Idle dies when the bike is warmed up.

[bizak]

The bike keeps its idle fine when its cold, but once I start riding around for more then five minutes the idle just drops down and the bike dies. I have to rev it every time i come to a stop or a red light. Do my carbs need to be synchronized or do I need to adjust the idle? Any information will be very helpful.
Thank You.

[Kreylyn]

The bike keeps its idle fine when its cold, but once I start riding around for more then five minutes the idle just drops down and the bike dies. I have to rev it every time i come to a stop or a red light. Do my carbs need to be synchronized or do I need to adjust the idle? Any information will be very helpful.
Thank You.

Your running rich atm it sounds like for the idle circuit.

What is the A/F screws set at?

Have you checked the floats/float needles are not leaking?

Krey

[bizak]

Actually I'm too scared to mess around with the carbs, so I don't know any of the settings. Is there any charts or pics to show the setting of the carbs?

[Kreylyn]

Do you know any history of the bike? If not, then there are a few things you need to check before actually doing anything.

First, the bike running rich is not normal... it's ussually a lean issue that most people have from varnish gumming up the carbs. The following are possibilities for why it's running rich atm...

1. Previous Owner (PO) was mucking around with the carbs and put in a jet kit or improperly adjusted the carb settings. (least likely, but possible...)

2. The carb floats/float needles stuck or are not preventing the bowls from overflowing, and fuel is being dumped into the engine/was dumped and is now in the oil. When you ride the bike, the fuel rich oil is causing the bike to run rich. This could be compounded by the bike having been left on/run on prime which allows fuel to continue to flow when the bike is not running. It would be very subtle if the petcock was working right, but still present.

What I would suggest you do....

Check the oil, smell for fuel. If you have not already, and it needs anyways... look at an oil change. If it smells of fuel, we need to fix the carbs before putting new oil in btw... but the oil needs to be changed after the carbs are fixed before running/tuning the carbs.

If no fuel in the oil, then I would move on to checking the carbs. You will find it's much easier to do the following by removing the carbs from the bike.

First, before you start... read the manual on how to remove the carbs. Read carbs 101 (wiki link at top, search carbs 101, download pdf, look at pics and read several times).

1. Check for a jetkit installed or not. (pull the caps, look at the needles, pull the bowls... get the size of the main jets, carbs 101 will explain where/how).
2. Verify the air filter setup your using (aftermarket, OEM, airbox or no?)
3. Look to see if the A/F screws have had the covers removed or not. If removed, check the A/F settings (turn them in to seat just barely finger tight... how many full turns did it take?)

This will help us proceed on fixing the issue from there.

Krey

[remix919]

Hate to bring back an old topic, but it seems this was never solved and now I'm having the same problem on my 2005 Katana 750. I had recently bought the bike and at the time it was running really rough, but running, so I towed it back to my house and then took the carbs out and cleaned them real well and then put them back in the bike, but now I'm having the exact same issue as bizak. The bike seems to be mostly stock and the only modification I see is a yoshi slip-on. I am un-sure if the carbs have had a jet kit installed, but the a/f screw covers have been drilled out. I set them to 3 turns out but I'm not sure if that's the stock setting? I would try to follow the wiki link and search, but unfortunately the site seems to be down.