How to fix rough idle and steady speed on '93 Suzuki Katana?

Question

When idling at a light or stopping at a stop sign the bike may cut out, sometimes, or when taking off in 1st gear it's sluggish and seems to sputter. Once accelerating it's smooth and quick, but that's only after rpm's have gone above 4K. Once highway speed is reached and the throttle is eased back to maintain that speed - it sputters then too. So, it runs, just rough.

Answer 1

It sounds like you need a bit of carb cleaning. Pull the carbs, open the float bowls, remove the pilot jets and clean them up.

The main jets kick in at about 4000 rpm. If it runs rough up to this point, then the symptoms indicate trash in the pilot jets.

Answer 2

Before you do any of the stuff recommended so far, start with the easy stuff first. 9/10 times there is a simple solution to fixing a motorcycle.

You may have some rust or paint chips in your gas tank. This can create temporary blockages in your fuel line.

Remove and empty your gas tank. Turn it upside-down and blast out the innards with a high pressure hose. Let it dry with the cap open. Put it back on the bike and refill with clean fuel.

Answer 3

Synchronize the carbs.
On multi-cylinder bikers, each cylinder wares at different rates than the others.
When that happens, one cylinder may run faster then the others.
The carbs have to be adjusted (synchonised) to slow down the good cylinders and speed up the bad cylinders.
http://www.dansmc.com/MC_repaircourse.htm
Go to - Fuel - Balancing Carburetor

Answer 4

Sounds like the idle and off idle passages in the carbs need cleaning.