Stark weird noise and no crawl/ reverse... Drive train not reacting to throttle inputs

[Aleksandar13]

Hi All,

My turn to post some issues with my stark. It's a gen 2 with 7 hours on it and it was faultless so far, suspension revalve today and when I picked it up took for a spin in the car park was good with no issues at all... Then stopped and once I tried to put in gear it did go into gear but as soon as I tried to apply throttle the bike made a noise from the sprocket like it spins o the inside and the wheel didn't move.
Put on the stand and inspected the sprocket nut, also my dealer was on the phone to me within minutes and video as well guided me through what to check... The inside of the gearbox is tight and all bolts are OK, it spins freely with no noises whatsoever...

It does not respond to throttle inputs of 5 to 10 percent, literally the wheel doesn't move but when you are giving the throttle blips it has tendency to move the wheel... Also it skips the initial throttle pick up and it's like it sits in neutral and just jumps into gear... Hard to explain..

Crawl and reverse are not working at all... Opened a sfark log and looking forward to their response...

I'm optimistic about it not being mechanical in the gearbox or motor but who knows!? Also can it be related to loss of calibration between the input in the software... Kind of like it doesn't know at what position it is in the rotation etc... I'm no expert here.

 

[Chaconne]

I would check the connections under the front plate. Both the power and throttle connect in a junction box there at least on the gen 1. Since your suspension guys were likely messing with the forks it would be easy for them to bump into that junction.

Also, that crawl and reverse are not working point possibly to the switch or its connections which connect at the junction (which is suspect since both the power button and throttle seem to be effected). Check to see if it was messed with and also make sure if they disconnected it, it was reconnected properly.

Usually software doesn't lose its mind out-of-the-blue but you never know.

 

[Aleksandar13]

I would check the connections under the front plate. Both the power and throttle connect in a junction box there at least on the gen 1. Since your suspension guys were likely messing with the forks it would be easy for them to bump into that junction.

Also, that crawl and reverse are not working point possibly to the switch or its connections which connect at the junction (which is suspect since both the power button and throttle seem to be effected). Check to see if it was messed with and also make sure if they disconnected it, it was reconnected properly.

Usually software doesn't lose its mind out-of-the-blue but you never know.

Makes sense, thank you. I'll start there and there take the main body off today and see what's what. Fingers crossed

 

[fsfs]

Hi All,

My turn to post some issues with my stark. It's a gen 2 with 7 hours on it and it was faultless so far, suspension revalve today and when I picked it up took for a spin in the car park was good with no issues at all... Then stopped and once I tried to put in gear it did go into gear but as soon as I tried to apply throttle the bike made a noise from the sprocket like it spins o the inside and the wheel didn't move.
Put on the stand and inspected the sprocket nut, also my dealer was on the phone to me within minutes and video as well guided me through what to check... The inside of the gearbox is tight and all bolts are OK, it spins freely with no noises whatsoever...

It does not respond to throttle inputs of 5 to 10 percent, literally the wheel doesn't move but when you are giving the throttle blips it has tendency to move the wheel... Also it skips the initial throttle pick up and it's like it sits in neutral and just jumps into gear... Hard to explain..

Crawl and reverse are not working at all... Opened a sfark log and looking forward to their response...

I'm optimistic about it not being mechanical in the gearbox or motor but who knows!? Also can it be related to loss of calibration between the input in the software... Kind of like it doesn't know at what position it is in the rotation etc... I'm no expert here.

If not mechanically binding when turning by hand... then most likely problem with rotor position sensor (motor rotor) itself of with communication between the inverter and sensor. Or sensor magnet has become loose.

 

[Aleksandar13]

If not mechanically binding when turning by hand... then most likely problem with rotor position sensor (motor rotor) itself of with communication between the inverter and sensor. Or sensor magnet has become loose.

