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Discussion Starter #121
Well this is going to be fun! I adjusted the springs to just barely engaged at rest, and went on another ride. The surging was gone! But the hanging up at 3000rpm was back. 😂

Unless anyone has a better idea, my next course of action is to carefully and gradually increase the tension on the springs until I reach a happy medium... It's going to be a process because I have to readjust ignition timing each time, but I've marked my position on the contact breaker plate so that helps a bit.
 

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Discussion Starter #123
I tried twice more, making tiny changes to tension of the springs, so that they were just beginning to stretch when the weights started to move. Then I tried perfecting it again. I think it feels pretty perfect! But I've now reached a point where at 3000rpm the engine revs up too quickly, and it just slightly hangs up at that same rpm when I release the throttle.
Going to wait for the new carb boots to come in. I'm starting to wonder if it is some sort of air leak after all...
 

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Discussion Starter #124
New carb boots installed. Definitely made the idle and revving 'cleaner.' Still can't operate throttle smoothly. Engine revs up at 3000 rpm. Tried adjusting the springs two more times and I've arrived at the best situation I can.

Here's a video of me operating the throttle to demonstrate how after slowly opening the throttle, it sort of runs away after 3000 rpm, shooting up to 4500 and then operates smoothly again. I haven't cleaned up the carb yet. Is there anything else I might do before I clean the carb? Is this even a problem?!? Maybe I'm tripping up on something normal with these bikes, it's just this little goldie is the only one I've ever ridden.

Here's a video I took of the issue.
 

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Discussion Starter #125
Just a note on the video: I'm opening the throttle very slowly and steadily so that you can see when it jumps up on its own accord.
 

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I'm a little puzzled. I expected it to rise more quickly and more dramatically based on your description. I see what you mean but not knowing the actual hands-on level of sensitivity in person, it's hard to be sure if it's that out of the ordinary.
 

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Out of curiosity have you cleaned the weight posts and weight holes so there's no friction that might be causing a weight to temporarily stick.
 

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Discussion Starter #128
Tom - I, too, am puzzled. If my descriptions were exaggerated it may be the result of some hypochondria from the saga of this build.

Jim - I haven't done that yet. The advance seems to have a good action and no hang-ups. But what would you recommend - disassemble and clean or just spray some carb-cleaner in there?

Today I went on my first real ride on this build (Scappoose-Mist-Jewell-26-Vernonia-Scappoose. If you ever want to do a great ride relatively close to home, that's an incredible one, Jim). The time on the bike allowed me to try and troubleshoot exactly what's going on. Now I think instead of an overactive upper end of rpms, the engine may be actually hanging up at the lower rpms and then at 3000 it finally catches. While riding, I had very little power in the low end. In fact, I had to keep the rpms up above 3000 to ride. Above 3000 rpm the bike felt pretty good. Not perfect, but rideable and powerful. It wasn't a problem riding country roads, but back in the city it was a little awkward. My personal next step is to pull the carborators, clean them, and carefully set them back up so I can have a blank slate on that end. My carb knowledge is half-baked, but I seem to remember that the carb uses different jets at different engine speeds. Maybe a jet used in the 1000-3000 range is clogged up?
 

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Take the advance mechanism out and apart. Take photo's! Polish the pivot pins and the pin bores of the weights. Use a light oil, 3in1 or similar, to lube the pivots. Without the springs move each weight thru it's entire travel feeling for any drag. If you get drag then the weight is touching something it shouldn't, figure that out and fix.
Next insert the points cam and work the advance looking for any sort of bind on the ears that fit together, should be perfectly smooth.
Now reassemble w/springs and recheck that the weights are moving freely and snapping back like they should. If all that's good the put back in and time the engine. Hopefully this will help.
At low rpm you're looking at the idle and primary main fuel circuits. Check things like the tiny transition ports on the throat floor at the throttle plate by spraying carb cleaner in thru the mixture needle hole.
 

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These springs: Century Springs #B3-5 fit the timing advance mechanism .No adjusting necessary . I found this info on this site in a previous post. I put them in my bike because my idle would hang up . fixed problem . hope this helps
 

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Discussion Starter #132
Thanks for the suggestions Jim. I'm going to try what you recommend tomorrow and will report!

Kanga 2, incredible resource! I am awed by whoever figured that one out. If the engine hangs up after tomorrow's tinkering, I will gladly pay $30 for two springs.
 

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Hi ethano I just went to their website in Oz and ordered 4 Pretty sure Century Springs is a U S of A company this is what I paid Aussie $ Been interesting reading about the rebuilding of your motor.

4 x #B3-5 extension springs $5.10ea
 

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Now if we can get members with different models to measure their advance springs we could have a new resource
 

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Discussion Starter #135
Mixture needle.

310395


Upper left is what I just pulled out of the left carb, along with a bunch of metal shavings. Bent tip!
Bottom right from a spare carb. Planning on installing with spring and new o-ring.
Spare and all the rest of pieces in carb dip. Maybe this is the culprit. Going to tackle the right carb next.
 

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Discussion Starter #136
I’m thinking of trying to swap in the body of my spare carb because I’m worried that the metal shavings that came out of the mixture screw hole might be indicator that something is damaged. I’m on the second soak in the chem dip because it was pretty gunked up.
My question: Is swapping out the carb body ok if I keep all the other components the same? Don’t want to inadvertently open a can of worms.
 
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