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'68 Dnepnr motorcycle with sidecar

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Just started work on this.
It has a motenergy 1003 should be the double brushes.
I have 2 modules from a BMW I3 that I am testing. I gave it a spirited tool around the neighborhood, maybe 20 minutes, and there is a faint electrical smell coming from the motor. Are these things temperature protected at all? I am familiar with brushed motors I used run the ADC 8" in a civic (since gone ac-51) I know they get hot. This is direct drive (4.3 to 1) so maybe all the low speed take offs??
The bike is also probably at 700 lbs Is that too much for this motor?
Thanks for any info

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Anybody know about the sprockets and hubs if they nest into each other? Tried to ask a distributor this question but got no response. This will tell me how much room I will need and how far forward to install new motor plate.
If you mean the sprockets and the Taper-lock bushings, there is nothing in the literature I could find or in my parts bins to look at. The sprockets I do have, for 21mm wide belts(the next width down), have the bushings nearly flush with the backside of the sprocket. If this is also the case with the 36mm sprockets, you won't pick up any overlap room with the bearing. To be sure, you'll probably have to look at the actual sprocket and bushing you intend to use.

If you could move the motor further to the left in the frame, you might pick up more adjustment length for the motor mounting slots. I've usually found that I need more slot length than initially estimated.
 

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Discussion Starter · #43 ·
Here is an update
finally have the drive reduction in and it works great. Thanks to all who helped.
The bike is very quick and has good torque, I have tested a few times off-road once with the chain drive and then again with synchronous belt. Top speed is about 55 which is as fast as I want to go.
the 2 sprockets are just about a degree out of parallel (Gates likes .25 degrees) so I will try to tweak that closer.
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I am going to take everything apart clean up wiring and replace that rear gear with a QD bushing. Since these photos I have added cowling over the belt and gear for safety.
Thanks again, especially Electro wrks, for your input.
 

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Glad it is working out for you. These belt systems are a real game changer for power transmission. To control and adjust the deflection and parallelism between the motor and bearing mounting plates, you could extend the bearing mounting plate up to hold a bolt or threaded rod or two that ties across to the motor mounting plate. Adjustment would be a matter of tightening or loosening nuts on the bolt(s) or rod(s).

Just keep an eye on the belt wear on the inside of the flanges on the sprockets, and adjust accordingly.

You must have slotted the bearing mounting plate for adjusting the belt tension. Most shaft drive bikes don't have the clearance where the dive shaft goes into the swing arm to do this. I recall you wrote that there just was not room to move the motor up and down to tension the belt.

For reference, can you list the type and size of the belt and sprockets and the diameter of the counter shaft and bearings? What's the voltage you are using and how many amps are you drawing at your 55 MPH top speed?

Good work!
 

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Discussion Starter · #45 ·
Used gates parts 1 1/8 driver sprocket and 7/8 driven sprocket:
GATES 8MX-28S-21-1108 TIMING BELT SPROCKET
Gates 1108 1 1/8 Taper-Lock Bushing

Gates 8MX-56S-21 Timing Sprocket
Gates 2012. 7/8 Taper-Lock Bushing

Gates 8MGT-608-21 Poly Chain GT Carbon Belt
96 volts I will have to get back to you on amp draw.
 

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Just by eye estimates, the counter shaft (I guess I've also been calling it a jack shaft) bearing near the sprocket is subject to ~2X the belt tension. ~2 x 600lbs( I think I saw this belt tension load at max torque number somewhere in your posts, and it sounds about right) = ~1200 lbs. This may be too high a load for a 7/8" diameter bearing of this type. Keep an eye on the bearing by checking for excess wear and/or heating from an excess load. You may have to use a larger bearings and shaft diameter to correct this.

Also, flanged bearings are available with a double row of bearings in one unit. This would make your life easier, mounting and belt tensioning wise. AIR they are quite a bit more expensive than the common, regular, single row flanged bearings, like you are using. Some have nice preloaded tapered roller bearings. Again, you need to check the bearing load capacity (side load at the RPM used) to make sure you are working within the bearings limits.
 
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