Motorcycle Repair: 83 Honda Nighthawk 650, honda nighthawk 650, internal combustion engines

Question
Hi Falcon,

I have a couple of questions regarding my Honda Nighthawk (83, 650)  Some general fix it types of things.

1.  When I first started it up this spring it was blowin exhaust out of the pipes (that was clearly visible) which is a normal thing when first starting it up, every so often when i fire it up in the morning it still does it any insight as to why?

2.  Every so often it starts relatively rough and i am wondering if maybe the plugs are fouled out, it just seems to run a bit rough.

3.  I saw some previous posts from people who say when they let off the choke it will almost die or will die, mine does that until i ride for about 15 miles or so then it will idle on it's own and you mentioned cleaning the carbs.  I am somewhat mechanically inclined (on cars mainly) so is this something i can do myself, if so could you kinda give me a step by step on how to do it?

Thanks for all your help and your sight has definitely helped me in the past

Answer
Hi Troy.
 Well lets take your questions in order, shall we?

1.  On start-up, many bikes do that.  So far as I am aware, every internal combustion engine does that.  It is caused by a combination of the excess fuel from choking/enriching and the fact that the metal has very small leaks between parts till the heat expands everything into place tightly.

2.  Rough idle is caused by one or more of a few things.  Idle speed set wrong, carbs dirty and sticking, choke stuck partially closed, short in the ignition system, failing ignition components, ignition timing is off and/or valves need to be reset.  Many of these are caught in the scheduled maintainence.

3.  All internal combustion engines are basically the same and are, therefore affected the same way by the same things.
For instance, a race car that has 2 or more carbs has to have those carbs synchronized, just like a bike does, or it won't run at it's best.
Cleaning the carbs is a relatively simple process and what you need for it is just a few cleaning supplies.  You will need a soft bristle toothbrush (I normally use one that I am replacing anyway) or a small nylon detailing brush, pipe cleaners and, of course, carb cleaner.  The brush is for the barrel areas and the pipe cleaners are for the larger areas of the ports (do not force the pipe cleaner through any port.  It should move through with only a small amount of pressure, if any at all).  Do not remove the mixture screws.  Spray through the ports instead for those sections.
Disassembly is fairly simple and as most motorcycle carbs are the same, you can use the repair manual for disassembly.  The exploded diagram in there will be more helpful than any instruction that I can give you.  Besides, the repair manual also has any specs particular to your bike.

Hope that has answered your questions and helped you.
Good luck.
FALCON