Eyss Posted December 21, 2021 Share Posted December 21, 2021 Hi! Having a weird issue with my Sherman that I for the life of me cannot figure out History Sherman has done 6000km Mainly road with tiny bit off-roading It does not snow where I live I have ridden the Sherman through puddles and rain Bearings were changed at 2500km with NSK 6004VVCM bearings The knocking noise started around 4500km after going on a trail. Observations Seems to be related to heat. it'll start after 2-6km depending on the outside temp and then go away the next day until 2-6km of riding It starts off very subtle but gets worse and worse Its not related to speed. it'll happen at 10kph and 50kph It only knocks when I move the Sherman side to side (i.e. carving) on free spin there is a rumbling like a off balanced washing machine? The Sherman behaves perfectly fine otherwise Free spin: knocking: Troubleshooting I have disassembled and checked The motor case screws are tight The axle nut is tight The pedal hanger screws are tight The batteries are secure The side casing screws are tight Have changed the pedals back to stock in case that was causing the issue Any suggestions? Quote Link to comment Share on other sites More sharing options...
Mango Posted December 21, 2021 Share Posted December 21, 2021 Possible actions to take: Inspect for cracked housing near the axles. Inspect pedal hangers. Inspect for worn or damaged washers. Inspect for bad bearings. All will need to be replaced with new parts. Quote Link to comment Share on other sites More sharing options...
Eyss Posted December 21, 2021 Author Share Posted December 21, 2021 20 minutes ago, Mango said: Possible actions to take: Inspect for cracked housing near the axles. Inspect pedal hangers. Inspect for worn or damaged washers. Inspect for bad bearings. All will need to be replaced with new parts. Thanks. Housing is good Pedal hangers seem good The washers are rusted but seem like they are good. Bearings are a bit harder to check but without opening the motor they seem good. Possibility shims? they don't seem to fit quite right when done up Quote Link to comment Share on other sites More sharing options...
Rawnei Posted December 21, 2021 Share Posted December 21, 2021 Similar symptoms that a friend had on a 16x, it was actually the metal casing of the motor having large cracks in it and making a knocking sound from pressure and was getting worse over time so inspect the metal casing on the motor look for cracks. Quote Link to comment Share on other sites More sharing options...
Eyss Posted December 22, 2021 Author Share Posted December 22, 2021 6 hours ago, Rawnei said: Similar symptoms that a friend had on a 16x, it was actually the metal casing of the motor having large cracks in it and making a knocking sound from pressure and was getting worse over time so inspect the metal casing on the motor look for cracks. Thanks. I did inspect the motor case and couldn't see any cracks. I think I'll need to open the motor to inspect further. And might as well change the bearings while I'm there. Quote Link to comment Share on other sites More sharing options...
Eyss Posted December 24, 2021 Author Share Posted December 24, 2021 So I tried to inspect the bearings but since I used silicone to seal the motor when I changed the bearings before, I can't seem to open the motor up. It does seem like the bearing is the issue. When I heat it with a blow dryer, it'll pop and then it'll creak when you put pressure on it. When cold it doesn't make any noise. Not sure how to open the motor. Might just have to live with the noise. Quote Link to comment Share on other sites More sharing options...
Eyss Posted December 30, 2021 Author Share Posted December 30, 2021 So an update: A friend helped me open the motor and I was able to investigate further. The cause of the noise was the housing that hosts the bearing had expanded and so the bearing was moving side to side. I was able to find similar issues occuring in motorcycles and they suggested using green Loctite to secure it. I did this yesterday and went for a ride and seems like the noise has gone away now. 2 1 Quote Link to comment Share on other sites More sharing options...
Rawnei Posted December 30, 2021 Share Posted December 30, 2021 Good job, glad you found and fixed it, a lot of time and effort I imagine. Quote Link to comment Share on other sites More sharing options...
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