Poorly running

[joshi_88]

I have tried to check many different things and can not figure out what the problem is here. Usually the bike starts without an issue. When getting on the throttle it studders. Sounds like a cylinder is missing to me. After a few minutes of this it gets worse, loses power. Can have the throttle all the way in just to keep it moving. When I come to a stop it is very difficult to keep it running, usually ending up in it stalling out.

When trying to restart it doesnt always start up good, but if I let it sit a few minutes, it will usually start.

Currently what I have done:

1. Change spark plugs, when I took them out, #3 was black, not wet but black dust.

2. Swapped ignition coils, put 3 on 2 and vice versa. When I pulled the plugs, #3 was still dark.

3. It was doing this last year as well, so I took the carbs off and cleaned them this winter. The problem is getting much worse now though.

If anyone has ANY ideas please let me know. I dont know what else to do.

[Kreylyn]

I have tried to check many different things and can not figure out what the problem is here. Usually the bike starts without an issue. When getting on the throttle it studders. Sounds like a cylinder is missing to me. After a few minutes of this it gets worse, loses power. Can have the throttle all the way in just to keep it moving. When I come to a stop it is very difficult to keep it running, usually ending up in it stalling out.

When trying to restart it doesnt always start up good, but if I let it sit a few minutes, it will usually start.

Currently what I have done:

1. Change spark plugs, when I took them out, #3 was black, not wet but black dust.

2. Swapped ignition coils, put 3 on 2 and vice versa. When I pulled the plugs, #3 was still dark.

3. It was doing this last year as well, so I took the carbs off and cleaned them this winter. The problem is getting much worse now though.

If anyone has ANY ideas please let me know. I dont know what else to do.

Sounds like your carbs are running out of gas to me.

Check for stopped up/kinked gas lines, remove any fuel filters (replace only if it came with it stock) check your tank for rust/debris or water, make sure your petcock is working correctly....

Krey

[2003katana]

make sure the air box is on the bike runs like junk without it mine ran poor and i though i had problems till i put the air box on.

[joshi_88]

ok...so i was digging around on my bike for a while tonight and found a few more things that may help to diagnose the problem.

With the air box and gas tank off, looking at the carbs, the plastic shutter door on carb number 3 shakes up and down.

Also there is a fuel mist coming from all of the carbs.

Checked the vacuum on the carbs, it was too sporadic to get a reading.

Does anyone have any ideas how to fix this?

[Kreylyn]

ok...so i was digging around on my bike for a while tonight and found a few more things that may help to diagnose the problem.

With the air box and gas tank off, looking at the carbs, the plastic shutter door on carb number 3 shakes up and down.

Also there is a fuel mist coming from all of the carbs.

Checked the vacuum on the carbs, it was too sporadic to get a reading.

Does anyone have any ideas how to fix this?

Download and print out carbs 101

Pull the carbs, and go through them fully. Pay special attention to the springs in the top, needle settings, and condition of the slides.

Vacuum reading?.... the vacuum is going to be a pumping vacuum, not a steady pull. Any gauge you put on it will need a restrictor, or the needle will bounce so much it's unreadable.

The only concern for vacuum is that there are no leaks, everthing is pluged up correctly, and that the carbs are synced so they are all pulling the same vacuum.

Krey