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MattRobertson

Has anyone opened up their motor?

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Has anyone broken into the insides of their Bafang motors?

As part of my assembly I will be removing the wheels and adding Tuffy, potentially beefing up the rim strips and changing to thicker presta-valved tubes.  While I am down there I may as well repack the bearings with a known weatherproof grease (Mobilgrease 28 - magical, tenacious aviation stuff that is safe for plastics, among other things).

If I am going to that level of trouble, why not crack open the motor?  I've already seen via blogs and threads at electricbike.com that Bafang uses white lithium grease that, by its nature, is rather thin and tends to get thrown around and off the gears, onto the inner wall of the motor where it is ineffective.  It also hardens up after a couple years.  

I was thinking that cleaning out that motor of that grease and upgrading same could go a long way towards preserving the gears over time.

Edited by MoneyPit
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This is a stock motor on the left vs a 750w motor on the right. Some people have successfully swapped the 750 with the 350. You can apply grease to the gears. All the bearings are sealed.

350 vs 750.jpg

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What are the performance benefits of dropping a 750W motor into the 350W hub? Twice the speed, but half the range? (Assuming you kept the stock battery?)

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Hey Diabolus,  I'll have to acquiesce to Houshmand's Conversion. This is his performance testing but for all of the conversion details read farther up the thread. Not With Stock Battery. 

 

 

Edited by Tabletteer

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16 hours ago, DIABOLUS said:

What are the performance benefits of dropping a 750W motor into the 350W hub? Twice the speed, but half the range? (Assuming you kept the stock battery?)

The 750w motor is meant for 48v. It might work with 36v, but probably not that well.

The 750 motor doesn't offer any faster top speed over the 350, but is has more than twice the torque. Where the 350 strains to sprint across a busy street, the 750 rockets across. The 750 accelerates up hills that leave the 350 gasping for air. Even though there's no additional top speed, the 750 gets up to it a lot faster, and so is a lot more enjoyable to ride.

Riding at cruising speeds there's not much difference in power consumption. Both motors cruise along using about the watts, at the same speed. The difference is when using the extra acceleration available from the 750.

Having 7 speed pedal gearing is also a big attraction for the 750. It's gives you the ability to have both lower, and higher gearing than stock. With the right choice of ratios you can pedal up any hill no matter how steep, but never out ride the gearing at high speeds.

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biknut you paired the 750 with the 35 watt velomobileshop controller, right?  Thats the route I am going and will follow it up with a Luna front Bafang 750 motor as Houshmand Moarefi did.  Hopefully with some better routing than he showed us in what was pretty early in his build.  We never really got to see how he refined it over time.

My 750 arrives Thursday, but I don't trust the wheel long term on a daily commuter so looking to get a new one built.

 

Edited by MattRobertson

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I am riding daily on rough city streets, oftentimes after dark or before dawn since I'm going to work so I don't always see the best path.  I am typically running now around 24-28mph.  With my two toolkits and work clothes/shoes and now charger I bet I have added 12-15 lbs to the rear in the saddlebags, and I am 250 on top of that - hopefully slimming down as I get back into the riding groove.  The mockup of the battery and 35a controller that I have on the front wheel adds more weight.  Since January when I got the bike I have put on almost 400 miles as of today.  Rain days have cut out a lot of ride time.

I just don't want to be the guy who finds the outer limits of these rims and I might be the kind of rider who's going to find out.  I know you have been running yours well-hotrodded for quite a while, just fine.  And you aren't alone.  Despite all the Sondors naysaying, the Chinese know how to build durable daily drivers.  But with all the above I'll feel better having spec'd out known parts that are stronger than that norm. 

I'm doing Origin8 dual wall 80mm rims (as I understand it these are the Weinmann's Luna uses but stamped with the Origin8 logo), DT Champion spokes.  Built by my LBS - took a LOT to find one in the Fresno CA area as I had the usual ebike prejudice to deal with at many shops.  

Hopefully the rims will finally arrive this week.

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Speaking to the original post in the thread, Its starting to get louder, especially off the line where I sometimes get vibration thru the chainstays.  Even though its getting replaced soon, I may open it up and check it out at the least.

