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Home Brew / Re: 1981 Honda Cm400T Conversion with Transmission
« on: March 24, 2020, 05:29:53 PM »Have really enjoyed the progress updates with this project, would love to see more photos! Plus that video you teased in your original post.
Wanted to throw my 2 cents in, I beg your forgiveness for my ramblings...
Appreciate that if the bike works its performance will leave a lot to be desired. Stock that motor put out 40hp,
I have concerns if the 2.8hp of that motor will be able to turn the drive line over.
Hopefully it works well enough to inspire you to move into phase 2 taking what you learned and building on it.
Halving the torque output of the motor (due to the 2:1 ratio from the motor to the cam gear) will not help matters. You might want to try a 1:1 ratio to start with.
With that said it's amazing what low power motors can be capable of. My first bike was a 1980 Puch Maxi, single speed pumping out all of 2hp. Was still able to manage 30mph.
My first bike with gears was a 2004 Aprilia RS50, cranking out a massive 12hp through a 6 speed gearbox. On flat ground 80 was doable, put a hill in front and 60 was it.
The transmission is going to be your best friend.
I am curious to see how much vibration is introduced by the now unbalanced crank lobes, hopefully minimal but excessive vibrations could cause premature bearing wear/failure.
If you have any plans to open the motor cases I would strongly suggest cutting off as much counterweight material as possible.
+1 on swapping the cam chain for something more robust, a quality 415 chain is more than up to the task. Ideally the motor controller has some sort of "soft start" function to reduce further.
Regarding batteries
I would use lead acid as a last resort, especially buying them new. The weight of a 48v pack would be 100lbs, you would also need to do a lot of work to safely secure them to the bike.
LiFePO4 has around 3x the capacity or 1/3 the weight for the same capacity. There are sources for used cells.
I would suggest leaving the clutch on the bike as an extra layer of safety, if a bracket gear or sprocket breaks you have the ability to disconnect the rear wheel preventing a lock-up situation.
Also where are you located? There might be some local resources that you could utilize.
Happy Building!
I greatly appreciate your input and support for this project. Photos will be coming, but not much has changed until I can get that crankcase back from my grandfather.
My grandfather and I did consider taking down some weight in the lobes for the crankshaft, but we're willing to revisit this if it becomes much of an issue for sure.
I'm also not too confident on the motor I currently am using for this application as it is small for what I'm wanting to do with it. I found it cheap online and took a gamble to see if it would worked on a rough idea I had and the video shows it seems like it will, but not sure once the weight is on. My theory behind the 2:1 E motor to the crank shaft serves the purpose of the rpm's from the small e motor. I know the e motor only has a peak of 4300 rpm's and the peak rpm's for the stock motor is 8500 rpm's and sticking with the stock numbers as much as possible, the gearing would have to be close to 2:1 for efficiencies and normal rpm's of the e motor.
If this does work, I do intended to put a bigger e motor on it, which I currently picked up a few weeks ago, that could work, but the battery pack is my biggest enemy as the cashflow isn't there for this project. I would love to do the LiFePO4 batteries, but the wallet says otherwise. We'll see what comes abount on the market places. I'm in the northeastern part of Indiana so there's a few junk yards, but not many that have the EV's like I would hope along with the companies realizing the value of the batteries in a wrecked out body, so shit out of luck at the moment.