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[ed5000]

I have a 2010 DS with an Agni motor that became another victim of motor burn-out where the brushes burn and break up.  The damage also extends to the plastic brush plate and very slightly to the commutator.  Zero is sending me a new motor (for which I'm grateful) but I have to wait a few weeks to get it.

In the meantime, I was able to use the brush plate and four of the motor brushes from the first burned up motor that came with the bike (from the original owner) and substitutle them in my motor to get the bike running again.  When I first test drove the bike I was driving like a total grandma taking it slow and easy.  No hard take offs and no freeways.  Just local in town driving.  Still, I was getting a burning electrical smell from the motor but not as strong as my original burnout.  I kept driving it easy and after a week the electrical smells went away as the brushes were breaking in. 

Now, nearly a month later, I can drive the freeways at full speed, commute to work, etc.  The motor works so well I can honestly say the only difference I can tell of the motor is a slightly irregular motor brush sound because of the unevenness of the commutator (damaged from overheating).  I should probably have the commutator machined.  I still need the new motor because two of the brush openings in the brush plate are enlarged resulting in wobbly brushes and one brush was less than one inch long where the rest (8 total) were closer to 1- 1/4 inches long. 

I guess what I'm getting at is there is a reason for the slower accelleration of the Agni equiped bikes.  A little less accelleration means a cooler motor which is a good thing.  Sure blasting off from the light once or twice is fine (and a lot of fun) but doing it too many times seems to accumilate heat in the motor and thus may cause failure.  Other ways to overheat a motor (but maybe a little less likely) are going up long up hill roads at higher speeds and the other, very warm days.  Add all three of these together, which is exactly what I did, and you have a perfect storm.  Ideal conditions for an Agni flameout. 

I say take it easy, these are great bikes.  Right now I'm glad to have mine back. 

[manlytom]

We just went on a ride (2010DS and 2011s) with twisties and some hills. Noticed that my fan was running on the 2011 whereas not on the 2010. Now i got a bit more miles on mine and cleaned up the motor once - and one can hear the brushes quite well.
I ride a lot in traffic and usually take off normally - means twist and go. Found that even when the fan runs the motor is just warm to touch. So i am suprised that yours keeps burning out. Unless the temp sensors is not sensitive or so on your 2010?

[ed5000]

We just went on a ride (2010DS and 2011s) with twisties and some hills. Noticed that my fan was running on the 2011 whereas not on the 2010. Now i got a bit more miles on mine and cleaned up the motor once - and one can hear the brushes quite well.
I ride a lot in traffic and usually take off normally - means twist and go. Found that even when the fan runs the motor is just warm to touch. So i am suprised that yours keeps burning out. Unless the temp sensors is not sensitive or so on your 2010?

You could be right about the temp sensitivity.  I usually go a mile or two before the fan ever comes on.  As for motor burnouts, this is technically my first burnout although the previous owner also had one before I bought the bike.  I plan on taking it easier from now on.

The good news is Zero called me to say they have my motor in.   

[manlytom]

still a bit surprising. I ride it, have fun, turn the throttle - yes have some glitches but motor and brushes look reasonable well. I am more chasing some details/intermittent wrong.
let us know how u go with new motor. I plan to swap to new motor as well and see if I get a difference.

[paul]

When I built an e-bike with an Agni motor that got pushed to its ragged edge with an Alltrax 650A controller that ran a few tenths of a volt below its overvoltage cutout limit, I pedaled the bike around the block a few times with the motor engaged to seat the brushes to the rotor before ever hooking up the battery. 

Despite being abused beyond belief, that motor never even had the electrical stink going on, so brush problems didn't seem like they'd ever occur.

Taking it real easy for the first bit of runtime on the motor is essential to any hope of a reliable life IMO. 

Zero always did a burn-in period for Agnis on the bench before installing them, but I think that the less power (if any) that one pushes during the first few few minutes of spinning a motor on fresh brushes, the less likely there'll ever be issues with them...

[trikester]

It is important to seat brushes before using a motor under load and speed. On small motors a common practice was to un the motor without load for 24 hours at a very low rpm voltage. However, the brushed motors used on these bikes are series wound so speed keeps increasing as load is reduced (the brushless AC motors don't do this). The rpm could go very high (dangerously) even at low drive levels if some load isn't provided. Driving a fan blade would work because load increases as rpm increases (like a bicycle trainer machine) and would limit rpm.

Trikester

[ed5000]

I had very good luck with seating the brushes.  I just drove the bike around town as easy as I could taking the slowest residential streets I could find.  That did the trick.  I do have one hill I have to climb to get to my house and that was where I think the burning smell was coming from initially during the break-in.   After that, the motor just got better and better with only a funny sound from the uneven commutator.

