Obee Posted May 30, 2021 Share Posted May 30, 2021 (edited) The algorithm steered me towards euc world when I was pandemic googling electric bicycles. July of last year I got KS 18XL as starter wheel. I have over 1000 miles on this wheel with no issues or problems whatsoever. I have crashed it many times and it has some cosmetic character but rides like new. Today I have three wheels. The 18XL, a KS S-18 and a Mten3. Of those three the only one I could hop on and ride today is the 18XL. Mten3 has a flat tire. The S-18 developed a motor issue. It started with a clunk when going from reverse to forward abruptly and grew to a grinding noise while riding and ended with a wheel that doesn't want to rotate. At least I hope it's the motor because I ordered a replacement. And now the moment of truth because I haven't done any dissembling and repair until now. Now I have an Mten3 tube and the option of going tubeless. And I have a S-18 motor ready to be swapped out. I admit it's a bit intimidating and I haven't started either project yet. I very much love riding these eucs. The S-18 (with about 500 miles on it) is my favorite with 18XL close behind. But this can't be a sustainable hobby unless I can repair these things. I have thought about getting a Sherman but my rule now is: if I can't fix what I have I shouldn't get anything else. The ride of S-18 just before it seized up: Edited May 30, 2021 by Obee Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 30, 2021 Share Posted May 30, 2021 12 minutes ago, Obee said: The S-18 developed a motor issue. It started with a clunk when going from reverse to forward abruptly and grew to a grinding noise while riding and ended with a wheel that doesn't want to rotate. At least I hope it's the motor because I ordered a replacement. Unfortionately chances are high for a fried motherboard (blown mosfet). Motor are very hard to kill. Once you open the wheel and disconnect the motor wires turn the motor again - it most probably will turn without resistance now. This is a sign of a blown mosfet causing a short curcuit between the motor wires. Quote Link to comment Share on other sites More sharing options...
Obee Posted May 30, 2021 Author Share Posted May 30, 2021 (edited) 13 minutes ago, Chriull said: Unfortionately chances are high for a fried motherboard (blown mosfet). Motor are very hard to kill. Once you open the wheel and disconnect the motor wires turn the motor again - it most probably will turn without resistance now. This is a sign of a blown mosfet causing a short curcuit between the motor wires. That's interesting. This wheel is actually still operating. It makes horrible noises though. Would a blown mosfet allow it to still operate like this? My description of "doesn't want to rotate" might have been misleading because it does rotate (with resistance) and can actually be ridden. Edited May 30, 2021 by Obee 1 Quote Link to comment Share on other sites More sharing options...
Roadpower Posted May 30, 2021 Share Posted May 30, 2021 That sounds like mechanical noise. Did you use a light to look at the wheel under the case? 1 Quote Link to comment Share on other sites More sharing options...
Chriull Posted May 30, 2021 Share Posted May 30, 2021 54 minutes ago, Obee said: That's interesting. This wheel is actually still operating. It makes horrible noises though. Would a blown mosfet allow it to still operate like this? Ah - ups. No, sorry. No operation possible with a blown mosfet. Too fast with assumptions after wheel does not rotate...;( Quote My description of "doesn't want to rotate" might have been misleading because it does rotate (with resistance) and can actually be ridden. Take a good look, like @Roadpower wrote if not just something is stuck between tire and case. Once open it you can check all places, pedal hanger screws, plastic shell integrity, etc... does not sound too bad on this vid btw: are there any circular scratches on the motor case? Quote Link to comment Share on other sites More sharing options...
Obee Posted June 4, 2021 Author Share Posted June 4, 2021 Finally took it apart and put it back together. There was no sign of a foreign object obstructing anything. It does seem to have been the motor. New motor is in place and the project was a success! The work was basically exactly what you would need to do to fix a flat tire so it wasn't a particularly hard job. But for me it was a very satisfying milestone suggesting the hobby is something I can manage on the mechanical side! Quote Link to comment Share on other sites More sharing options...
tch_popeye Posted June 7, 2021 Share Posted June 7, 2021 Not familiar with those models... would the replacement motor have included new bearings? Your initial description had me thinking “bearing replacement”. This is still something you can investigate further, with the old motor now on top of your workbench. Quote Link to comment Share on other sites More sharing options...
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