First build - "KTM SXE"

[Jocke_D]

Hi all.

Been reading for a little while and planning (fantazising) a build for a lot longer. Sorry for what will be a long opening post

Some background...
I've been riding bikes with knobbly tires and supermoto slicks for over 20 years so I have that part of a build pretty clear. The electric stuff is more unknown but I've been part of developing a diesel/battery hybrid drill rig and have basic knowledge about electrics so thought "how hard can it be". Kept looking at specs and trying to understand what I wanted/needed while trying to understand lots of basic stuff.
Since I'm mostly in some sort of competition riding I wanted to set a use case where I would have some chance in competing with my existing bikes. Came up with the idea to build a bike that could compete with my FS450 that has some 58hp on the rear wheel in a supermoto moto of some 14-15minutes. That use case gives that I need lots of power (in bursts) but not that much range. But how much power and range are we talking about? My conclusion was that I have no idea and almost impossible to figure out so I'll have to build a bike and test it out. The decision was then made to build a lower spec bike than I originally thougt as a v0.1 or "proof of concept" and then maybe build a better "v1" later on.
The day after I got the donor frame Stark Future revealed their Varg... As I see it it is impossible to compete with that bike so I'd better just go and buy one of those. But since it is fun to build stuff I'll try to finish the v0.1 and maybe use it as an enduro bike, or if it turns out it can compete with the FS450 I'll use it as first intended.

Since most of what I'm doing at this point is based on guesswork this is my basic spec. Please feel free to question it
Motor: QS 138 70H v3 (probably to small but I really wanted the reduction gear and the price felt better than an ME1616 that I was looking at first)
Controler: FarDriver ND84850 (perhaps to big for the QS but wanted to see how much I can overload it. Remember I have almost no idea what I'm doing)
Battery: 2 modules from a Passat GTE. Each is 12S/28Ah. The battery dictated the 84850 to match max voltage. (thanks to "j bjork" for these)
BMS: Ant BMS (a friend had one he wasn't gonna use)
Throttle: Domino (hopefully. Can someone tell me if it will work with my 8450???)
What am I missing ?

I measured 12.20kg for the QS and 2,95kg for the 84850 if anyone is interested

Since posts without pics are useless here are some. Please try to look beyond the absolute mess in my garage

This is what I bought as a donor bike


Pretty fast I assembled the pile i bought to see what I had.


Then used some stuff that isn't used right now from other bikes to get a rolling chassi


I got some measurements of the battery modules and a very rough approximation of the motors dimension (cardboard tube) and mocked up this to get a _very_ rough idea what it could look like.


I eventually got the motor and controler delivered and started playing with placement.


The battery modules. They are supposed to have a heat sink (water cooled) between them but I'll probablby have to mount them so that won't fit. My idea is to get another and use as protection from impacts.


I don't want to start cutting into the frame before I have a pretty firm idea of where everything goes. I'll try and get an air box to see if the controler will fit inside. My idea is to use as much as possible of the original plastics for better ergonomics and being able to use as much stock mounting hardware as possible. A tank would be great but I guess it will cost a lot. Toying with the idea to mould the tank from my FS450 in fibreglas but we'll see.

This is about as far as I have gotten as of now.
There are four concerns at this point (lots will come later on).
- Will the Domino throttle work with my 84850?
- Are there any restrictions in how I can rotate the motor. My initial idea was to have it a lot higher with the sprocket pointing downward instead as upward as in my pics. This was to get more space for batterys.
- I got absolutely no documentation on the controler or motor. Not a single piece of paper. Where can I find a good source for that (have obviously emailed the seller) ?
- Gearing. I've read both 2.35:1 and 3:1 for the v3. What is it? My plan is to use a 520 drive train. Has anyone done any smart calculations regarding gearing? I want to buy one or two front sprockets so I can use my existing collection of rear sprockets (38 - 52) to get best gearing. Top speed must be 130km/h with the 17" slicks in the rear.

