Electric Motorcycle Conversion Questions

I am planning a conversion and I found a motor at a OK price. I just don’t know if it is up for the job. I am hoping someone here is familiar with it. It is a Advanced DC Model K99-4007 series wound 6 hp @ 48v 2400rpm 120 amps. I would like to run it @ 72-84v.

It will be going on a large cycle (1980 Honda CB750c).
So far the plan is:
[B]Batteries[/B] 6-7 B&B EB50-12’s
[B]Controller[/B] ? Kelly 84v maybe not sure yet.
[B]Drive ratio[/B] Ideas anyone ?

The motorcycle has a GVWR of 1010 lbs. A dry weight of 526 lbs. The rear tire is apx. 24 inches in diameter. Allowing ~300 lbs for motor and batteries the rolling weight with me and what I will need to carry will be about 900 lbs.

I would like to get a range of 12+ miles with no more than a 60% DOD.
Top speed 50-60MPH
Avg. Speed 35MPH
Acceleration 0-60 ~7 sec.
To get the range I will trade top speed and/or acceleration. The 12 mile range is a must!

If anyone has any insight they can offer please do. I am not locked into anything except the motorcycle and hopefully the motor:). I know the motor is good for 72v and I believe it may be good to 96v. I have to research more and I have looked everywhere I can think of.


Hey Greg,

I think you may have already seen what I have been doing.

If you haven’t yet, and for anyone else, here’s the little web page I put together for my project.



Greg, That motor is perfect for a road going Ev motorcycle conversion. Most people use the Etek for such conversions, they are lighter than the motor you have, but very similar ratings. The Etek is only designed for 48volts, however. Some have been run to 72v, but this is pushing things. The motor you have is rather overbuilt, and could see much higher voltage than it is rated for (continuously), but for 72 or 96 volts you should be fine. Cooling is the primary thing, keep it in the airstream, and you’ll be stylin. Go forth, Eric

I bought 2 K99’s, and Jim Husted (HiTorque) is going to press some new shafts into them, and put better bearings in.

they’re exactly the same electrically as the K91, another popular ADC motor. Mechanically, the shaft is different, and there is no side mounting plate, its face mounted.

here’s the datasheet on the two:



Even though the K99 says 48V, its really 48-96.

I’ve got 72-96V torque curves if you need them as well.

here’s my project:


Thanks to all for the info.

Why have the shafts and bearings changed?
Well the shaft I can see but is their something wrong with the bearings?

And thanks for the datasheets

I would like to see 72-96V torque curves also if it is not too much trouble.
Thanks for the link to your blog. Now I have more reading to do.

I have been watching your progress. It pretty much pushed me over the edge…

Has anyone used a Kelly controller? I would like to hear from someone that has tried the 84v model. It may be possible to put 7 batteries in the frame. If not I will probably use an Alltrax at 72v.

I have not had time to work on it the last week or so. I hope to get back to it after I finish moving and the holidays are over.


here’s the datasheet. Right click and save, or its a PITA to view.


The reason to put bearings in is 1) I don’t know how long its been surplus, so if its rusted, it can fail early 2) Jim said the bearings are worth upgrading, and now is a good time to do it. ADC doesn’t put in high quality bearings. There’s also good reasons to listen to Jim husted, His motors are in Killacycle and White Zombie… be rebuilds them for a living. Its cheap and not hard to do with the motor apart already.

I want to put in a new shaft and bearings ONLY if I can’t get this motor to work as is. I’ll inspect it before powering up. I’m going to see what I can do with it, and get it mounted first. I’ll likely chop off that long a** shaft.

BTW, you were the one that caused me to look up a datasheet for this motor (when I searched for it, I found the link to buy it at Surplus Center). I did a ton of research with ADC and Jim and came to the conclusion, it was a decent motor. Plus, a couple other guys used them on Cycles, and had good luck. So wish me luck. If you wait until next week, I’ll let you know how it looks.

Thanks for the datasheet.

Have you looked into a way to support the tail of the motor?
At ~60 lbs. it is a lot of weight to go bouncing down the road depending on the face mount only.
There is a clamp type mount listed at evparts but i don’t think I will be able to fit it in my bike without a lot difficulty.

I am going to use the motor as is to start with and see how it works out. I am going to cut the long shaft though.

I hooked mine up to 12 volts and it did not make any noise or release any smoke.:smiley:


yeah, I figure I’ll have to support it some way… we’ll see. Jim said he might put some mounting holes in the case for me to mount a bracket… so that would definately help. These motors are made to be mounted like that, and this one was for a forlift, so its made to be bumped a little. Just make sure the mount is heafty.

Keep us posted.

Do you have some pictures? PM me and maybe send me a few via email.

I took some pictures and posted them here.

If there is any other view you would like let me know.
It may take a day or so to get them as I am moving.
But I can take a break for the important things.:smiley:

Is does seem likely that ADC would have a bracket if one was needed. But I don’t like to rely on common sense.:wink:

i’ll be darned, I got my motors in today… tested one and DANG… on 12V its torqy… bout made my GF run off in fright while she was holding it down.

Not a bad little motor, alot heavier than I figured they’d be, but they’re still 56lbs.

Does your brush cover fit? One of mine doesn’t fit.

The cover fits. It does look like it is made to fit several models though. There are a couple of extra notches.

Part of the cover was bent into the brush conductor in one place. It may have tenderized during shipment. It was well packaged so it could have been done before shipping.