I am a long time forum reader, but I almost never post. Mostly because I have only owned a bike for 2 years and have a lot to learn. Anyways...
I recently wanted to clean my carb jets on my 02' ZX6R. I am fairly mechanically inclined and I have slowly been stepping up the level of maintenance tasks. Following a great post on these forums, I took my carbs off, cleaned the jets and float needles, and then reassembled everything.
This is where the first problem comes in. When I was putting back on the airbox, I accidently screwed a long screw into where a short screw was supposed to go. This ended up hitting the plastic air vent T connection for the carbs. It may have cracked it, I can't tell for sure.
Now onto the symptom of something wrong. I ignored the cracked air vent, for the moment, and continued assembling everything. Mainly because I depend on the bike to get to work. When I got everything back together, it started up right away and seemed to idle and rev great. However, when I went for my first ride I ran into some problems. After accelerating to 9000 RPMS or so, then letting go of the throttle, the bike would very slowly rev down. Before this maintenance, the engine would quickly slow the bike if I let off the throttle. Also now, with the clutch pulled it, if I rev up the bike and let go of the throttle, it slowly revs down, and then settles at 3000 RPMs. I can't get it to idle any lower. If I back out the idle screw any farther, the throttle doesn't rest against the idle screw.
I am sure I did must have done something wrong when I put it back together. Anyone have suggestions of what to look at? Could this problem be due to a cracked carb air vent line? I also changed the spark plugs and cleaned the air filter.
I am a long time forum reader, but I almost never post. Mostly because I have only owned a bike for 2 years and have a lot to learn. Anyways...
I recently wanted to clean my carb jets on my 02' ZX6R. I am fairly mechanically inclined and I have slowly been stepping up the level of maintenance tasks. Following a great post on these forums, I took my carbs off, cleaned the jets and float needles, and then reassembled everything.
This is where the first problem comes in. When I was putting back on the airbox, I accidently screwed a long screw into where a short screw was supposed to go. This ended up hitting the plastic air vent T connection for the carbs. It may have cracked it, I can't tell for sure.
Now onto the symptom of something wrong. I ignored the cracked air vent, for the moment, and continued assembling everything. Mainly because I depend on the bike to get to work. When I got everything back together, it started up right away and seemed to idle and rev great. However, when I went for my first ride I ran into some problems. After accelerating to 9000 RPMS or so, then letting go of the throttle, the bike would very slowly rev down. Before this maintenance, the engine would quickly slow the bike if I let off the throttle. Also now, with the clutch pulled it, if I rev up the bike and let go of the throttle, it slowly revs down, and then settles at 3000 RPMs. I can't get it to idle any lower. If I back out the idle screw any farther, the throttle doesn't rest against the idle screw.
I am sure I did must have done something wrong when I put it back together. Anyone have suggestions of what to look at? Could this problem be due to a cracked carb air vent line? I also changed the spark plugs and cleaned the air filter.
Any help would be greatly appreciated! Thanks!
Take it apart and check all the connections, you may have an air leak somewhere. If you are talking about the air vent i think you are talking about i don't think it would cause this issue if it was cracked as i believe you are refering to what basically amounts to an air pressure equalizer for the carbs and ram air system.
pics would be helpful maybe...
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Is the vent hose connected to the petcock? There's the main fuel feed, and then a little vacuum hose that comes off the petcock side and goes into the 2nd carb. I missed that once and had similar symptoms. that one is easy to check.
Did you mess with the idle screw at all?
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Last edited by cookiebug79; 01-16-2013 at 01:48 AM.
I will check the vacuum hose connection to the petcock when I get home from work. I thought I connected all the correct hoses, but now I don't trust anything I did.
If the vacuum hose looks fine, I will take the carbs off and check the rubber boots and other vacuum lines. It ran fine before this, so there has got to be an assembly problem somewhere...
Thanks for the suggestions of things to look for. I will let you know how it goes, and supply some pics.
Take it apart and check all the connections, you may have an air leak somewhere. If you are talking about the air vent i think you are talking about i don't think it would cause this issue if it was cracked as i believe you are refering to what basically amounts to an air pressure equalizer for the carbs and ram air system.
pics would be helpful maybe...
Maybe I am misunderstanding carbs, but wouldn't the bike run lean if there is an air leak? Doesn't that mean it will not idle well?
And yes, I am refering to the air pressure equalizer for the carbs. Atleast I think that is what it does from doing some research.
I also had the issue where the little plastic float valve would stick. It would idle high for a while until I played with the throttle and then it would drop way low. That doesn't quite sound like your issue, but it could be that.
If it's a vacuum leak, you can spray carb cleaner around areas of the hoses while it's running. (Don't spray it on too much plastic because it will degrade.) If your idle increases momentarily you know what area to look in. Also, the bike won't run well if the airbox and air filter aren't fully installed properly.
Keep us posted!
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When you turn your bike on, does it return the favor?
So now for some resolution to the problem... hopefully. Today I took the carbs back off the bike to see what the problem was. After getting them off and on my work bench I saw what I assume was the problem. A piece of blue shop rag was stuck in the throttle shutter for one of the carbs. This prevented the shutter from closing all the way. Since the shutter operators are all connected, it probably prevented all of them from closing. Hence the high idle. Also, I assume it gummed up the throttle response a tad.
After removing the shop rag, cleaning a bit more, I reassembled everything and went for a drive. I just rode around the neighborhood, but all seemed well again. Seemed a little better than before I took the carbs off. I will go for a freeway drive later and let you all know if I find any problems.
I will try not be such an idiot next time. I usually use shop rags to cover openings to prevent dirt, dust, and tools falling in. I guess I just forgot to remove a piece? Oh well... I guess all's well that ends well?
High idle after carb clean
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