Zero has my bike now at one of their zero dealers.  They wanted to install the new motor for me which was nice of them.  I'm very appreciative of that  but while at the dealer I looked at some of new zeros for sale.  I test drove a 2011 S and man, I was surprised to see quite a number of improvements over 2010.  I thought '10 and '11 were pretty much the same bike but no, Zero was busy back then too.  The '11 has larger brakes, slightly larger battery, newer bodywork with a quieter ride, more indicator lights on the speedo, and, of course, that super quiet belt drive.  I wanted to take it home!  On the other hand, I should try a '12 (test drove one last January) or just wait for the 2013s to come out.  Hmmmm.

[dkw12002]

I traded my 2011 S in while it was in the shop, but apparently it was a burned out motor too. While I regularly rode the bike at WOT on the interstate for an exit or two and got the motor hot enough with the fan staying on for 10 min or so after stopping, when it actually burned out (if that is what happened), I had just left Subway after a 35 min. lunch. It was 86 degrees. I went 50 yards to a stop sign and as I accelerated away, the motor hesitated once, caught, hesitated again, groaned and stopped....dead. 3500 miles. Seems to me like this is a cumulative problem and not really an overheating problem per se. I didn't feel the motor when it died, but no way could it have even been warm in 100 yards. There was no hint of rough running, abnormal brush sounds, hesitations, or any other problem before it died. I'm never going to Subway again though.

[ed5000]

Sorry to hear that dkw.  I'm convinced the warmer temperatures are hard on these Agni motors.  Last week in the Bay Area here we had a day with 91 degree temps.  On that day I drove my zero with my cobbled together motor and measured the motor's outside surface temps and I got 150 degrees where normally I don't see much over 120.  So on these days I'm just going to take it easy.  The rest of the time I can race around more.

[manlytom]

Still interestng that some of us have heat problems with the agni. The older MX models all use the Agni and accellarate very fast. They are ridden in MX races and seem to work well. Ok some people have improved the motor (picoamps.de) or rather fixed it up as original from manufacturer is not highest quality. I saw a guy mounting a PC fan just behind the Agni amd having running simply all the time on an MX.

[ed5000]

A little update here...

My 2010 DS is still in the repair shop for a motor change out and I decided to go out there last Saturday to have a look.  The bike is still in the shop because they were having problems with the main board.  The good news is Zero is sending out a new board but that means I'll have to wait a little longer.  I sure miss the bike.  The weather has been good here except for a couple rainy days.  I'm impressed with Zero's level of service on this.  So far they haven't tried to cut any corners here.

While there at the bike shop, I looked at that 2011 S again.  It was sure tempting.  It was on sale for a good price and if I had the $ I would have bought it.

In the meantime I dusted off my old electric motorcyle, actually an electric bicycle.  I haven't driven it since last March when I bought my Zero.  This bike will only do 30 mph but it's still a lot of fun.  I've driven it a bunch of times to work 16 miles away.

[Richard230]

You wouldn't get that kind of service from BMW.  They would tell you that "they all do that" or it is a "wear item" or it is your fault and just go to the sales showroom and buy a new bike - you shouldn't really have kept that thing for two years, anyway.   

[dahlheim]

You wouldn't get that kind of service from BMW.  They would tell you that "they all do that" or it is a "wear item" or it is your fault and just go to the sales showroom and buy a new bike - you shouldn't really have kept that thing for two years, anyway.   

all common responses from major manufacturers.  a major reason why i do my repairs myself.

i hope Zero keeps to its guns and doesn't sell to the major manufacturers when they come a knockin', which they will...

[dkw12002]

+1 on the e-bike ed5000. If you run out of battery on that, you just pedal it home.

[ed5000]

+1 on the e-bike ed5000. If you run out of battery on that, you just pedal it home.

Thanks dkw,  I did have to pedal home once.  A wire connection came loose and I didn't find it right away so I just pedaled home.  It took me 10 minutes instead of 4 or 5 minutes but I was happy to get home.

I should mention did have a near motorcycle version of this bike.  I have a matching front hub motor and a second controller that's progammable and I was running it at 80 volts.   It was a demon bike.  It would snap your head back and pop wheelies.  It was much faster than my 2010 DS although I was afraid to take it over 50 mph without any real suspension or disk brakes.  The fun part was I was able to commute to work 16 miles away on almost the same wh/mile so I didn't need a larger battery pack because I kept it under 30 mph the whole way (unless I was chanllenged) .  I could tell some stories but this isn't a bicycle forum.