Is it normal for engine to turn bicycle pedal around?

[John-Forrest]

I just went on a long trip and there were a lot of lot steep hills. Somewhere along the way, the pedal and pedal arm starting acting like it was coming loose. I went to a bike shop; the guy told me the bike part seems fine but there may be loose bearings in the engine sprocket. Anyway, now the engine is making the bicycle sprocket fly around. I have to hold my feet on the pedals to keep it from flying around at the same speed the engine is turning. Every rotation there is some kind of weird knock.


I'm definitely feeling nervous to ride this like this. Sometimes bike pedal flies around VERY HARD! Like it could break an ankle bone or something. I have to stand on pedal to keep it from moving around.

Anyone have any idea what might be happening? Could have anything to do with clutch not completely disengaging bicycle sprocket/chain?

 

[HERPER]

do you have a coaster break? because if so my bike had the same thing. the bearings inside the coaster broke and jammed the brakes/wouldnt work after time.
i then fixed it with new parts and it did it again..

i learned that i needed to add a new tire with freewheel. and added a front and rear break

 

[Esteban]

I agree.It does sound like coaster brake hub problems . Not hard to rebuild,, &&& I would do it before riding again.

http://www.troubleshooters.com/bicycles/1speed/1speed_overhaul.htm

 

[John-Forrest]

What is a coaster brake?

I'm not sure what a coaster brake is. This particular bike, a WildFire MB26 (preassembled), came with brake pads on rear tire and disc brake on front. Coaster brakes are those old bikes where you brake by turning wheel back, right?

 

[Skyliner70cc]

Sounds like bad freewheel or cassette.

 

[BlueCollarBikes]

I just went on a long trip and there were a lot of lot steep hills. Somewhere along the way, the pedal and pedal arm starting acting like it was coming loose. I went to a bike shop; the guy told me the bike part seems fine but there may be loose bearings in the engine sprocket. Anyway, now the engine is making the bicycle sprocket fly around. I have to hold my feet on the pedals to keep it from flying around at the same speed the engine is turning. Every rotation there is some kind of weird knock.


I'm definitely feeling nervous to ride this like this. Sometimes bike pedal flies around VERY HARD! Like it could break an ankle bone or something. I have to stand on pedal to keep it from moving around.

Anyone have any idea what might be happening? Could have anything to do with clutch not completely disengaging bicycle sprocket/chain?

You will need to rebuild the Rear Hub and bearings on the bicycle.
I would advise NOT to use the bike until this is fixed.
Its not worth the possible Hospital bills.

cheers

BlueCollarBob

 

[arceeguy]

And I wouldn't go back to that bike shop again for repairs. That was a major mis-diagnosis!

 

[JemmaUK]

It sounds like the bearing in the hub has collapsed which means the ball bearings are acting very much like a partially engaged clutch to the pedals... not a good place to be in.

I wouldnt, as has been said, ride it under power although riding with the clutch in should be ok.. its likely you'll need the wheel relaced to new hub and cassette..

Was the bike new when you fitted the motor up to it? or was it an old bike?

Jemma xx

 

[sparky]

The symptoms sound similar to what I've got. A clicking noise when I pedal, and if you pedal while standing up... the crank slips. Doesn't sound exactly the same as my problems, but I'm with Skyliner... it's your freewheel/cassette!!

 

[John-Forrest]

I'm a little confused about the terminology here. I don't have coaster brakes. I'm don't know what a "casette", "hub", or "freewheel" is. (Might be worth considering making a glossary for this forum.) The bicycle and engine are all brand new (well, a few months anyway).

I did go for a local trip today and condition was definitely getting worse - I certainly won't take it out on the road again until I have some idea what is going on here. One thing that is strange is despite this tug-of-war between the bike sprocket/crank/pedal system and what the engine is doing, neither chain has snapped. Also this has just started happening; it wasn't happening orginally.

Upon thinking it over, I think the bike pedal/crank/sprocket system is jammed, and I may have to replace that. One fellow who pulled over to help me when I was out of my area thought something was wrong with ball bearings. Pedal resists going backwards. I checked riding my own regular bicycle (nonmotorized), can pedal backwards and just hold pedal while going downhill. (This may be why coaster brake doesn't work, it can't go backwards.)

Also, I have another thread here about aligning bicycle chain with engine chain. Bicycle chain is too tight/ engine chain tends to be loose. I wonder if that has something to do with this. Since I got this bike, I've had the impression two chain systems seem to compete with one another. This may be a major bug with current motorized bike assemblies.

I'm not very good with mechanical stuff and have a hard time finding mechanic who can handle this. Bike stores seem to have a prejudice against gas engines and motorcycle shops tend to be contemptuous of motorized bicycles (and don't know about the bicycle parts). That's part of the reason I joined this forum.