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Discussion Starter #1
To begin, I have a 1981 suzuki gs 450. I had a friend rebuild the carbs last year because I thought I was having issues that were carb related. I didn't put this on until this spring because I was too busy. I could not get the bike to really start or idle. I checked my ignition coils. The resistances were wrong so I replaced them. Now, the bike is still not running correctly. If I have not tried to start it for a few hours, it will act somewhat normal. It will idle around 1400 rpm for a minute or so, but will only rev up to 3000 when I open the throttle. Eventually, it starts to rev itself back down with the throttle wide open. It'll sit around 900 rpm for about a minute and die. When I start it back up, it takes a little bit and will only sit at ~1000 rpm with the throttle open; again dying fairly soon. If I wait a few more hours to start it, it will start to act kinda normal for a few minutes and progress to the problems previously mentioned. Any help would be greatly appreciated.
 

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Retired twice: Navy and as a govt contractor
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Check and make sure you are getting fuel. Check the lines and filter.
 

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Discussion Starter #3
I can see fuel flowing through the filter so I am assuming it is getting down to the carb bowls.
 

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How old is the fuel in the tank? May just need new fuel. And just because you see fuel in the filter does not mean it's getting to the bowls. Does the carb have a drain plug. If so turn the petcock off, drain it dry, turn it back on and see if more actually gets in. Next would be is the floats allowing enough in so are they set correctly.
 

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Discussion Starter #5
The gas may I have is maybe a month or two old. It runs fine in other motors I have used it in. Also, I drained the bowls of fuel and turned the petcock on. fuel is draining into the bowls so that does not seem to be an issue. I also checked the float heights and they appeared correct.
 

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Retired twice: Navy and as a govt contractor
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Well it takes fuel, air, and fire. What do the plugs like like?
 

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Retired twice: Navy and as a govt contractor
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Air filter?
Vacumn lines
Carb boots tight and not leaking?
 

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Discussion Starter #9
Air filter is new as well. I ordered the exact replacement as what was previously on it. I also took butane around the boots to see if the engine would rev up. I tried it again with break cleaner. Nothing happened so I do not think that there are any leaks there. Vacuum lines is something I don't know if I have checked. The one that goes from the carb to the petcock appears to be working fine with tight seals to the carb and petcock. Are there any other ones?
 

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Retired twice: Navy and as a govt contractor
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Someone else will have to help you with the vacuum lines as I am not that familiar with your bike. The only other thing I can think off is you still have a clogged jet or port
 

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Discussion Starter #11
Okay. Well thank you for your help. I don't know enough about cleaning carbs to really know what else to do. I've read a few different articles and "how to's" on carb cleaning when I cleaned them. None of the ports or jets seemed clogged. Then I, when the issues didn't go away, I sent my carbs to a friend that's been rebuilding them for twenty some years. I may just end up taking it into a shop.
 

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The only other thing I can think of is timing
 
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