Motorcycle Repair: Katana 750 - idling, accelerator cable, throttle cable

Question
Hi, Chris.

I'm not able to reduce the idle speed of my 1993 Katana 750.

The engine speed is about 4000 rpm. If I pull the choke lever all the way, the speed reduces to about 3500 rpm, and hence I dont think its a problem with the choke (I might be wrong here). Turning the idle screw all the way to the left (minimum idle speed) doesn't help at all. Turning it to the right increases the revs further. The adjustment for the accelerator cable is set to a position where the revs would be minimum.

Could you please help me with this?

Many thanks.

Gopinath.


Answer
Hi Gopinath.
 What is your idle speed supposed to be at on that bike?  Around 1500 or so, right?

 How much freeplay is in your throttle cable?  You should have about a quarter inch of turn before the throttle actually engages.  Anything less and you could have a problem.

 Also, it could be that one or more of the actual choke mechanisms is sticking.

 Remember that each carb has it's own choke mechanism and that cable connects to all four of them together through a linkage assembly.

 If part of the linkage has loosened up, then all of the chokes will not work together or one or more could come loose and stick either open or closed.  This would case the bike to over rev as well as run very rich once the bike is warmed up.

Check your spark plugs.  See if any are blackened more than the others.  That is a good indicator as to which, if any of the chokes are sticking closed.

Let me know what you find and we can proceed from there if needed.
Good luck.
FALCON