After a night in the garage the bike runs fine and everything is OK from a first test on the stand. I've taken the headlight off and checked all throttle connection underneath the headlight sprayed them with contact spray and put back together.
I might have been a bit enthusiastic with the power washer and some water might have been the cause for all of this. Don't know but it seems fine now..
Engages in gear and all modes with no noises or anything.
Thoughts about my theory?

 

[Theo]

Well, your bike has been sold as street legal with head lights, right? So one possibility is that who has installed those head lights has somehow affected the way in which stock powertrain works, possibly causing problems. If the headlight uses some 12V battery hidden somewhere that you recharge separetly, then this shouldn't be the issue, but if there is for example a DC/DC converter which takes electricity from the main battery and converts it into 12 V, then maybe it can cause problems depending on how it has been done.

 

[fsfs]

After a night in the garage the bike runs fine and everything is OK from a first test on the stand. I've taken the headlight off and checked all throttle connection underneath the headlight sprayed them with contact spray and put back together.
I might have been a bit enthusiastic with the power washer and some water might have been the cause for all of this. Don't know but it seems fine now..
Engages in gear and all modes with no noises or anything.
Thoughts about my theory?

My first guess is water ingress -- just like you said -- it dried off given time and now works fine. Sealing is a Varg weak point.
My second guess is a mechanical connection problem like a cold solder joint or poor wire crimp or connector. Here the temperature can make a difference where thermal expansion and contraction make and break a connection.

Each electronic component (battery, inverter, vcu, etc) has a humidity sensor. Stark should be able to look and if there is a spike in humidity followed by a gradual drop that points to water ingress.

 

[Aleksandar13]

My first guess is water ingress -- just like you said -- it dried off given time and now works fine. Sealing is a Varg weak point.
My second guess is a mechanical connection problem like a cold solder joint or poor wire crimp or connector. Here the temperature can make a difference where thermal expansion and contraction make and break a connection.

Each electronic component (battery, inverter, vcu, etc) has a humidity sensor. Stark should be able to look and if there is a spike in humidity followed by a gradual drop that points to water ingress.

Update, got to the green lanes unloaded the bike and it done it again... Took all the body work off and went through each connection with contact spray. Started up working fine. Got into neutral didn't work again. I've connected the stark phone to Internet rebooted the bike and it's been fine for the last 30 min with me riding up and down etc.
Could it be possible that the bike and the app were not in sink or calibrated... Fingers crossed it's all good now. On the positive side you can see the good engineering gone into the bike it's so easy to work on. Just hope the issue is fixed... Will get stark to log the bike and see if they find traces of a faulty code...

 

[Chaconne]

Update, got to the green lanes unloaded the bike and it done it again... Took all the body work off and went through each connection with contact spray. Started up working fine. Got into neutral didn't work again. I've connected the stark phone to Internet rebooted the bike and it's been fine for the last 30 min with me riding up and down etc.
Could it be possible that the bike and the app were not in sink or calibrated... Fingers crossed it's all good now. On the positive side you can see the good engineering gone into the bike it's so easy to work on. Just hope the issue is fixed... Will get stark to log the bike and see if they find traces of a faulty code...

Stark should be able to log onto you bike and get the logs. Your bike worked fine up until you had the service done on your suspension correct? Could be water got into something with the powerwashing. Like all European bikes the Stark tends to be open to water ingress (KTM is terrible with this)

But it is a very weird correlate if your bike worked great up until you take it for service at the shop and now it is behaving in a flakey way. I would inspect for wire damage not just connectors especially where they may have been working on your machine.

 

[rayivers]

Also can it be related to loss of calibration between the input in the software... Kind of like it doesn't know at what position it is in the rotation etc... I'm no expert here.

Fwiw, this is what it sounds like to me too - like there may be two zero-throttle FW numbers (the original/correct one that's loaded at bike turn-on, and the new/erroneous one that appears after a kill-throttle command (i.e., 'neutral') indicating zero is at 10% rotation or whatever. I wonder what happens if the throttle's held open a bit when neutral or turn-on events occur by mistake, maybe from unfamiliar mechanics working on the front fork.

