A Little Help Please! Missfire Issue.

[dandraven]

So, I have a 06 busa. recently it started running a little rough. I checked the plugs and they indicated a slight rich condition but also had an excessive gap, so I replaced them. the bike still runs as if it is missing on 1 cylinder but if I raise the tank within 15-20 seconds it smooths out and runs fine. When I put the tank down 15-20 seconds later the "missfire" returns. I have checked for vacuum leaks and pinched fuel line, dont see an indication of any. The tank is 3/4 full.
Any thoughts or suggestions?

 

[Ham]

i would remove the tank and check the pump and filter.

 

[dadofthree]

Probably a fuel line, that's all that's changing with the raising of the tank. If they're the original lines you might need to replace them.

 

[Draven69]

thanks for the suggestions, I'm going to remove the tank, check the pump and filter when I get off of work tonight. If it is a pump issue Im looking at a AEM high flow replacement. (part # 50-1000) Has anyone replaced their pump with an AEM unit?

 

[dandraven]

well I took the tank off, drained the fuel and noticed some sand. We pulled the fuel pump out and cleaned the filter (was dirty but not overly so) reassembled everything. Put a gallon of ethanol free 91 in it and it started right up smooth as silk. gonna run her tomorrow and let you all know the outcome.

 

[Draven69]

well took the bike out and put about 20 miles down but everything seems to be working fine, going to put in a hundred or so Sunday. thanks for the recommendations.