QuestionI owe a 2002 Suzuki Katana and last week the bike started to stall and it is getting worse with the time. It stalls mostly when I ease off the throttle on a high RPM, around 5000 or higher but it stall sometimes when I give it throttle hardly. I haven't changed the oil for about 4-5K miles. I used Synthetic and changed filter on my last change. Other than that everything else works perfect.
AnswerI'm not much of a mechanic but it sounds like a fuel problem or ignition problem. You probably need your carbs cleaned and tuned. It could be your pilot jets are clogged due to bad fuel, old fuel, or no fuel filter.
Is the choke mechanism stuck on? If it's been running with the choke on all the time, the plugs are probably gooped up. Remove them and clean them up.
If the choke isn't on, try riding the bike with the choke on to see if anything changes. If running it with the choke on makes it better, your bike is running too lean and the carbs need adjusted. If it doesn't change anything, there may be a problem with the choke.
Pull the spark plugs and check them. They should be light tan in color. If they're whitish, your bike is running too lean. If they're blackish, your bike is running too rich. Either way, if they're not tan, you're probably in for a carb tuning/adjustment/cleaning.
Pat