 

[Aleksandar13]

Fwiw, this is what it sounds like to me too - like there may be two zero-throttle FW numbers (the original/correct one that's loaded at bike turn-on, and the new/erroneous one that appears after a kill-throttle command (i.e., 'neutral') indicating zero is at 10% rotation or whatever. I wonder what happens if the throttle's held open a bit when neutral or turn-on events occur by mistake, maybe from unfamiliar mechanics working on the front fork.

I think you are spot on, don't really know what fwiw means but... I think I got it back on track...
Basically after shutting it down and letting sit for 5 min it turned back on and rode it for 10 min without letting it go into neutral I figured it's software related or something because all the wires have been checked unplugged and cleaned so it couldn't be that. I've then connected the stark phone to the WiFi whilst the bike was on and in gear and after doing this the bike just started working as it should with no issue at all.. I rode for 45 min with stops and neutral and everything seems OK now....
I don't know if it's my fault but I started the bike yesterday with the phone being shut down and I don't know if this might have triggered something like a glitch and needed WiFi to operate normally again...
On a positive note my friend tested it with a broken leg and he will get one

 

[rayivers]

That's great! - hope for the best with the throttle, and maybe your friend's discovered a new use for electric bikes (quicker return to riding after serious injury). For What It's Worth I didn't know what fwiw meant either, and so many others too. Another thing... does your throttle itself have any new marks on it, or show signs of having rotated on the bars after the suspension work? Some Altas had problems if the throttle was rotated forward (the Alta Hirschmann throttles had a microswitch, possibly for a future reverse mode), but I believe this was fixed in later FW releases.

 

[Aleksandar13]

That's great! - hope for the best with the throttle, and maybe your friend's discovered a new use for electric bikes (quicker return to riding after serious injury). For What It's Worth I didn't know what fwiw meant either, and so many others too. Another thing... does your throttle itself have any new marks on it, or show signs of having rotated on the bars after the suspension work? Some Altas had problems if the throttle was rotated forward (the Alta Hirschmann throttles had a microswitch, possibly for a future reverse mode), but I believe this was fixed in later FW releases.

The only thing I could see different on the bike is that there is a connector in the middle of the bike round one which was very easy to remove almost like it wasn't closed together properly and it could move... Cleaned and put back together and still had the same issue until I've connected the WiFi. Weird thing... Throttle hasn't been touched.
On another positive note... The bike is so easy to work on and we have taken everything apart and put back together cleaned on the side of the trail within 45 min...
Once we got it up an running it was bliss with the new suspension revalve but more on that on my other thread.

 

[fsfs]

The only thing I could see different on the bike is that there is a connector in the middle of the bike round one which was very easy to remove almost like it wasn't closed together properly and it could move... Cleaned and put back together and still had the same issue until I've connected the WiFi. Weird thing... Throttle hasn't been touched.
On another positive note... The bike is so easy to work on and we have taken everything apart and put back together cleaned on the side of the trail within 45 min...
Once we got it up an running it was bliss with the new suspension revalve but more on that on my other thread.

The phone should really have nothing to do with it. That round connector is very important as it connects the VCU to the inverter (motor controller). I don't think it is software -- it is behaving like you have a loose connection, bad wire crimp, or water in the system somewhere.

Edit: the round connector is easy to take apart, a simple twist will do it. Be sure that that connector is mated correctly (the twist mechanism makes an affirmative lock when you push it together).

Second edit: Are the map buttons working; do the LEDs respond to the map buttons? Do you see the map number change on the phone? Can you enter forward and reverse crawl mode with the buttons?. If so, then the map buttons to the VCU are working correctly and the problem is likely with the inverter/motor controller. However, if pressing map down does not put the bike into gear (LED keeps flashing) then it is likely the map switches or VCU. You don't want it to be the inverter as that a more difficult fix/swapout.

