Electric Buell racebike build

stamen

1 mW
Joined
Oct 13, 2014
Messages
15
Hi All,

What:
I've got a project that has been lingering around for a couple of years now and due to many personal moves and readjustments I never really had a chance to finish it. However, now I'm ready to start it back up and finish it for good. To make a long story short I originally intended it to be a street bike mainly, but after moving to Europe and learning that it is very difficult and expensive to register a custom electric motorcycle for street use I decided to make it a track only bike. It kind of works out better in the end and will be more fun because I can do more custom things!

Who:
A bit of background about me. I'm a Mechanical Engineer working in the motorcycle industry. Motorcycles are awesome! Electric ones even more so! :twisted: I'm from Chicago, but now I'm in Europe (Austria). I have a solid understanding of EVs and electronics, but I'm hoping to learn some helpful things along the way here. I've been lurking on ES forum for quit some time so I decided to share my build.

Goal:
I want to use this thread to share my build progress, get some advice on certain things, and hopefully meet some local EV enthusiast. As far as the bike goes I want to start out with some track days to check out the overall performance in the Summer of 2019 and then if all goes well maybe some amateur racing. I have some future plans for liquid cooling after the build is completed and the weaknesses are identified.

I already have most of major components that I had planned to use a couple of years ago when this thing was supposed to be a street bike. So there's no turning back at this point. I do believe that I can build a decent track bike with what I have as long as I keep the overall weight down ~ 370 lbs, ensure proper gearing, hopefully do some performance tuning (dual Sevcons ??), and of course keeping the electrons flowing :lol: aka thermal management. Anyway here is some more info and pictures. More to follow.

Bike:
Donor chassis: 2004 Buell xb12r + a custom steel tube "sub-frame" to support all the electronic bits and the swing arm as well. Since the original Buell XB chassis uses the engine as a stressed member I needed a way to bridge the gap to the swing arm.
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So this is what I came up with. The pink part is simply where the OEM exhaust should end up for visual reference of the ground clearance.
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The steel tube frame is made from mild steel 1020 DOM 1" OD tubing with 3/4" OD tubing for the support members. The motor mounts are made from 2D laser cut steel plates and welded to supporting points on the frame.
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The swing arm mounts are 2D machined also out of mild steel and welded to the frame at the rear. The whole thing is a tad over designed but because it's connecting the frame to the swing arm and holding mass I wanted to be sure it would have enough strength and retain or improve the entire vehicle stiffness. I think I may have actually increased it. The total weight of the welded "sub-frame" is ~40 lbs.
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Suspension: Stock Showa fork and shock for now, but plan to upgrade eventually and maybe even swap the entire front end for some dual rotors and Brembo brakes.
Aero: Plan to get a full race fairing.

Now for the EV part of it..

Motor: 2014 ZF75-7R with higher temp magnets (SPM)
Controller: Sevcon Gen4 Size 6 72-80V Nominal
Batteries: 2012 style Nissan Leaf modules x 14 so ~6 kWh @ nominal voltage. I don't plan on building a "battery box", since this will be for racing only, unless I need to go with liquid cooling. I will still make some kind of debris shield out of CF or Fiberglass.

Charger: TBD will be off-board for sure (thinking power supplies in series and parallel I want to build a 7-10 kW charger) If my logic is correct with a 10 kW charger I could recharge in about 40 min (which is the time between track day session) if I charge at 1C-1.5C at the cost of reduce cycle life. Also I would probably need to keep the cell temp. down in order to charge at those C-rates so maybe some liquid cooling or advanced air cooling will be necessary? What do you guys think?

BMS: TBD not sure yet if I will use one. I know the Sevcon can do LV protection but I'd be worried about the over charging.

At the moment I am assembling most of the mechanical parts of the bike together to get a rolling chassis. The motor mounting is already part of the welded steel tube "sub-frame", the batteries have been packaged for the most part but I need to weld on a few brackets to hold them. The controller needs to be mounted (either under the seat or under the batteries). After that will follow a few more mechanical things such as a chain tensioner since the Buell swing arm does not have adjusting screws at the end, some kind of 3D printed enclosure box for the main contractor and other electrical bits, and BMS if I will end up using one. Then I will start working on the wiring harness and battery connections and finally the setup up of the ZF75-7 and the Sevcon using the DVT software. Like I said the goal is summer 2019 first track day. First test ride early 2019.

