Clunking/popping in mid drive by pedals?!?

[Stoogecurly]

Hey guys iv only had my bike up and running afew months and took it on maybe x3 2 mile trips and now im getting a loud clunking that i can fell and hear though my pedals im not sure if its my cassette, motor or what when im giving it throttle. It dont always happen but when it does its so loud and jerks the bike so much it gives you a good startle.

Its a trek mountain bike with the cyclone 6kw mid drive with 72v battery.

 

[neptronix]

That probably comes from a very rapid engagement of one or many of the various clutches in this system.
Way too much initial torque..

If you have a programmable controller, best thing to do would be to lower the phase amps somewhat to dull the initial torque.. this will help preserve the life of your drivetrain as a whole ( which is rated for about a tenth of the power you're putting into it from a stall, so that's pretty important )

 

[Chalo]

Please inspect the chainring and cassette sprocket teeth to see if any of them are broken, shortened, or rounded off. I once did a gear replacement on a BBSHD to address some horrible crunchy mechanical sounds that once I got into the job, were obviously attributable to ruined chainring teeth.

 

[Stoogecurly]

Thanks for the replys! So phase amps is the initial torque?? I cant find much on what each of the aetting in the control really does. I know i had to put soft start up to a 10 because she just wants to flip me over when i give it throttle.

 

[neptronix]

Yeah the phase amp to battery amp ratio tends to be about 2:1-3:1 on most controllers. it strongly affects the torque curve. Tuning the ratio close to 1:1 will make most electric motors have torque curves like gas engines. >4:1 would probably make for a quick end to either the controller or drivetrain the second you nudge the throttle.

 

[Stoogecurly]

These are the settings i have currently any adjustments you may think of? Setting the phase amp low did help out but it wont go below 50%

 

[Chalo]

Did you check the chain and sprockets? If you run it in top gear all the time like it is in the photo, then that's likely the problem. At least do a fault check by shifting over a few gears on the cassette to see if the problem goes away.

The 11 tooth sprocket is very destructive to your chain drive, even when used with only pedal power.

 

[Manbeer]

and holy hell, i can only imagine trying to keep the front wheel on the ground with that motor and the battery back there!

 

[markz]

Stoogecurly will be back wondering why his rear rack broke and ask which rear rack to buy next.

 

[Stoogecurly]

Lol yea i know its back heavy like a sob. im making a design in my 3d program to 3d print a case in the center of the bike. I just printed a simple case for the back to get me up and running. Haha its not a permanent deal. I adjusted the amp phase and put my bike on a lower gear and shes running like a champ. If i go up one higher it starts to do that popping sound. So im going to assume using that motor in all other gears is not a good idea if it does that. Also im not sure whats doing that loud clunk/popping is it moror or chain or sprokets? I could mount a gopro but it aounds like everyone if familiar with this issue.