help my busa

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hello i have a 03 busa with a rebuilt motor having problems the bike fells like its not smooth and hesitating dose not sound like its missing i checked the plugs and the #4 plug is black 1 2 3 look good i did notice the mass air sensor on back of the air box looks like it was broken and glued back together i also had the injectors and air cleaner cleaned i'am running a full muzzy header w/ power commander
 
no codes i was thinking the same about the injectors i had them cleaned but did not have the synced thanks will try
 
pull your power commander and see how it runs, you might find its the actual problem. Also like Big E said have you had the throttle bodies sync'd, also how many miles are on it, you could have a valve shim out of spec and causing a bad running condition on that cylinder. Or a combo of all of the above
 
hello i have a 03 busa with a rebuilt motor having problems the bike fells like its not smooth and hesitating dose not sound like its missing i checked the plugs and the #4 plug is black 1 2 3 look good i did notice the mass air sensor on back of the air box looks like it was broken and glued back together i also had the injectors and air cleaner cleaned i'am running a full muzzy header w/ power commander

Were the injectors cleaned and calibrated?
 
Definitely try syncing the tb's, i generally do mine once a year atleast just to check. smooth things out alot when they're all running the same!
 
Plug #4 is your clue - you need to figure this our first. Bad connection to the plug, or defective coil? Injector sprays too much? (unlikely). First, clean #4 plug or put a new one, and make sure it's gapped at 0.8 mm. Then, I'd swap #3 plug wire with #4 plug wire. See what happens. If #3 plug becomes bad, then it's the plug wire. If it's stays the same, you may have a bad connection from ECU to #4 plug.

Pulling PC out is a good idea, too. You can do all of this at the same time, and if the problem disappears, then you can put one item at a time back to see what's causing the problem. Could be as simple as the plug wire is not seating all the way, and the plug does not fire all the time.

TB sync being off may be noticeable at idle, but is less noticeable with more throttle opening. If injector was clogged, you wouldn't get too much fuel, and the plug wouldn't be black (from unburned fuel).

What's the deal with the punctuation? It's annoying to read.

Let us know how it goes. Don't just disappear. Oh, and :welcome:
 
Plug #4 is your clue - you need to figure this our first. Bad connection to the plug, or defective coil? Injector sprays too much? (unlikely). First, clean #4 plug or put a new one, and make sure it's gapped at 0.8 mm. Then, I'd swap #3 plug wire with #4 plug wire. See what happens. If #3 plug becomes bad, then it's the plug wire. If it's stays the same, you may have a bad connection from ECU to #4 plug.



Are you talking about swapping the actual coils or telling him to take the #3 connector and put it on #4 connector and vice versus? Wouldn't this screw the timing up since 1&4 - 2&3 fire together?
 
Are you talking about swapping the actual coils or telling him to take the #3 connector and put it on #4 connector and vice versus? Wouldn't this screw the timing up since 1&4 - 2&3 fire together?

You are right to clarify: swapping the entire plug wire (both ends), not just one end which goes to the plug, otherwise it will screw up timing.
 
as stated swap the coil sticks around as well as the plug and see if the problem moves.

As for the sensor, that can be a problem, if its not reading the correct vacuum, the bike will run rough!

Also what sensor is it,, is the one the mounts to the air box?

Dont have a heart attack when you look it up, for a price!
 
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