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I think that's a good start for now. I hope you enjoy my build. I'm looking forward to your comments and criticisms :D . You can follow me on Instagram @ stamen.tintikov if you want. I will also post photos and videos of the build there. Stay tuned...
 
Wow, a fantastic build up!
For racing you need watercooling system, especially for longer distances.
I for example running only the 402m but for my next phase of build up I also want to run motor and controller by watercooling system.
So I have the possibility after a run to cool down the whole system faster!
 
Look forward to seeing this one come together... should be a beast.
 
Next up was some work on the front fork. The inner tubes had some slight corrosion on them that was taken care of with a Scotch-Brite pad and some WD40. :wink: Then I took apart the entire fork assembly to clean out the internals. Everything was in decent shape but it was good to do a full service and hit all the little places especially the compression and rebound adjusters. For cleaning I used brake cleaner. The o-rings are ok with a little brake cleaner exposure.

Now that the front suspension is rebuild I'm ready to mount the triple clamps, shock, and wheels in order to get a rolling chassis assembled. After that I have to start looking at the battery packaging and figure out what kind of brackets I'm going to need to weld up in order to mount them. I also want to check the ground clearance (even thought the bike won't be fully loaded) to get a rough idea of where I will mount the Sevcon. I kind of like the idea of having it low-slung underneath the batteries so that it can get some good air flow for cooling, but we'll see. I would be worried about it in a potential crash. :cry:

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Freaking awesome, thanks for sharing the renders and details. I've ridden a few Buell's and my impression is the front end can be a little twitchy on change of direction under power. I imagine you'd have a better idea. From a semantics perspective over constructed equates with under engineered not over. :D Good luck and keep us updated with your progress, I'd suggest talking to Chris and Ripperton about their lessons learned.
 
Rube said:
I've ridden a few Buell's and my impression is the front end can be a little twitchy on change of direction under power.

Yea the front end is pretty twitchy due to the short wheelbase and the small rake angle only 21 degrees!! But I plan to get a steering damper and if necessary a trail kit that basically uses offset bearing to change the rake angle and add more trial for high speed stability. Although depending on the track it could be advantageous with the original setup.
 
Small update on the progress from the last couple of days. I managed to get the entire front and rear suspension and wheels assembled in order to get the rolling chassis. No problems so far... It was a great feeling to see it all come together and roll. :D

Today I will mount the motor and attach the chain. Then I will look at an attachment solution for the batteries. Check out the pictures.

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Nice progress, the cat seems happy. Amusing/ interesting design evolution considering the original design, and now the twin spars are working with a spaceframe to holding batteries that replace a very traditional stressed member. Off topic but seeing a KTM freeride battery made me consider options for the battery as a stressed member.
Good job with the suspension rebuild, I'm sure the cat approves.
 
Hey everyone! Been busy the last couple of weeks with holidays and family visits, but I did manage to make some progress with the bike. 8) So here is the update...

After getting the rolling chassis together I went on to mount the motor. That's where the first problem arose. The mount holes in the motor didn't exactly line up with the chassis mounts. When the support frame was being welded I did have the motor mocked up to make sure the alignment of the mounting holes was OK, but it seems that there was some movement during welding. I also made a laser cut template which I used to check the the mounting afterwards.

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Yea that doesn't look so good... :eek:
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So I put my drill to good use and opened up the front mount holes. Took some time but I made it work in the end. :D Getting this frame welded up and lined up was quite a task so overall I am pleased. It could have been a lot worse.

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Since I ended up opening the two of the holes to 12 mm in dia. I had to use two washer to make sure the bolt heads had enough clamping area. The second washer was bigger for that reason.

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On the other side of the motor (left from a riders perspective) I left a gap for alignment purposes so I had to use spacers and washer to get the required length to the chassis mounts.
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Here are some more pictures of the welded support frame...

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This is the rear main mount to the original Buell frame. Its made from an outer steel tube with a polyurethane bushing inside and then another steel tube on the inside of the bushing for the bolt to go through. Then it is supported by those two welded plates which are 1/4" thick or 6.35 mm for my metric people. :wink:
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The swing arm mounts can be seen below. The pivot shaft threads into the far end and is clamped at the front.
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The threaded end below. Basically I took a nut and welded it to the machined mount on the back side.
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Clearance between the swing arm mounts and the back of the motor is about 10 mm.
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And some more pictures of the rolling chassis with the tail mounted...
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Ok so after getting the motor mounting situation resolved I attached the chain to check out the alignment and clearances.

