QS 3000w midmotor

Qs made an important commercial gesture on shipping costs when ordering a Qs 138 90H and they supplied the motor shaft for the 70H in addition to 2 different gears.
The video :
https://youtu.be/ExonkHtjLsg
 
I have the new V2 138 motor with the spine shaft. I wanted to fit a 520 sprocket - anyone managed to do this without any issues?
 
The latest version of the Qs 138 70h in version 2 is now available with the keyed motor shaft for a pulley and an adapter for a 428 14T pinion. It's good news.
https://fr.aliexpress.com/item/1005001631600681.html?spm=a2g0n.search-amp.list.1005001631600681&aff_trace_key=17d206a2c5c045ba8e828475b71161f0-1606503191170-01137-UneMJZVf&aff_platform=msite&m_page_id=7444amp-3V2n6DINbfJB-E9_mmS-3g1607409439110&browser_id=382960e3e1a44046a8daae5d3d1b9f02&is_c=N
 
Shazzy said:
I have the new V2 138 motor with the spine shaft. I wanted to fit a 520 sprocket - anyone managed to do this without any issues?

JTF1903 sprocket. Ebay got lots of them. Its a tight fit if the motor is brand new, but if it has been running with the sloppy stock sprocket it glides right on. Nothing a small dead blow hammer wont fix, though.
 

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You should replace the 2 sprockets with larger diameter models to reduce the stress on the motor and reduction shafts as well as the chain. You can keep the same ratio between the 2 sprockets, but simply increase the number of teeth on the 2.
 
Hello, bringing up the sprocket thing again, i got the QS 138 90H 4kw with the Tapered Hub.
It comes with an 14t sprocket, wich looks very very bad :? , and i dont want to shred a chain on it.. :wink:

Did anyone find an fitting sprocket for this tapered shaft ? (looks like the Pulley mount shaft, page 11 this thread)

(tapered from 25mm to 21 with woodruf key)
 
PITMIX said:
Qs made an important commercial gesture on shipping costs when ordering a Qs 138 90H and they supplied the motor shaft for the 70H in addition to 2 different gears.
The video :
https://youtu.be/ExonkHtjLsg

How do you plan to swap the rotor shaft? Are the laminations just keyed in place? No epoxy or anything holding them there?
 
I don't know it's not my motor and my friend hasn't tried replacing the shaft yet. For the moment he has welded the pinion, and if one day the shaft breaks he will replace it.
 
hey how do you guys remove the pulley from the motor? i got a QS 138 90H 4kw and already broke my bearing removal tool. the bolt nut was hard but my inpact wrench did the job.
157750709_337986617613457_4662724328720175229_n.jpg
 
heat up the sprocket with a butane burner used for copper pipes.
 
You must use a plumber's claw wrench to lock the pinion and a wrench with an extension to remove the nut. With an impact wrench it does not work. The nut is glued with varnish, it needs to be heated slightly.
 
Already remove the nut , now i have to wait for a new removal tool. I will try to heat up a bit carefully , dont wanna damage the seal.
 
You don't need any special tool to remove the pulley just have a rubber mallet and a triangular shaped shim to insert between the pulley and the motor flange. With a few small blows of the mallet the pulley will come out. If you damage the seal it is easily replaced. The reference is written on it, it is a standard model.
 
Does anyone have real world Kv’s of the 138 3kW vs the 4kW.
On my bike, I have a massive 82t rear sprocket to get the performance I’m looking for. But it’s just too easy for the chain to get full of mud and cause problems.
Wondering if the 4kW 138 90, may have a lower Kv.
Would love to be able to keep the simplistic single reduction.
 
The data of the engines are real in the descriptions. The Qs 3kW has an actual kV of 73. The Qs 4kW runs at 7000rpm maximum so the kV is 97.
 
I agree, my 70 has a Kv of 60 and this corresponds to the nuc controller reading of 300eKv for a 5 pole motor. The 2kw qs 120 only has a Kv of around 38.
Was hoping the 90h may of been less then the 70, but looks likes it could be much higher.
 
Higher kV means more amps / torque at low speeds right? Slower top speed?

That's what I want.

Why do people use the 3kW / 4kW designators?

138 205 273, coupled with the 50h 70h designator

is just so much clearer. What do those latter actually refer to?
 
A higher kV means that the motor runs faster for the same voltage. kV =RPM/Volt.
The speed of the vehicle will depend on the transmission; for the same transmission the motor with the larger kV will make the vehicle run faster. The kV 73 I get it in Foc mode, 5920rpm with 20s battery. Without this effectively the kV is 60.
 

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I think the goal is to approach the maximum speed of a motorcycle heat engine. With this engine you would need a 2-speed gearbox.
 
PITMIX said:
You don't need any special tool to remove the pulley just have a rubber mallet and a triangular shaped shim to insert between the pulley and the motor flange. With a few small blows of the mallet the pulley will come out. If you damage the seal it is easily replaced. The reference is written on it, it is a standard model.
Be very careful, this can damage the bearings. Best to use some gentle heat to warm the sprocket and the correct extractor tool to pull it off the shaft.

Cheers
Tyler

 
Yeah i will do it like you said, im just waiting for bether quality tool. Got a 10 tooth tapered custom made from uk on the way. Its a bit longer in the shaft but is probably the only choise at the moment.
 
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