 

[Theo]

Anyhow, even though I think it's unlikely to happen, if it starts behaving strangely and accelerates more than it's supposed to do given a certain throttle position, remember that pressing the power button on my gen 1 puts it back into neutral even if the throttle is open; I guess it should work the same with your Varg. I mean that we don't have a clutch to pull in those situations but we can push the power button instead.

 

[Aleksandar13]

The phone should really have nothing to do with it. That round connector is very important as it connects the VCU to the inverter (motor controller). I don't think it is software -- it is behaving like you have a loose connection, bad wire crimp, or water in the system somewhere.

Edit: the round connector is easy to take apart, a simple twist will do it. Be sure that that connector is mated correctly (the twist mechanism makes an affirmative lock when you push it together).

Second edit: Are the map buttons working; do the LEDs respond to the map buttons? Do you see the map number change on the phone? Can you enter forward and reverse crawl mode with the buttons?. If so, then the map buttons to the VCU are working correctly and the problem is likely with the inverter/motor controller. However, if pressing map down does not put the bike into gear (LED keeps flashing) then it is likely the map switches or VCU. You don't want it to be the inverter as that a more difficult fix/swapout.

Thanks for the response... So for what I can gather after 2 days of fuffing about with the bike and checking all the connections on the bike spraying them with wd40 fast drying connection spray... The bike started normal went into crawl and reverse and any other map you'd want to... You ride it for 5 min or 10 and if you don't allow it to go in neutral it's all fine as soon as it goes into neutral and you put it back into map 1 it kind of forgets the position of the throttle and only responds to throttle inputs that are higher then 30 percent or harsh movements on the throttle with the motor making a jurky noise and responding to that thrtolle input ( I guess not having a clutch it makes is very abrupt and unusual). Also if this happenened crawl and reverse don't work anymore.
After I've connected the phone to WiFi it worked... That's the only explanation I can find until stark have logged the bike and come up with a more logical explanation. Might have been a loose connection and the bike needed a calibration? Which can only happen over WiFi? Don't know... Hopefully it works from now with no issues

 

[Upinsmoke57]

I have to add that I think it's a major design flaw to have a huge opening on the upper triple clamp that feeds water to a somewhat sealed wiring box below. What on earth were they thinking??? They might as well make the box open beneath so it at least drains. My solution will be to make a silicone plug that perfectly fits that hole up top. Every time you wash the bike water goes there!

 

[Aleksandar13]

I have to add that I think it's a major design flaw to have a huge opening on the upper triple clamp that feeds water to a somewhat sealed wiring box below. What on earth were they thinking??? They might as well make the box open beneath so it at least drains. My solution will be to make a silicone plug that perfectly fits that hole up top. Every time you wash the bike water goes there!

You are right about the box the three leading cables from the throttle to the bike and vice versa should have been in a sealed environment... Making it watertight is not impossible and it would be fairly easy so I will have a look at that at some point.

 

[Theo]

I have to add that I think it's a major design flaw to have a huge opening on the upper triple clamp that feeds water to a somewhat sealed wiring box below. What on earth were they thinking??? They might as well make the box open beneath so it at least drains. My solution will be to make a silicone plug that perfectly fits that hole up top. Every time you wash the bike water goes there!

I have thought about that problem, too. Maybe we can find a quick way to cover the opening before washing the bike, like some people cover the air filter of gas bikes.

 

[Aleksandar13]

I have thought about that problem, too. Maybe we can find a quick way to cover the opening before washing the bike, like some people cover the air filter of gas bikes.

I guess the solution is a semipermanent fix with an IKEA zip type bag that can be fitted on top with the opening down and locked and then secure the box to the bike... Or silicone the crap out of the joints and iv you ever need to get in there cut the silicone with a sharp blade... The latter one should be better and it's not a maintenance item in there so you won't need to check that regularly.