24k gold :lol:
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I had to use some zip ties to hold the chain together. I will need to design some kind of chain tensioner/roller system right around where my fingers are in the picture below. (Note that in this picture the bike is upside down on the floor). Another thing I hadn't realized from the beginning when I designed the support frame was how far forward from the swing arm pivot the motor sprocket ended up. This will increase the lever arm to the pivot and thus the torque from the chain pull force. I believe that will cause more squat at the rear end. :? There is also the distance of the chain to the swingarm pivot and the angle to the swing arm. I'll have to see how bad it is and figure out how to solve it if it's a problem. I think there are ways around it if is that bad including suspension tuning, chain tensioner geometry, and maybe a secondary drive sprocket. Also the chain is not cut to the correct length yet...
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In the next two pictures you can see that the lateral alignment of the motor and wheel sprocket is pretty dam good and the chain looks straight. I'm really happy that worked out. Again I did mock this up when the frame was getting welded together. :wink:
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In the next two picture I was checking the clearance to the foot peg bracket. In the lateral direction it is a little tight to the inside of the bracket. I will either machine out some material or make completely new custom brackets with foot peg position adjustment holes. (Note here the bike is on the floor)
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Next is the battery and controller situation....
 
Thanks for bumping this one, I hadn't seen it before. Wow!
That may be the most challenging donor bike candidate I've ever seen, lol. I didn't know the swingarm was hung from the engine on the XB, that's interesting.
You made some unbelievable lemonade here though. That trellis frame is a work of art. I'd love to hear more details on the process of fitting and welding the tubing. Did you make a jig? Was it TIG'ed? How did you settle on 1" DOM? My gut says 1" is overkill, but my gut isn't calibrated for swingarm mounts ...
Looks like fitting the leaf modules might be a challenge. What's the strategy there?
Really great job, I hope to hear more about it.
 
Great job on your build!
 
Beautiful work, I'm looking forward to the finished product. If you don't already have the Leaf cell modules, it's my understanding that the newer ones have a much higher C-rate.
 
spinningmagnets said:
Beautiful work, I'm looking forward to the finished product. If you don't already have the Leaf cell modules, it's my understanding that the newer ones have a much higher C-rate.

Do you happen to have a source? I've been looking for 2017/2018 modules for a few weeks with no luck.
 
The link below is the most well-known first stop. You might get lucky from EBAY, or some other source, but that business is frequently the supplier of lightly used cells.

http://hybridautocenter.com/HAC4/in...ashop&view=category&layout=listing&Itemid=195

"Salvaged EV cells index, Leaf, Volt, Tesla, etc"
https://endless-sphere.com/forums/viewtopic.php?f=14&t=89680

Since the performance of the Leaf was not dramatically improved, the change to a higher C-rate of cell just means that they would run cooler under normal loads. This makes sense because the earliest Leafs suffered from early degradation of the pack under warranty, because it was only air-cooled. Places like Arizona in the summertime had air-temps of 115F, even before applying a load to the battery. The newer cells are sometimes referred to as the "Lizard" cells.
 
How did I miss this thread? Beautiful work!
I will follow keenly with great interest :)
 
Hey guys. Sorry it's been a month or two since my last post, but nonetheless I've been working on the Buell. I charged all 14 Leaf modules up to 7.6V so that I can wire-up the entire electric drive train on a bench and test everything before it goes into the bike. So to do that I need to order a couple of components still (contactors, DC:DC, etc). I finished my wiring diagram and I would like to get your feedback on it before I pull the trigger on ordering things. :thumb:

Also I'm wondering if someone can tell me if I need to have a forward/reverse, FS1, and seat switch wired up on the Sevcon in order for it to work. I've been reading the manual and it's not clear to me because in section 2-4 of the Gen4 manual it states the following. That text makes me think that I don't need the switches.

Here's the diagram.
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I'll share some pictures of the controller and battery mounting as soon as my brackets get made. Hopefully in the next 2-3 weeks.
 
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