nostroke

Wow. I don't see how they can do that. IF I take mine to market, which I am still not so sure of doing, it was going to be closer to $10k. I rode mine at Dallesport COTA event this weekend. My first trials event ever so I entered novice at the request of the marshal (yeah, I know, trail riding). But I got to see how the events are structured and had a blast. I did a few intermediate sections and the bike performed really well. Plenty of power for everything in that class, no problem. My wife took a bunch of nice family photos and videos (I let my son ride the first beater prototype), but nothing worth a posting really.

Pretty much the same. This has a more developed battery quick swapping system. Also, 1.2 kWh of capacity. I am using a 500 amp peak controller but in practice it rarely pulls more than 200 amps, even on steep inclines or wheelies. Weighs just 60 kilos (134#). The biggest change really is the chassis, which now has a 4 bar linkage on the rear Olle shock and awesome formula forks and brakes. I'm planing on entering an event this weekend and see how it (and me) holds up.

Just finished a new bike.This is the dash 3 version. New and improved! I got forks and brakes from Formula, wheels from FABA and made pretty much everything else.

Have you looked at the Monty trials rims and tires? I built a few electric bikes for small kids about 10 years ago using them and they are awesome. If you use 24" bicycle rims there are a few wide 3.0" downhill tires like Nokian Gazzalodi. But nothing works as well as a gummy 4.00 x 18 m/c tire, although the scale is a bit out of whack on a smaller rig. Regarding the throttle pot...if you can find a 1" travel slide pot with an audio taper and cable operate it, it has a great feel but its not very durable as most of the pots are crappy (at Radio Shack).

Well, I built up the cable pot system using a 45 degree pot from a Curtis potbox and the Magura 313 Trials Throttle and designed it for 32mm of cable pull, almost a half twist to full throttle. I like it. You have to be more aggressive with it but control is much better. I mounted it on the fork, behind the front number plate, so the cable doesn't have to contend with any steering movement.

I have a funny thing going on with my GasGas conversion..it has a low speed misfire! It acts like a dirty carb or half fouled plug. I am pretty sure its just a dirty potentiometer wiper in the Magura twist throttle, but it adds an element of gas realism that I think is cool, in a twisted sort of way. Its not a distraction because its very minor and just at one distinct throttle position. Anyways, I have had a few people complain of wrist issues using this throttle so I am curious to see if the cable pull pot setup improves things. Because I have no E-Clutch (anti-throttle, whatever), the throttle is crucial to good bike control. The Magura trhottle, with no cable (the pot is internal, in the twist grip assy), its probably too smooth. In other words, there is no friction feedback which I think may actually be a unintended but useful fault in a cable system. That smoothness, combined with a very sensitive quick throttle (about 45 degrees of rotation) can be very fatiguing, requiring too much focus on the throttle.

I am building a new electric trials bike here at my shop and am interested in how that throttle/ anti-throttle clutch setup works for you. On my GasGas conversion here, I am using a Magura twist throttle and its making me sore! Its only a 45 to 60 degree turn and, while it offers great power delivery, its just too hyper. So I have ordered a Magura 120 degree and a Domino 90 degree that I will use to spin a remote mounted pot with a cable. (BTW I have NO clutch / anti throttle set up)

With regard to the clutch, I've all of sudden gotten buried with actual paying work here at my shop and have not had time to do much. But I did come across this accelerometer in my box of old project stuff and have to ask what you think about incorporating a "wheely mode" into this circuit? http://www.meas-spec...nloads/3028.pdf (I can't seem to make the link work in this post.) I recently had to replace the kill switch and found one with a start button, which got me thinking how cool it would be to be able to hold down the start button and have the bike pop up and modulate the throttle at some angle determined by the orientation of the sensor . My thinking is that we could use say the positive or neg mV output to drive a transistor that would control the throttle. I had originally thought maybe a full on 4 quadrant servo would be needed for this, like on the Segway but I'm inclined to think it could work with just a single direction speed control (and careful rear brake use while dialing it in). The one I have here is the 2G version, which seems like what you would need.

I finally clamped a good current meter on my battery lead, pinned it and I saw close to 400 amps ( which is the setting on my Alltrax). I will look around for a higher current shunt. I found yours no problem at Newark. I HAD one lying around..grrr. The one I had was about 1" OD and you would feed your #6 cable thru it instead of the Allegro with solder pins. What do you think? I expect some scaling would be in order most likely (if I can find mine).

