Hawthorne weird chain ring bottom bracket problem

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horsefarmer

horsefarmer

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Cleaned and repacked bottom bracket bearings on 1956 Hawthorne (D.P. Harris).
Bike was not ride able when I got it and bearings were dirty and dry.
After reassembly, this is what it does, when you rotate crank in drive direction, the chain ring clears the chain stay on the first rotation, but on the second or third rotation it hits hard and jams up. if you rotate crank opposite direction to brake, (coaster brake needs part right now so crank is free to rotate several turns) - the crank arm strikes the kick stand and jambs after a couple or rotations.
If you reverse rotation of the crank, the chain ring gos back to normal position. It does it with the chain on or off. and if the bearings are adjusted tight or loose. Crank/chain ring is not bent because alignment is perfect first rotation of the crank.
What is going on? did I assemble it wrong? there is no sign (old scratches/gouges) that the crank hit the frame in the past.
 
If the bearings have no play in them before and after, and the sprocket isn't bent and neither are the cranks, then it's a dilemma. If the bearings show looseness afterward, then the lock washer may not be good, or the bearing cups didn't seat properly. I would tear it down and go through each step to see if something is out of place. If it's all good and you still have the problem, check the frame for integrity, maybe the bottom bracket isn't solidly attached to the frame.
 
Thanks, maybe the ball bearings are seated at an angle? It's acting like it's on a thread.
 
That might be it. They have a tendency to get out of the pocket as you tighten the nut. If so, then the cranks will be loose as the bearings drop into the seat. As I tighten the cranks, I'll check for a proper seating of the bearings by rotating the cranks a little to see if it looks too far from the cups. As you put the cranks through the frame, hold it tight up against the drive side if you can, while threading the nut on the other side
 
That may be it! I'm so used to tapered roller bearings self centering - I'll pull it apart and try again. Thanks!
 
I also seat the bearing on the drive side, with the grease to hold it in place, then place the cranks up against it. That side is the one that usually gets out of place.
 
horsefarmer said:
That may be it! I'm so used to tapered roller bearings self centering - I'll pull it apart and try again. Thanks!
Click to expand...

What are you running tapered rolling bearings on? Not trying to "question" you; i'm just curious. I've had some "needle bearing" headsets...
 
At least the bearings are in a cage. Many of the cottered crank bikes I've worked on have loose bearings that fall out all over the place when taken apart. Grease holds them in the cups when it goes back together. They also had loose bearings in the headset and front wheel bearings
 
One of the caged ball bearings was put in backwards in the front hub. kinda sprung the cage and couple balls were loose an fell out - ouch! I put em back in and straightened the cage with needle nose pliers. After re lube, wheel rolls nice now.:grin:
 
Good!
If the cage was too badly tore up, you could go old school on it and use the same bearings without the cage, letting the grease hold them in place.
 

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