If you have read all this I thank you for your interest

 

[Jocke_D]

This illustrates, in an extremely proffesional way, my initial idea of mounting the motor.
My idea is that the reduction must run in oil but it shouldn't matter if I rotate it as long as I have a proper oil level.

Any thoughts?

 

[j bjork]

Nice, a build thread

I think it should work with a domino, the voltage level can be adjusted with resistors if necessary.
I recommend to do that anyway, to get an offset on the positive so you dont get the full (5v for example) voltage at full throttle.
That is for safety so the controller can see a difference between full throttle and broken ground to the throttle.

From what I remember the gearing should be about 2.3:1, and I think what you have to check is the ventilation when position the motor. But you can see both the gearing and ventilation in the thread about the motor here in ES :thumb:

Edit, here you go:
https://endless-sphere.com/forums/viewtopic.php?f=10&t=110723

 

[Jocke_D]

Nice, a build thread

I think it should work with a domino, the voltage level can be adjusted with resistors if necessary.
I recommend to do that anyway, to get an offset on the positive so you dont get the full (5v for example) voltage at full throttle.
That is for safety so the controller can see a difference between full throttle and broken ground to the throttle.

From what I remember the gearing should be about 2.3:1, and I think what you have to check is the ventilation when position the motor. But you can see both the gearing and ventilation in the thread about the motor here in ES :thumb:

Edit, here you go:
https://endless-sphere.com/forums/viewtopic.php?f=10&t=110723

Yeah. Finally
There has been som ski trips, Corona sickness and some other stuff. Hopefully I'll get to spend some more time now.

Ordered the Domino now!
Being able to detect throttle fault feels like a good idea. We implemented something similar on the machines at work when we figured out that a throttle fault would be considered by the ECU as 100% power = no good since we operate vehicles from 10 - 100 tons

I'll try to read that thread a bit more and do some gearing calculations (I could even open up my own motor and count the teeth). Anyone have an idea of what max rpm will be available?

Good point about the ventilation!
I haven't really looked that much on the motor yet but remember a small hose that was plugged. Don't remember how it was located though.

Side note:
I just learned that one of the hardware/electric guys at work is converting a Beetle so hopefully I'll be able to learn lots of stuff from him

 

[hugok]

I will follow this build

Motor has 1:2.35 gearing and I run it at 6000 rpm with 14/54 sprockets on 18" dirtbike tire with a top speed of 80 km/h.

If you cut the chain gard holder on the motor you could fit bigger front sprocket, otherwise 14 is about the biggest you can fit.

With 14 teeth front sprocket you would probably need to go down to less than 38 teeth on back sprocket to reach 130 km/h.

 

[SlowCo]

I love build threads like these so I'll follow. Good luck and enjoy building :thumb:

 

[Jocke_D]

I'm glad you find it interesting. Don't expect a fast build speed though.
I also try to run a family with two busy kids while keeping the wife happy and not letting the house deteriorate to much

Made some calculations and found that it will be hard to get the speeds I want

With a 160/60-17 and max rpm on the v3 of 6000 I'll only get 111km/h with 14/38 gearing. 15t front only adds 7km/h.
7000 rpm means 129km/h with 14/38. Wonder if this is possible?
I guess that this motor is a bit small for these speeds anyway so I'll stick to my idea of building a v0.1 and see where we land.

On a 140/80-18 with 13/52 it will top out at 82km/h. It will be a killer enduro bike at least

A reduction of 1:1,5 (with max rpm @6000) would have been spot on. For me in this application.
What kind of rpm can you get out of a 180 90H? :wink:


Got an email today that the power supply "is in your country" now at least

 

[hugok]

What if you just mill/cut of the chain guard holder and put a 17 front sprocket. With 17/38 you get about 135km/h @ 6000 rpm.

 

[Paulflieg]

I am building a crf with the qs motor v3... does anyone have a source for the 520 motor sprocket?

 

[hugok]

I am building a crf with the qs motor v3... does anyone have a source for the 520 motor sprocket?

