im about to change out the bottom end on my motor because on mounting issues and need to remove the piston. any surprises i should be worried about? dont want to break a sensitive part
bicycle engine tear down
- Thread starter Norman
- Start date
look at a couple of the engine tear down stickys they should help you on taking the engine apart.
here's another one to check out.
http://motorbicycling.com/f39/motorized-bicycle-engine-top-end-rebuild-297.html
here's another one to check out.
http://motorbicycling.com/f39/motorized-bicycle-engine-top-end-rebuild-297.html
I have a clutch that has a couple of really rough spots as it spins. I suspect there may be rust, debris or a bad bearing in there but have no way of knowing exactly what the cause is. (the bearings pressed inside the clutch hub as referred to above) I would prefer not to press the unit apart cause it seems like a real pain to get apart and back together...
I am wondering what you guys would suggest I do to try and lubricate these bearings and flush out any debris to try and get them rolling better?
It shouldn't hurt to give a try flushing, yet between Lord Vader's instructions and the way I did it, you have options... 
I like options!
Best
rc
I like options!
Best
rc
hey norm. Ive removed the nut on the sproket side of the clutch shaft and pulled the flower nut and disc and spring off the other side. Im trying to drive the shaft out to the clutch side but its jammed in there even the bearing on the sproket side is beginnning to collapse due to the force of trying to push it across.
The shaft should be jjust sliding thru the bearing on the sproket side ..right?
I cant get the nut off on the clutch side and was planning on doing that once I had it out.
Would that nut be hindering the whole thing coming out?
The shaft should be jjust sliding thru the bearing on the sproket side ..right?
I cant get the nut off on the clutch side and was planning on doing that once I had it out.
Would that nut be hindering the whole thing coming out?
I just pulled a clutch shaft, once you pull the nut and drive sprocket the entire clutch assembly has nothing holding it in place other than a tight fit around bearings. Best thing to do is press the shaft out with something, mine didn't come out easy but came out clean, the chain side bearing stayed in the motor and the clutch side bearing came out with the clutch shaft. The nut under the flower nut and friction plate will not hold the clutch in the motor, it holds the friction plates on the shaft.
If you need to wash out or lube the clutch bearings (2 of them) you can pop off the seal very carefully and do what you need to do. Then replace the seal. These bearings should use seals on both sides as there isn't any other way of getting lubrication, unlike the crankshaft bearings.
Thanks for the input, but I was referring to the bearings that are pressed into the friction plate assembly, not the two main bearings on the clutch shaft.
I have the whole clutch shaft out of the motor, when I spin the big bevel gear it spins rough and there are a couple spots where it hangs pretty hard. I had thought it was bad bearings or rust, but now I notice the bevel gear is a bit loose and can shift around a bit. I can flex it enough to see the bearings, spinning the shaft around to inspect they seem to look pretty good. So I am starting to think something is not true, it seems maybe the friction plate assembly is pressed together unevenly. (loose on one side)
I tried spinning, spraying, flexing to let any debris flow out of there, but nothing changed. At this point I am trying to decide if I should try to press the unit back together evenly, or press it apart for further inspection... Pressing the unit apart is one thing, but pressing the thing back together with all those loose bearings in there seems like it could get a bit frustrating... Has anyone done it, if so, any tips?
Last edited:
Working further with this friction plate I think I have determined the roughness is caused by the bearing ring not being pressed fully in place (bearing ring pictured around c-clamp from your photo for reference). If I hold the plate horizontal (like a dinner plate) and press the bevel gear down as I spin there is no binding, when I turn it vertically like it sits in the engine it binds as I spin it. I see now that the bevel gear has a lot of play, and when it's position shifts is when I get the binding.
Thanks to your picture I have a better grasp of what parts are pressed together here, and I can feel that one side of the bearing ring is not pressed down as far as the other. I'm pretty sure if I press this unit together evenly it will be good to go. Which brings me to the question:
I see your rig to press the friction plate apart, but what do you use to press it back together?
Thanks to your picture I have a better grasp of what parts are pressed together here, and I can feel that one side of the bearing ring is not pressed down as far as the other. I'm pretty sure if I press this unit together evenly it will be good to go. Which brings me to the question:
I see your rig to press the friction plate apart, but what do you use to press it back together?
Attachments
'''with all those loose bearings in there seems like it could get a bit frustrating... Has anyone done it, if so, any tips? '''
Use axle grease .. The thick coagulation of it holds little bearings in place in these situations.
Use axle grease .. The thick coagulation of it holds little bearings in place in these situations.
What I did to lube up all those little bearings was I popped out two pucks so I didnt get grease on those. Then I took a tiny paint brush and dipped it in the grease and then dipped it in the little crack where I removed the pucks and just worked it around till I thought it was good enough.