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Holy chit thats alot of ciphering but it is really cool to see a homebuilt rig like that especially if you get it all ironed out and working good.

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Years ago, I thought it would be a good money maker to load a single wheel dyno into a pick-up truck or a trailer and drive around and let bikers (mainly sportbikers) flag me down and charge $20 for a dyno run on the side of the road.

Unfortunately, I'm sure the police wouldn't care for me doing that on the side of Rt15 and I'm sure Burger King wouldn't care for it in their parking lot either.

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Years ago, I thought it would be a good money maker to load a single wheel dyno into a pick-up truck or a trailer and drive around and let bikers (mainly sportbikers) flag me down and charge $20 for a dyno run on the side of the road.

Unfortunately, I'm sure the police wouldn't care for me doing that on the side of Rt15 and I'm sure Burger King wouldn't care for it in their parking lot either.

thats just when you take it to the little bike shows or even bike night at the bars, there would be your money. Beer bikes babes and did I say beer? Big egos also. think about it.

I bet my bike is badder than yours" well put your money where you mouth it...............lets do the dyno.................lol

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Years ago, I thought it would be a good money maker to load a single wheel dyno into a pick-up truck or a trailer and drive around and let bikers (mainly sportbikers) flag me down and charge $20 for a dyno run on the side of the road.

Unfortunately, I'm sure the police wouldn't care for me doing that on the side of Rt15 and I'm sure Burger King wouldn't care for it in their parking lot either.

thats just when you take it to the little bike shows or even bike night at the bars, there would be your money. Beer bikes babes and did I say beer? Big egos also. think about it.

I bet my bike is badder than yours" well put your money where you mouth it...............lets do the dyno.................lol

You are dead on. I bet you could make a killing at a bike night at a bar. If your lucky, you might even see someone get killed over it.

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My cousin and I were actually thinking about that when we started this. There is a big cruise in at the drag strip every Wednesday; cars, bikes, drag racing, and live music. A dyno would give the RUBs with big egos something to do besides sit on their bikes blipping the throttle all night.

Now that all my time isn't being taken up making alternator brackets, this is back on my list of stuff to get done. I've got some ideas for intake designs that will not only look cool but also perform well. Having a working dyno will really help the R&D process.

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Wow, time really gets away from you. It's been six years since we started this project. We were gung-ho for the first couple days then it sat, untouched, ever since. In the mean time I've drug home a bunch of machine tools and have been working on getting them all running. This dyno is the last non-functioning machine in my shop. With his Bonneville bike and my big bore project, it would be nice to have this thing up and running.

The next big hurdle is to balance the roller. I started the night by clearing it off and collecting all the necessary bits.

Dyno05.jpg

A guy I work with upgraded the wheel chock on his bike lift and gave me the old one.

Dyno08.jpg

I plan to dynamically balance the roller so I needed a way to spin it. A rubber tire mounted in the chuck of my old drill press makes for a simple friction drive.

Dyno07.jpg

I also made the mounts for the accelerometers. There will be one mounted to each bearing.

Dyno06.jpg

I've still got a few more little odds and ends then it will be time to see if any of this will actually work.

If anyone is curious, this is the procedure I will be using to balance the roller.

http://www.gofastforless.com/junk/DynamicBalancingExp.pdf

Please, Maxx, for the Love of God, DO NOT CLICK THE LINK! There is math, LOTS of math.

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I clicked on the link.... MY EYES!

my eyes...the goggles do nothing!

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Yeo really glad to see you back at this , been too long . Can't wait to see it working .

Have never seen anyone that has less fear of stepping out of the box . The drill press as a wheel drive would have never occurred to me ! Go man go !

Edited by Red Good

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My cousin came over today and we worked on the dyno. Got it all set up for balancing but the accelerometers aren't sensitive enough to pick up the imbalance. Plan-B is to static balance it so we can spin it faster for the tests and hopefully find some better accelerometers.

It wasn't a total loss. I did some dyno pulls on the drill press to check out my program. They were all very consistent, 1/4 horsepower and 1 lb-ft of torque.

DrillPressDyno.jpg

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I've got an old Alemite spin balancer head that I'v used for stuff like that before if you want to borrow it. It's sensitive enough that I have used it on things between centers on the lathe. The weight scale is calibrated for 60 mph on a 16" tire so the weight required scale won't be right but the strobe will be right on and after a correction or two you can figure the relation ship between the scale and what you want.

Dusty

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I've got an old Alemite spin balancer head that I'v used for stuff like that before if you want to borrow it.

Thanks Dusty, but I'm not sure that will do what I need.

I've been researching accelerometers and I think the ones I have will work if I can spin the drum faster. With the imbalance it had, we could only get it up to 14 mph. I did a quick and dirty static balance on it last night.

To measure the imbalance, I put a bolt on a magnet and stuck it to the heavy spot. Spun it perpendicular to the pivot and set a scale under it.

Dyno09.jpg

Then I turned some weights to match...

Dyno10.jpg

... and welded them to the drum.

Dyno11.jpg

Dyno12.jpg

Unfortunately, I didn't realize until after I welded them that I forgot to subtract the weight of the magnet I used when measuring so it ended up a bit too heavy. It's still a hell of a lot closer than it was.

I put the drill press on the second highest speed and spun it up to 40 mph. It was late and I was making a hell of a lot of noise so I shut it down for the night. I'll try it again on the highest speed which should be about 50 mph. I'm really surprised that I haven't burned up this motor yet. It is really lugging down to get this big roller spinning.

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I have been using a USB data logger to record the runs then loading the raw data into Excel via csv. It works pretty well but is a bit awkward. To simplify things I'm going to try to use the sound card in the computer as the input device. That'll not only make it simpler for me but for anyone else who wants to build a dyno.

I threw together a program today to convert a wav file into a csv in the same format as my data logger. That way I can record the run with the Windows sound recorder then dump it into my spreadsheet. If that works then I'll tweak the program to do the recording. Eventually, I will add all the data analysis and graphs to it so you won't need Excel. Just click one button, goose the throttle and bam, your table and graph pop up.

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Success! I just made a few pulls with the sensor plugged into the microphone jack of the laptop. I was using a faster speed than last time so the numbers are a little different. But still very consistent.

DrillPressDyno2.jpg

The first two runs had a bit of wheel spin so I was pushing down on the drive head for the third run which is why it's a bit different.

Now that I know this will work, I will write up a better program to make it all a lot more user friendly.

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It's been slow going. Like most of my projects, I'm reaching way outside of my current skill set. I've got a good picture in my head of what the program will look like. The plan is to make a full-on GUI written in Python. Just finished reading a book about Python and started fumbling through the code.

Today I made a functioning gauge "widget". You just plug in a diameter and number of tick marks and it generates a gauge. You move the needle by plugging in a single value that corresponds with the percentage of total travel. It's not much to look at yet. Now that the nuts and bolts are worked out, I will pretty it up a bit.

WAVdyno01.jpg

This is just the tip of the iceberg, there is LOTS more to do.

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