One store in UK sells them
https://mighte.me/product/13t-520pitch-qs-v3-and-70h-sprocket/

 

[Elektrosherpa]

I am building a crf with the qs motor v3... does anyone have a source for the 520 motor sprocket?

Is the shaft of this motor different from the qs138?
For mine I have got various 520 sprockets with perfect fit from "mykettenkit.de"
No comparison to the garbage from qs themselves, aliexpress etc.

 

[Jocke_D]

What if you just mill/cut of the chain guard holder and put a 17 front sprocket. With 17/38 you get about 135km/h @ 6000 rpm.

I had to take it apart yesterday to see what the inside looks like. Could be possible. Can't really figure out what the thread outside of the motor axle is for (besides perhaps a chain guard like you say). I'll look into that. Could be done with an angle grinder in worst case. I'd first like to get a proper, smaller, sprocket and see how it fits.

This is how the reduction looks like
The gearing is 19:45 so slightly worse that 1:2,35 at 1:2,37


Put a 15t to see what it could look like.

 

[Jocke_D]

Is the shaft of this motor different from the qs138?
For mine I have got various 520 sprockets with perfect fit from "mykettenkit.de"
No comparison to the garbage from qs themselves, aliexpress etc.

This is really interesting. Where there any stock sprockets (brand?) or did they custom make them?

 

[hugok]

I would just grind it off since its just a holder for the guard.

If you have access to a lathe you could just mill out the old spline from your 520 sprocket and and to the same on the 428 sprocket you got with the motor and weld them together. Not that much work and you get your 520 sprocket

 

[j bjork]

Is the shaft of this motor different from the qs138?
For mine I have got various 520 sprockets with perfect fit from "mykettenkit.de"
No comparison to the garbage from qs themselves, aliexpress etc.

This is really interesting. Where there any stock sprockets (brand?) or did they custom make them?

I suppose you have the 17mm shaft? The v1 and 2 have 20mm shaft, the earlier with a 4mm spline. For these I think there are both 428 and 520 available. I have posted info in my ktm thread and a few other places about sprockets for those. It seems like the newer motors may have the 20mm shaft with 5mm spline, the same as the 180 90h. I have posted info about sprockets for those in my yamaha thread.

If you have the 17mm shaft there are probably some info about sprockets in the thread I linked to earlier. There you can also look at pictures how the reduction look etc. From what I remember they had some problems with fitment of the sprockets they found, I recommend spending an hour or two at jt sprockets page to get an idea what is available.

 

[Jocke_D]

I would just grind it off since its just a holder for the guard.

If you have access to a lathe you could just mill out the old spline from your 520 sprocket and and to the same on the 428 sprocket you got with the motor and weld them together. Not that much work and you get your 520 sprocket

I generally try to keep away from to specialized parts. Stock is the way to go (or nicely fabricated) :wink:
That being said, I'll keep that idea in the back of my head for future use (didn't get any sprockets at all with the motor unfortunately )

I have asked the guy in the "v3 thread" that made his own sprockets what the status is about those and also sent an inquiry to the german company that was refered in the same thread.
Then there is might.me but the only review I've seen was no good. They also only have a 13t.
I'll try also to get a hold of someone in Sweden that makes sprockets. I know there are some but can't remember right now.

It all comes down to what kind of max rpm I can get, I guess, how critical sprocket size is

 

[hugok]

Check with these guys as well, they had 520 sprockets a while ago.

https://www.electroandcompany.com/

 

[Jocke_D]

I suppose you have the 17mm shaft? The v1 and 2 have 20mm shaft, the earlier with a 4mm spline. For these I think there are both 428 and 520 available. I have posted info in my ktm thread and a few other places about sprockets for those. It seems like the newer motors may have the 20mm shaft with 5mm spline, the same as the 180 90h. I have posted info about sprockets for those in my yamaha thread.