You really should have photoshopped the gauges on the dyno. So is that IC a comparator or something of that ilk? The board looks really simple and elegantly analog. If you send the schematic, I will build it no doubt and have it up and running in a few days. One of my issues with twist throttle only control is that it is hell on the right wrist. You have to hold a lot of tension there to maintain control of both the handlebar and the twist grip position, not to mention if you need the front brake. No different than the gas bike really, in that regard. Today I swapped out the stock AJP front master cylinder with a Formula unit off a OEM KTM 80,. with nicer ergo than the AJP, but It has a tiny piston and is nearly impossible to bleed. I think this should help the wrist problem. I hope to have it bled properly in a few years, I'll get back to you then.

Thanks much! I'll warm up the Weller! Ive actually got a few Hall current sensors here but doubt I can find them. We had a fire here about a year ago and I tossed a bunch of electronics stuff that was sooty. And yes, it WAS caused by Lithiums. Store with caution! I think the fire was caused by my own lack of concern to some extent...I had a 24S, 100V 10 AH pack that I knew was leaking and it was in an aluminum sheet metal case. I had forgotten about it for a month or so and one night it decided it had enough. It was not charging or used for several months prior to the ignition, just sitting, leaking and corroding the case. Once bit twice shy. Now I have a flammable storage locker for cells and store bikes where they couldn't ignite anything else IF they went into meltdown mode.

That would be great. I can likely figure it all out. I'm not a EE but I did once make a fuel injection system for a Honda Hawk from a 555 timer set up as a one-shot. (It sucked but did work). I take it this circuit deals with just the throttle control voltage? No other inputs? Hope not because there aint any more inputs! Well, there is a 1/2 speed enabled by B+ but that's it.

So last night I rigged up a clutch pot, using a 5k linear pot with a 12mm stroke, the same as the master cyl piston travel. I think if I put the pot in series with the throttle pot (2-wire), with the low resistance position in the 'clutch out', it would work as normal. But when I pull the clutch in, it will effectively reduce the throttle signal. Due to my dyslexia, I probably have this backwards, so I'll be sure to remove the drive chain while futzing around. It should work similar to your more elaborate scheme, which I cannot do with this controller.

gwhy-To be clear, with your e-clutch, I take it that the twist throttle, when the clutch is depressed, simply sets the peak available power. The clutch lever, as it is released, modulates power within the limits set by the twist grip? The clutch sort of IS the throttle in this case? The more I ride with just a twist grip, I can see a need for a more precise control, which I believe the E clutch would provide, once I got used to it. Another approach might be a non-rotating grip on the right and a index finger trigger on the left side. Seems like this would free up the right hand for better front brake wrangling. I confess, I have as much fun modifying stuff as I do riding. Go figure. Hey how about a foot operated mousetrap suicide clutch!

I guess the next feature we need to see on motor controllers is the ability to play .WAV files. I wonder if I could copyright the pop pop pop of a properly muffled two-stroke?

Damn. Can't wait to see what he gets when he's 5! When I was a kid, I had to borrow our lawn mower motor for my mini bike. Anchored it with plumber's tape. Good to go. So when are you ordering the carbon Marchenisi wheels?

I once took a piezo buzzer and connected it in parallel with two 2 motor leads (brush motor), so it would increase the frequency based on the voltage supplied to the motor. It was very cheap and simple. And annoying! Your 3 phase brushless motors have a lot more levels of control, like speed vs torque, that I'm sure let the engineer tailor things way beyond what I can with my garden variety golf car controller, which acts like a current controller. I would love to try one. Maybe in a few years there will be an electric class in comps, or at least a forum dedicated to full sized electrics. I think I may be suffering from an inferiority complex due to having to post in the kiddie bike forum!

I guess I am sort of obsessed with the idea that at some point a pro rider will whine that electrics can't do the big launches. The design I'm working on is a sort of inside out version of a typical gas bike clutch. So instead of the primary gears being the input and the mainshaft (inner hub) being the output of the clutch, this design would use the motor shaft keyed, splined, whatever, to the inner clutch hub. Then the output would be a countershaft sprocket attached to the outer basket. The crank assy (w/ flywheel) on most gas trials bikes is around 20 lbs, the same weight approximately as the rotor on most electric motors of this scale. I think with the added inertial moment of the pancake motors relatively large OD, you could get more flywheel driven launch than a gas bike. In fact, I think that maybe the electric motor could be even lighter, maybe just 10 to 15 pounds of motor total weight with more inertia from added RPMs if needed. Anyways, this is just kind of a dream of mine, that I could make an electric that out-performs a gas trials bike and still weighs less. I think the technology is here today to do this. All that said, I really like not having a clutch to fiddle with. At my stage of riding, I'm still working on my basic balance skills, not falling over at a standstill!

