99 Bandit 1200 acts like its not getting fuel second gear and above

[brainsick]

Hello all,
I've been bangin my head against the wall with my 99' bandit 1200. The bike idles, revs, and runs perfect until about half way through second gear and above then it breaks up/stumbles and acts as if its not getting fuel, can only run about 1/4 throttle.... Push the clutch in for a second and I can start back off for a couple more seconds than it breaks up again.. First gear will lite the tire off and second will start to pull then nothing. The kicker is the bike ran perfect about 2 weeks ago, all I did was pull the tank and body panels off, painted them, reassembled and went to take it for a ride and nothing but problems... Since the issue arrose I thouroghly went through the carbs cleaning all jets and blew through all journals, checked float heights, rebuilt the petcock, checked for any vacuum/intake leaks, checked for venting issues, no issues with debree in the tank, cleaned and checked every electrical connection/grounds, new spark plugs, checked for shorts in the plug wires, I even tried gutting the petcock and installed an inline valve thinking that maybe the new diaphragm was defective but no improvements and is flowing fuel... Has anyone experienced this type of issue? Like i said it will pull hard until after second gear....??? Any help would be much appreciated. Thanks

[bullet5]

Now I've not come across that one before. With it reving perfectly in 1st that decreases the chance of it being fuel related, however as that is the main area you've been looking that does strike as odd. What sort of temps/humidity are you riding in?  If you're UK based then it could be carb icing, as that would be causing the bike to stutter (sound as though it's missfiring), and you would slowly be able to use less and less of your rev range. Once you left the bike off for a few mins you would be able to rev freely again for a little while, however this normally affects all gears, not just 2nd and above.

Hopefully someone else will have experienced your problems themselves, and be more knowledgeable than myself.

All the best,
Bullet5.

[brainsick]

I just wanted to add that I swapped the coils with a known good set and still the same issue.... At the moment our temps have been between 30-60 degress F with very little humidity, so icing wouldn't be an issue, thank you for the response though bullet5.

[LowRyter]

any chance of an air leak?  (my bike stumbles in heavy rain and I have to keep the rpms up)

Checked plus & wires?

Do you rev it that hard in the higher gears?  Typically there isn't enough room on the road to do that.

[brainsick]

Definately no air or vacuum leaks, triple checked that, I replaced the plugs and checked the wires by misting some water onto them and no shorts, I cant get the bike passed 1/4 throttle in any other gear than 1st and if Im lucky 2nd but then its just acting like its starving for fuel.... First time I've ever delt with this kind of issue... I want to add also I swapped out the pulse generator with another known good one thinking maybe its not getting the timing and still the same issue... I'm beginning to believe my CDI is the culperate....??? Any other ideas would be great. Thanks

[brainsick]

Another addition to this seemingly impossible mission to trouble shoot this issue, I just swapped out my cdi box with a known good one and the bike has no improvements, still the same issue...... I'm running out of ideas, does anyone else have any words of wisdom????

[pmackie]

How did the plugs look when you replaced them? How do they look now?

You may have checked these, but here are some things you haven't mentioned:

1. Check the airbox and air filter. Make sure it's clean, and that you're not building up anything in the bottom of the air box.

2. Try riding with the gas cap open, to eliminate any chance of a venting issue.

3. Make sure the Choke (enriching circuit) is fully closed.

4. Remove the in-line filter completely to make sure there is no restriction in the supply.

[smooth operator]

How did the plugs look when you replaced them? How do they look now?

You may have checked these, but here are some things you haven't mentioned:

1. Check the airbox and air filter. Make sure it's clean, and that you're not building up anything in the bottom of the air box.

2. Try riding with the gas cap open, to eliminate any chance of a venting issue.

3. Make sure the Choke (enriching circuit) is fully closed.

4. Remove the in-line filter completely to make sure there is no restriction in the supply.

[smooth operator]

  I know you said  checked it, but I still think it has to do with some kind of vacuum issue with the gas tank.I don't know if opening up the cap would make any difference,but it just seems like I remember something similar years ago . Don't remember if it was on this site or maybe Bandits R US ? Make sure the vent hose isn't kinked,and I think the issues that I remember reading about, might have been in cold weather.( My bike LOVES the cold crisp air.) Don't know why that would make a difference. But I would check plugs. If they are rich, then that would not be it. And lighter if they might be starving for fuel.
  Granted, I'm a tile setter not a bike Tech.But for some reason I think your running out of fuel and might be a simple fix. Just have to find it first.  Dan

[rider123]

I would agree with the general statements in this post. I highly doubt you did something catastrophic. I would recomend lifting the tank again and check to see if a vacuum or fuel line got pinched in the process. Let us know how you make out. The reason that your bike or any for that matter likes colder air is because the oxygen molecules are more dense which gives better combustion, which equals more power....enjoy it   Although it could be that your running a bit rich and the colder air will lean it out a bit. See how you make out. If not you can PM me and I'll give you my phone number and we can go through the checklist.

[brainsick]

Pmackie,
The plugs removed and the current new plugs are a perfect golden brown, Air filters are clean, tried running with the cap open same issue, the choke is working and disabled, and there's currently no inline filter or blockages in the fuel line.
Thank you for the help!

[brainsick]

Smooth operator,
I don't know how it could be vacuum issue because everything is checking out.. There is only one fuel feed, one vacuum line, and one tank vent line and they are all free and clear. The tank is venting when I remove it and shake the fuel around , also there is no change in flow when I turn the petcock to prime and open or close the gas cap. As far as being cold the temperatures are currently around 48 which is right around the same temps as it was the last time I rode it with no issues... I really hope this is a simple stupid fix, but at the moment I'm at a loss for words.........
Thank you for your help!

[smooth operator]

  I just like to try all the easiest things 1st. Hopefully it will still be a easy fix,the hard part is finding the problem. You have already been doing that,and now I'm scratching my head too. After I posted I pulled my tank, (98 B12) and just took a look to see if I can think of anything.
I wanted to check over my steering dampener mounts anyway.Make sure all fasteners were secure and a visual check over everything.(found a loose bolt that mounts to the clamp on my right fork tube for the dampener. )
  So now, without going back over all the older post, I'm thinking carb.
 Everything clean,all O- rings are good and present. Check all jets are clean,needles move freely. I guess just go over the carbs and hope you find something.   :beers:Dan

[brainsick]

I would like to add some information about the bike to see if maybe I'm overlooking something because I can't figure out this issue.. It has k&n pod filters, 150 main jet, 35 pilot, needles are set on the 3rd clip down from the top, custom exhaust, air mixture screws are set at 3 turns out, and it has a + 5 degree timing gear on it.

[smooth operator]

I would like to add some information about the bike to see if maybe I'm overlooking something because I can't figure out this issue.. It has k&n pod filters, 150 main jet, 35 pilot, needles are set on the 3rd clip down from the top, custom exhaust, air mixture screws are set at 3 turns out, and it has a + 5 degree timing gear on it.
  I have the same set up except I have 32.5 pilots and my needles (hole shot needles) are 2nd notch down.
  Wasn't your bike running fine before with the set up you all ready have?