Edited by MattRobertson

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The noise may be caused by magnets that have come unglued inside the motor. There was a guy on one of the Sondors FB support groups who was helping people by regluing the magnets with a stronger epoxy. Though the magnets come loose, they don't go very far because there isn't much room for them to move and they are still doing their job to some degree. They could break if dislodged. My fattie is a little loud, but I will wait since I'm hoping to do the 750w exchange.

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The Hub is on the 750 Watt Bafang 8Fun Geared "Hub" Motor.

if you mean the gears cluster,, there are many HG Shimano of various ratios and tooth counts, avalable online or any bike shop...you'll want to consider what mountains you'll climb or how flat it is where you ride , to decide. 

Edited by Tabletteer

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@WillA wrote: "The noise may be caused by magnets that have come unglued inside the motor. There was a guy on one of the Sondors FB support groups who was helping people by regluing the magnets with a stronger epoxy. Though the magnets come loose, they don't go very far because there isn't much room for them to move and they are still doing their job to some degree. They could break if dislodged. My fattie is a little loud, but I will wait since I'm hoping to do the 750w exchange"

That would be a very seldom reported malady, mostly the noise is from nylon gear wear or missing teeth. Wanna accelerate that wear, hit the throttle with the rear wheel captive and you'll hear the chatter of the pinion and stationary planetary gears slipping/grinding/chatter. There is the possibility of a bad or worn sealed motor bearing, again very rare and not reported to the forum so far. .

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Edited by Tabletteer

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On 2/28/2017 at 3:18 PM, Tabletteer said:

The Hub is on the 750 Watt Bafang 8Fun Geared Hub Motor.

if you mean the gear cassette, there are many HG Shimano of various ratios and tooth counts, avalable online or any bike shop...you'll want to consider what mountains you'll climb or how flat it is where you ride , to decide. 

 

My question is what type of gears are needed? A thread on freewheel hub or a cassette that attaches to splines.   I know what gear ratios I want, I am just not sure what type of gears to get. Are HG Shimanos all threaded? Thanks.

 

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Start here: https://www.amazon.com/gp/product/B001IORDH0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Sorry, yes Freewheel not Cassette. As far as I know all HGs are Threaded Hyper Glide. 

"A large part of the success of the Shimano company is based on the cassette freehub, which has become nearly universal on decent quality bicyles. Up through the mid 1980s, most bikes used traditional thread-on freewheels and matching hubs.
The success of the cassette Freehub is partly a technical success and partly a marketing success. Freehubs are superior to the older thread on design in many ways:
They give much better support to the axle, causing bent/broken axles to be almost non-existent on modern bikes.
They are much easier to work on, because there are no parts that get screwed tight by the rider's pedaling effort.
They provide greater flexibility in gearing choice, and are easier to create custom gear sets with, since all of the sprockets use the same spline pattern.
Replacement cassettes are generally cheaper than complete freewheels of similar quality.
Acceptance of cassette Freehubs was gradual throughout the '80s, and many cyclists/manufacturers were reluctant to move to the new system for fear that it might not catch on, and that the parts would become difficult to replace over time. (Exactly the opposite is what has turned out to be the case!)
When Shimano started moving to 7-speed systems, in the mid 1980s, they used their marketing clout to push things along. They did this by making 7-speed an option only supported with their Freehubs, and not making 7-speed freewheels (except for a couple of expensive, high-end road models, Dura-Ace and Santé.) Thus, if you wanted 7-speed Shimano SIS shifting (and everybody did!) you had to buy into the cassette Freehub system.
Almost overnight, Freehubs became the norm for good-quality bikes, and thread-on freewheels were relegated to only the cheapest low-end bikes.
Shimano continued to make thread-on freewheels for the lower end market, in 5- and 6-speed versions. After a few years, once the cassette Freehub was well established for higher end bikes, they even started making 7-speed freewheels".

 

image.jpeg.2779221537dbd829b7385c27a70c0caf.jpeg

 

Reddy

Edited by Tabletteer

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