OK so for the past 2 or 3 months now my f4 has been running less than par. Its getting worse and worse by the week. Main symptoms are its very hesitent and rough under about 3500 rpms. After that she runs like new, noproblems. From a stop, I can feather her up and not get any skips, but lets say I'm in a parking lot, its embarrassing hearing nothing but spuddering like she's going to stall out. Its not so much noticeable when its cold, the problem is mail after she's been warmed up a for about 15 minutes then it gets worse and worse until I either have to stop or get on the freeway (as long as she's cool, she's cool) . Not overheating though. I have checked my plugs and air filter thus far and no problems there. I have a modded pipe with no baffles, some of my friends say it could be that, but I doubt it since its been on there since I bought the bike, and I have had no problems with it. I have two videos, one showing the hesitation in the throttle, and the other showing the rpms at idle (very jumpy) although I can't post them from my tablet, if you have any ideas message me I'll be more than happy to send the video somehow. Thanks guys! Also I'm not a very free person, so i really don't have time to have my bike in pieces looking for the culprit, I just want to know what to try first in my process of elimination.

 

Also forgot to mention, last week I started it with the choke on cuz it was really cold, and as soon as I turned the choke off it misfired a cylinder all the way to work, (5 mi) but hasn't since then. Got white smoke for two days after that after 5 minutes of running, then it went away, it didn't smell sweet so i don't think its anything too major

 

I believe that's the last year before the bikes went to fuel-injection.

If so, it sounds like the carbs have fouling in the low-speed/idle
circuit. You can try running some carb-cleaner through the
next couple of tanks of gas.

If that doesn't work, you may need to pull the carbs and do a
thorough cleaning of the idle jets.

Another (less likely) possibility is the r/r is beginning to fail.
With that scenerio, the current to the ignition circuit is being
choked as the r/r heats up and the ignition coils aren't getting
sufficent voltage.

Ern

 

I think that the two areas that MadHattr059 mentions are most likely correct. Both of these areas will cause symptoms similar to what you're describing. Another item that could be tossed in for good measure is the battery. However you'd probably notice harder starting with a weak battery. It's easy enough to check the connections to the R/R. Make sure they're good and snug. Check for over heating of the connector.

 

Update: ran some techron fuel cleaner (not the gas) one treatment, and she's running absolutely perfect, EXCEPT I parked it yesterday to change for work and started her up, and she misfired, rode to work, less than a mile, and when I left work, she wouldn't start, low battery, I pushed started and no misfire.....??? Ran her for a good 2 hour ride today, absolutely nothing wrong. So now that my carbs are running better, my money is electrical, probably r/r. Monday I'm taking the bike to my buddies house (gearhead) and were going to test I the r/r as well as the coils, plug wires ect...thanks for replies y'all, I'll let you know what hapenes come Monday!

 

OK so we checked the battery and r/r everything checked out like she just came off the showroom floor. I'm stumped now. My carbs are running great now that I treated her with some cleaner and all my electrical check out thus far. Maybe just a bad start? But it has misfired twice...never since the last time which was a week ago now almost and I have opened her up on the freeway just to make sure....at this point I think only time will tell. I might go thousands of miles and it never misfires again, or it could and I'll have to dig deeper....but at this point I want to say if she ain't broke, don't fix her, because she's been running better than when I picked her up after the fuel cleaner (but remember she misfired and wouldn't start AFTER the treatment)

 

Fuel cleaner additives are not an instant fix.
Run a couple of tanks, see where that gets you.
Hopefully, this will clear up the issue, and happiness will desend upon you.

Ern