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I have a 78' CX500 and I think its running rich. It idles at around 3000rpm. There is a small hole in the tailpipe from rust and I can hear a false backfire coming from that spot, I think its unburned fuel. The other night I smelled a little gas as well when it was idling for a few minutes. Does this sound like its running rich? if so, is it a fix that I can do myself or should I take it in to a mechanic. I'm pretty new to motorcycles but I am fairly mechanically inclined, so I think I can do it, i just don't know where to start. It seems like there should just be a screw that I adjust but i wanted to get some advice here before I started anything. Any advice and or pictures would be great. Thank you



-photocodo
 

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Hi Photo, your idle is way too fast. It should be 1100. Have you gone through the carbs? Sounds to me that you could have a sticky float needle giving you the symptoms. There are lots of posts in here with pics for servicing your carbs. If you are inclined you can do it yourself. I'd get a service manual (or better for this instance) pick up Larrys cx carb rebuild book-you'll have fun doing it!

Your avatar reminds me of the new swamp people show. You got a gator lying on the bottom of your boat in that pic?
 

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Discussion Starter · #3 ·
Hi Photo, your idle is way too fast. It should be 1100. Have you gone through the carbs? Sounds to me that you could have a sticky float needle giving you the symptoms. There are lots of posts in here with pics for servicing your carbs. If you are inclined you can do it yourself. I'd get a service manual (or better for this instance) pick up Larrys cx carb rebuild book-you'll have fun doing it!

Your avatar reminds me of the new swamp people show. You got a gator lying on the bottom of your boat in that pic?


Haha, no gator but we were in the process of chasing 4 adult Orcas up in Canada. We were in a 7ft fiberglass skiff so it was a little scary but always an adventure. Thanks for the advice, I might see if I can buy an extra set of carbs and rebuild them since my bike is my primary mode of transportation. Does anyone know a good price for a set of carbs? Or better yet, does anyone have a spare set they would sell?
 

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I would advise you to plan on fixing your motorcycle yourself. These are old bikes and many motorcycle mechanics don't know them like new bikes. These are also straight forward bikes to fix even if you're new to wrenching.
 

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I agree with KjellM - you can fix the bike yourself even if you're not experienced.



First of all, your idle is way too high. It is supposed to be 1200 rpm but some of us have it set a bit higher. Let's call it 1600 rpm max idle.



To determine "rich" you have to pull out the spark plugs and evaluate the color. If your plugs are black, then yes, you're running rich.



Back to carbs, get your idle down and then synchronize the carbs. Each cylinder should do half the work -- you don't want one cylinder pulling harder than the other. An easy check is to run the bike on only one cylinder. Pull off the right spark plug wire and start the bike. Note the rpm and then run only the other cylinder. Rpm on each side should be exactly the same. If they're not, then adjust the screw on the spring loaded linkage that's between the two carbs until both cylinders run at exactly the same rpm.
 
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