questions/issues on my cemoto pas and pas in general


Well-Known Member
this is kind of a long story

the cemoto full suspension mtn bike from electrobikeworld was the first bike i bought about a year ago

i had not been on a bike in 30 years and it seemed way too fast for me , and the pas seemed way too powerful

think this is a cadence sensor pas, it has a 5 magnet disc
it is a 36volt 8.8? battery with 350 watt motor i think
has one speed pas with a 5 magnet disc and throttle with override

anyway right after i got it took it to a guy that does some ebike work in tucson and he took 2 magnets out of the disc trying to slow the motor down for me

with these 2 magnets out is pretty much the only way i have ridden it since i got it

at first i wasnt sure how much it changed but as i rode more it seemed ok, but it was surgy
looking back would guess i had 30-50% pas this way and a good jump forward using the throttle override when i wanted to
would easily get 30-35 even 40 miles out of a battery

rode it some but not a lot, but i did get more comfortable with the bike, higher speeds etc

in the meantime i have learned more and wondered if my inconsistent cadence was causing that surging? now my cadence is much better....

anyway decided i should fix the magnet disc hoping the surge would go away and thinking i am fine now with a faster bike etc, should be better right....

got a couple of similar size ones with 5 magnets off ebay, seems like they were 2.55 and 2.65 sizes
we matched the disc that was in it and the LBS put the new 5 magnet in a week ago

rode the bike once and thought it was way faster, a little too much pas but still pedalling in 5-6 i had good resistance and the bike was doing 15mph easily, it was ok
just thought it was a little faster and i was ok with that , was still pedalling hard and getting a good workout, just kind of fast
but i burned up way more of the battery than usual, like double

tonite i tried to ride it and the pas is 100% on, in the flats could not keep any resistance on the pedals at all in any gear and the throttle overrride had nothing, the motor was wide open as soon as i barely pushed the pedals

rode with no electric for a while, then stopped to see if i could adjust the sensor
found that the disc is just riding on that spindle and i could move it in/out and this would affect the pas

stopped several times and adjusted it, moving it slightly away from the sensor slowed down the pas some
but it was up and down, 3 minutes with some assist but then it would cut out for a minute or 2 completely and then come back

move the disc in a little more and get more pas, too much really
could not find a perfect spot and no mater what eventually it is going to move some i would think because it is just riding on that spindle..

questions are this

is this how this simple 1 level pas is supposed to work? wide open power? it seems the assist should be maybe 50% and then the throttle would override and take you to 100%
to me it seems this is malfunctioning??
or is it that the disc is not set right location wise and that it needs some kind of stop to keep it in place?

or if this is correct is the only solution removing a couple of magnets again?

any thoughts on all this would be great
cemoto713 hope you chime in and let me know if your pas works wide open like that with zero left in the throttle? or if yours acts different

i need this bike some when friends ride with me, most of the time i will ride this bike and they will ride the street or prodeco
so want to get it fixed even if i just have to take out some magnets

thanks for any help!!!


Well-Known Member
You were on the right track with magnet removal, but did you put the three magnets 120 degrees apart (equally spaced)? My hypothesis is the controller is trying to average the spin rate, and the uneven magnet spacing affects its algorithm.

You should buy a pedal/crank arm puller tool and learn how to pull pedal arms. They're under $10 on ebay, or $15-20 at your local bike shop, but the ebay models usually are turned with socket wrenches, so they have more pulling power. Bike shop tools usually have a finger crank, so offer less force. Good reasons for both types. Watch a you tube video on how to use them. Always remove the but or bolt inside the pedal or you ruin the pedal and break the tool trying to remove a pedal that cannot come off.

With a pulling tool, and a bike that already has had its arms taken off twice, your Cemoto arm should fall off with a nudge. Now you can put teflon tape on the shaft or something else to keep your magnet disk fixed.

Spacing between the disk and sensor matters. The direction of the disk matters. I recently put one on backwards and PAS only worked in reverse. The strength of the magnet matters. If it is too strong, maybe the sensor cannot tell that the magnet gas moved away. This is probably not your problem.

I would even get the original disk. Drill three holes equally spaced. Or if you still have the other two magnets, try 4. Glue the magnets on the new positions. Make sure the magnets are all oriented with their north/south poles in the same direction (remember what I said about my PAS working backwards).

If you have the capability of doing this PAS sensor yourself, it's just a mechanical spacing issue.

My bikes all have multi-level PAS sensors, but if I released a bike with only one level, sure, I would set it to max .


Well-Known Member
harry thanks for the reply
the bike is useless set to max, i cannot even pedal it and have any resistance- at least when the disc is at all close to the magnets

agree that i need a correctly spaced disc with 3-4 magnets but am not seeing any on ebay, etc
guess we would have to make one

with a system like this is there any kind of plug in/wire in display etc- cycle analyst or something that would allow me to control the power of the pas? or do you have to change out the entire controller? and is changing the controller hard to do?

really like this bike, epsecially the battery inside the frame, it is comfortable to ride
would like to fix this issue

i will play around with the distance on the disc/sensor set up more
is there a normal set spacing designation for these type systems?