I have a 02 busa with 4300 miles with 2 in 1 exhaust and headers. I just bought the bike and the previous owner didn't maintained it right. It kept stalling out at first when I came to stops and it runs rich, black smoke. I put new gas, air filter is fine. Owner said he just replaced the spark plugs but they were fouled by too much gas. Few vacuum hoses were disconnected as well. I replaced the plugs and it ran great for 20 miles and no went back to rough acceleration again. Idle is set at 1800. It fires right up and idlees fine but the engine will studded at random on hard acceleration but does fine on normal riding. It will studded and then kick in and then will studded again. Happens at random. What's my cause? Exhaust?. The bike only has 4000 miles but only ridden 1000 miles in the last 9 years by the previous owner
Answers & Comments
Verified answer
"Few vacuum hoses were disconnected as well."
Before you do anything, put all hoses back to standard.
Hayabusa Spark Plugs
"Few vacuum hoses were disconnected as well." If the hoses are still out you need to put em back in. Take the bike to a shop that does dyno tuning and have them remap the ECU. That should fix the rich gas smell. The other issue with running rich is a bad O2 sensor but the check engine light would come on if that were the case. Put some fuel line cleaner in the gas tank as well.
2002 Hayabusa
I think you mean "stutter", not studded. Is your bike fuel injected of does it have carbs? If the latter, there's no such thing as remapping the ECU or it having an O2 sensor. Pretty hard to make any suggestions not knowing which it has. If it has carbs and you can start it without choke and it runs fine while cold, but worse as it heats up, that sounds like someone has dinked with the carbs. If fuel injected, there's several sensors it could be. And the idle at 1800 rpm is pretty fast, it should be able to idle much slower, like 1,000-1,200 rpm.
You need to put the bike back to its original configuration. If your fuel injection light comes on, you can place a jumper wire across diagnostic plug that is located under the passenger seat. After placing jumper wire , turn your ignition to on position and it will flash a code. You can look up the code here http://www.hayabusa.org/forum/maintenance-do-yours...