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Pop Pop Pop When Pedaling

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Pop Pop Pop When Pedaling

...sometimes I hear that sound too, but is usually while riding through a bad neighborhood, so maybe I'm being shot at???
 
The chainring is AN original part. I had it chromed during restoration. It does have a slight wobble to it...very slight.

I will also add, that I don't feel anything through the pedals when pedaling hard. If I did, I would think chain or rear hub, but I don't feel anything. No chugging or skipping. Just noise, under load.

Thanks and keep the ideas coming guys!

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Is it a pop pop pop or a clack clack clack? "When pedaling hard..."

Are you sure its not your knees? J/k

Check for sharking on the chainrings if no sharking replace the chain and see if it persists, if it goes away its chain stretch causing the chain to climb, the pop is it dropping back into the grooves. If there is sharking on either sprocket same thing, chain climb when pedaling hard. My .02c
 
It sounds like worn drivetrain component(s) to me. From my experience when "new" parts are mixed with old problems can arise that weren't noticed before. The chain, chain ring, and cog wear together, and they do wear out. W/O being able to see your parts, my guess would be that a worn chain is the culprit. Sounds to me like the chain is "stretched" to the point that it is not meshing properly with the teeth on either the cog, new chain ring (more likely), or both, and it's popping when under load. I've ridden many bikes with worn(out) drive trains, and the problem of skipping or popping was not always evident until (greater) pressure was applied to the pedals. I've seen bikes ridden in for flat repairs that have cog teeth that are badly hooked and barely there. The owners never put considerable pressure on the pedals for the problem to manifest, or if they did they backed off so it went away. Wear gets to a point where the solution is to replace chain, cog, and chain ring.
Try pulling the chain away from the chain ring at ~ the 3 o'clock mark. It should not come away from the ring much at all. I've seen them so worn that I could put my finger in between the chain and ring, but the bike rode reasonably okay, because all the parts knew each other well.
You could also remove the chain, count the links, and measure the length. A NOS 56 link 1" x 1/4" chain like what is on your bike measures 55 3/4" end to end w/o the master link.
Is the chain ring made for the 1/4" chain?
I'll bet you a Mexican Coke that chain wear coupled with "new" chain ring is the culprit. We'll settle up on the next Monrovia ride :)
 
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I find on the skip tooth that if the rear cog is shark finned it will cause a grinding popping sound sensation whilst pedaling underload.

Obi wan I thought same, esp what he described about it lessening under more tension, description sounds like a shark finned cog or chain stretch (worn rollers). Checking the pitch of the teeth, and if they look ok replacing the chain to further troubleshoot.
 
Awesome guys! I think you may be right. The chain IS OG and 74 years old. I will measure it and check link spacing and report back. It's not a skip-tooth, but is the wider style chain the Westfield used on their bikes during that era.

It is more of a pop pop...NOT a clack clack or metallic sound.
 
It's not a skip-tooth, but is the wider style chain the Westfield used on their bikes during that era.

Ah, I thought it was 1" but see now it's 1/2".
If I may suggest: try White Lightning on your chain, it doesn't attract dirt like oil.
 
Thank you for cleaning my bike so well.:) Id just go through the bike one part at a time with the chain on tight ( If it tries to ride off then you narrowed the issue down to gears or chain. Then remove the chain & spin the hubs sprocket ect & see if they feel right ..Good luck it a great looking bike.
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Thanks for helping me try to diagnose this guys. I appreciate it. Though it does appear that I have just about every possible part of the drivetrain listed above as the culprit! :confused:;)

Let me see if I can answer a few of the questions above.

- The Chainring is not original. The Chain and Cog/Hub ARE original. (even has the wider Westfield chain)
- The chain is in excellent condition, all rollers turn easily and there are zero binds or issues with the chain (that I can note)
- I will examine for rear shark-finned cog, but I believe it is okay.
- Thank you for the links!
- It's a ND model D hub, hand turning it and such provides a very smooth action. Turns easily and seems to be 'normal.'

I do feel like it was the BB being too tight. Now with the looser/lighter pre-load almost all of the popping is gone, but I need to give her a better ride test to see.

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if your chain has no slack it could cause this noise ,as it will bind on a re-chromes ring till it wears in . nice bike
 
Is the rear sprocket the wider 3/16 width for the wide 1/2" pitch chain? Is the chain in line? Did you replace the bottom bracket bearings? What about the small outer bearing in the rear sprocket?
 
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