My 1987 LT 230 started misfiring and running rough just recently.  Also, for the past few years the lights work but are very dim.  They will flicker bright for the last few cranks when I shut the motor down.  I have cleaned the carb and tried a new battery, but this did not help.  I need help diagnosing these problems - the local dealer is no help and just wants my money (which I have none).

Thanks  

sounds like you may have some rust on the stator contacts and magneto.
you can remedy this by using a very fine sandpaper and cleaning the rust off.

other than that the stator may be weak and need replacing.  

The lighting problem is probally your voltage regulator. It seems to be a common problem on the suzuki's. I have the same problem with my 1987 suzuki lt-f 230. My recommendation would be to get the clymer manual #M475 for that model if you do not have it yet. There is directions in there to diagnose this problem. as for purchacing a new voltage regulator I recommend going to RegulatorRectifier.com part #10-240. My boss has the same machine and had the same problem as well and this part fixed the problem. We did have to switch the end on the ground wire because the ltf230 and the lt-f 230 have different style ground connectors.  

Thanks for the tips.  I have just brought the machine back from up north (Michigan) so I can begin to work on it.  I plan to do a full restoration and maybe some mod's this Winter with my son.

I will let you know how it works out.  

replace the starter solenoid to fix the lighting issue, as for the poor running. just go through everything one day, make sure to clean all jets and ports, check the air filter. the works. if nothing changes. there is always a dealer