If you have the 17mm shaft there are probably some info about sprockets in the thread I linked to earlier. There you can also look at pictures how the reduction look etc. From what I remember they had some problems with fitment of the sprockets they found, I recommend spending an hour or two at jt sprockets page to get an idea what is available.

Yup. The shaft is 14mm inner / 17mm outer and a 4mm spline (is that the rigt word?). Or at least that is what a drawing said in that thread. Will verify that on my own motor asap.
The JT sprockets I've found so far are all larger but the search continues

 

[j bjork]

I dont know why they use a 17mm on that motor, 20mm should be possible

I dont think there are any (standard)520 sprockets for that shaft, I think the most are mopeds with 420 sprockets.
But it never hurts to look :wink:

 

[hugok]

Yeah I use old Derbi Senda front sprocket, as you said 420 on those.

 

[Elektrosherpa]

This is really interesting. Where there any stock sprockets (brand?) or did they custom make them?

They were stock sprockets.

Dont find the bill right now, but the brand was "JTF".

I ordered "JTF422.12", JTF1903.12" , "JTF421.11" and "JTF1407.10" for testing,
because I wasnt sure about the quality, after my experiences with the garbage from QS and from Aliexpress.
The last one is the one I am actually using.

But after reading the numbers in your post,
I am afraid this wont help you-
my QS138 shaft is 16/20/4 ...

 

[Paulflieg]

I bought a 13t from https://mighte.me/product/13t-520pitch-qs-v3-and-70h-sprocket/ and it was complete dog shite!They could not even drill and tap the holes straight,and lets not start on fitment lol.Keep clear trust me :thumb:

At this price, you should expect at least premium quality... Thanks for the info

 

[speedy1984]

Yeah 100% agree :thumb:

 

[Jocke_D]

They were stock sprockets.

Dont find the bill right now, but the brand was "JTF".

I ordered "JTF422.12", JTF1903.12" , "JTF421.11" and "JTF1407.10" for testing,
because I wasnt sure about the quality, after my experiences with the garbage from QS and from Aliexpress.
The last one is the one I am actually using.

But after reading the numbers in your post,
I am afraid this wont help you-
my QS138 shaft is 16/20/4 ...

Yeah, I found lots of sprockets on their site for 520 in 16/20 but in 14/17 there are only 428.
I am in contact with them to see if they can find anything.

Electrobraap has 13t but I don't know if it is 420/428/520 yet.
Could be the same as mighte.me is offering. In that case it's a 520. 13t will be to small unless I can get 7000rpm out of the motor.

My backup plan is to see if I can get 428 rear sprockets for my hubs. Hopefully with a decent chain it'll work.

 

[Jocke_D]

Summary for me and everyone else who might be looking for sprockets.

Jordan325ic (on the forum)
- PM on forum. Made some sprockets but has none left as of now. Might make more later.

MightE.me
- Looked at their site. Seem to be the only one to have a 520. Only 13t unfortunately. https://mighte.me/product/13t-520pitch-qs-v3-and-70h-sprocket/

Electrobraap
- EMail contact. Only has 428 but in 13 & 15t. Recommends to use 428 with a custom rear sprocket. Also says that I probably can get 7000 rpm but they are not pleased with my chosen controler

JTsprockets
- EMail contact. Doesn't have anything in 520 for the 14/17 shaft but lots of 428. Also no rear sprockets for my KTM hubs in 428 (backup plan)

mykettenrad.de
- EMail contact. Has lots in 428. They are currently investigating my request for a 520 to see if they have anything. I'll ask about rear ones in 428 when they get back to me.


So my options right now are to go with the Mighte.me and a stock 38 rear OR some 428 15t which I probably can get locally.
520 = 13/38 equals 119km/h if I can get the motor to 7000rpm. I have lots of chains and rear sprockets.
428 = if I can get 428 rear sprockets for my hub the gearing options are almost unlimited. Everything needs to be bought new.

Any ideas if it is a risk to use the 428? Will I risk to break it?
Are there any 428 rear sprockets available anywhere?