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I am totally baffled here. To begin with, I thought I had clogged jets. Idle was erratic, lots of misfiring, and it would often start on one cylinder. I used a lot of Seafoam in the gas, soaked the carbs (on the bike) in Seafoam, and after riding it several hundred miles, it idled just fine. So I thought, ok, the jets are cleaned out. But it doesn't last. Several times after that, the symptoms would reappear after letting it sit for just a few days. If started and ridden every day it would be fine. Since it can't run fine if the jets are plugged, I'm assuming they are not. Can they really get plugged up after sitting for just a few days, even with Seafoam in the gas? Or is there something else going on here? Carb and gas tank venting are fine. It acts exactly like the jets are partly plugged up, until ridden for a while. I'm getting ready to throw in the towel and buy a Honda.
 

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Got any air leaks around the carb boots? And what are the air mixture screws set to? 2 1/2 or so??? I ride mine most every day but since it's cooled off in the morning my idle and low rpm ( <2000 ) is rough. Once I get her hot she's fine. But I do have a fuel seep somewhere on the front carb. One day I'll take them off and try to find it.
 

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Giggity!
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Have you taken the jets out yet & inspected them?
Someone chime in here but I was under the assumption that jets clogged as the engine ran allowing deposits of gunk to collect as the fuel runs thru it, not as the bike sits.

Also, have you removed the fuel petcpck to inspect the screens? You could have sediment collected from the tank building on them or they may have a rip.

As noted above a vacuums leak is also a possible culprit.
It the vent hose going to the right air filter is butted right up against the housing, it can cause odd running conditions.
 

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Jack of all trades
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Is there a strong gas smell? Maybe a stuck float? Is your petcock left on? Check all of these things first, they seem pretty simple but they can all cause some similar problems by flooding out your engine prior to startup.
 

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First off seafoam is garbage!

You need to clean the carbs properly. Remove the carbs from the bike and take them completely apart and clean them with carb cleaner, it's the only way! There can easily be sand or other debris in the bowls or elsewhere and they fall in and out of the jets or other places causing problems.
 

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FREEBIRDS MC CENTRAL NY
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Is there a strong gas smell? Maybe a stuck float? Is your petcock left on? Check all of these things first, they seem pretty simple but they can all cause some similar problems by flooding out your engine prior to startup.
sounds like a stuck float to me
 

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I wanted to clean my carbs, and came across this website:

http://cycles.evanfell.com/2008/09/how-to-clean-a-motorcycle-carburetor-the-right-way/

I pulled the diaphrams out, and put the entire carb assembly and the diaphrams (minus the needle spring & shims) in the boiling lemon juice. I cleaned the bowls and caps with carb cleaner. After reassembly, the bike ran better, and my RPMs actually decreased about 200 - 250 @ 80 mph.
 

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That was a neat read. I will have to try that with my buddies carbs. They are an absolute mess and I will use the boiling lemon juice and see how well it works. Thanks for sharing the link. :smiley_th
 
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