My concern with doing the whoopee launch electronically is based purely on theory and not experience, so I'm kinda talking out my butt here. But I would think that a 20 pound mass spinning at 5 to 6k rpm would dump a lot more energy than most of today's batteries or electronics would deliver. My gut says that if you could translate maybe 800 to 1200 amps into torque efficiently with your electronics, it could equal the flywheel effects' massive outburst. But I doubt that a normal human could modulate that, even if you could deliver those currents efficiently. Again, this is theory, not observation, although I did ride Scorpa's earliest prototype several years ago with a very early potentiometer set up on the clutch. I expect its been electronically refined a lot since then, but physics is physics. So I still say a flywheel will out-launch most electronics, In theory. I've heard many call a BMS a battery murdering system, heh. But like everything they are always getting better.

I don't know much about the EM motor / controller. But the settings on my rig, which uses an Alltrax controller, are way simple. Because its a permanent magnet motor, there isn't much to tune. Only the throttle ramp which I do my best to fully disable. I want instant response. The touchier, the better, A lot of the newer electrics use brushless motors, which I have used in road going vehicles. Brushless motors are somewhat more efficient in terms of energy consumption. But typically, the motors and controllers are on the heavy side. And further, the last thing I want is an electrical engineer deciding how responsive I should have my throttle. I expect that is why the Scorpa and GAS GAS conversion use that (what I consider) hokey method of using a clutch operated potentiometer to make the bike more gas-like. I can see a need for a clutch when you need massive honks of torque, but it would need a real friction clutch to really do the deed, IMHO. I have modelled a friction clutch that would fit onto the motor shaft directly with no jackshafts or secondary reduction required, but have yet to build it. I am waiting until my riding skills are good enough to use that much launch! I don't use an on board BMS. I use RC car stuff for monitoring and balancing the cells, but they rarely need it. And as for over-discharge issues, I just quit riding when the power fades, which is usually a bit above the danger zone. I never pull the cell voltage below about 3.7 volts, which is very safe.

gwhy-sounds like you may have cells similar to mine, which are not really RC car cells. These are 10 AH lithium cobalt pouches. I made up two mini packs of 10S (~42V end of charge). I parallel these when I plug them onto the bike's harness. I was originally going to use 3 of these mini's in parallel for a 30 AH system, but these cobalt cells deliver the full pop, peaks of 20C (400 amps total). The down side is that these are also the cells that grounded the Boeing Dreamliner I think, ie, they can catch fire and you have to keep that in mind when storing the bike.Why they (Boeing) would chose these hot rod cells for an airplane is beyond me, but they rock for performance.

I usually ride the bike for about 1 hour before I can detect any power loss, which means its done. I could add more battery capacity but I really like the light weight and my old body is pretty hammered after 1 hour. anyways. I've built a lot of electrics, cars, bikes, trucks, etc and the first question is ALWAYS how long will it run. And there is never an easy answer because,just like a gas engine, it depends a lot on how hard you ride. But for me anyways, the run time is more than adequate, but I don't compete. There are other issues that would need to be addressed if one wanted to run with the big dogs. But as you all know, there is a big gap between just riding for fun in your back yard VS a pro event. For instance, I did not concern myself with water issues. The motor is quite exposed which helps with air cooling but would certainly have issues in competition. When I look at the designs done by Scorpa and GAS GAS, they have clearly done a better job of making their electrics water (and idiot) proof. I'll try to get a video up showing its performance. I think its pretty compelling using electrics for practice bikes. It will wheely up any hill very easily. Before I converted it, I rode it for a day and was reminded how incredibly hard it is to modulate the clutch throttle and brakes simultaneously. The electric is very easy in this regard.

I bought a used Gas Gas TXT 200 and converted to electric. I used a Briggs and Stratton E tek motor direct drive (11 / 60) gearing with a 428 chain / sprocket that I made. I use a battery pack made from RC car LiPo cells, 42 volts, 20 amphour. Am loving it, ride it every day in a residential area with no complaints. The bike weighs 145 pounds and makes just under 20 HP, lots of torque.