Fluxtuating Idle.(did I spell that right)?

I have had my Honda Shadow for a week now and have had no problems. It runs well but the only problem I have noticed is the idle when I am stopped goes up and down, up and down. About 100-200 rpms or so. Does this mean I just do a carb sync or could it be something more simple?

I have thought about trying a new set of plugs. I dont think they have ever been changed. The man I bought the bike from was'nt very mechanically inclined. Could putting in a new set of spark plugs be worth a try?

 

You suspect the plugs haven't been changed after 25K miles??

Replace them.

 

I know they have had to at least been changed once or the bike would probably not run at all. I am going to try that, I was just wandering if it could be carb sync or something else.

 

It's more than likely carb related, but a new set of plugs will not hurt.

At the very least you get to look at the old plugs and see how the mixture looks.

 

Ok. I just checked them out. The mixture is right on all plugs. The plugs are the wrong heat range though. The plugs that are in the bike are for high speed riding. No wander it cruises so nicely and idles crazy. Also they are the "R" NGK plugs, which is not what I really need. I really need standard heat range plugs and regular NGK's. Correct?

 

If I am not mistaken the "R" has nothing to do with heat range it means resistor.

 

Ok. I was looking at the wrong year model in my clymer manual. The plugs that are in the bike are the correct heat range. anymore ideas?

 

bump.

 

I don't know anything about your idle but I do know you didn't spell fluctuating correctly. :lol:

 

Normally fluctuating (how's that) idle is caused by unwanted air, do the usual checks.

 

I put plugs in mine tonight and it made a huge difference when idling. I was constantly fighting a rough idle and wouldnt let it go below 1200 because I was worried it would die and wouldnt start back up.
oil change didnt hurt either

 

Thanks for the input everyone. I'll start with some new plugs sometime soon. If that does not work I will go into the more technical stuff. You all are always good for a laugh. (fluctuating)!

 

Here is something everyone may find interesting. I got to thinking about the idle and after searching threads related to octane ratings I decided to try running some 89 octane in my bike as opposed to the 87 I was running. So I rode my bike until it was nearly bone dry running on fumes. Filled it up with some 89 octane and the idle is holding much better. Unlike the xj I think this bike is designed to run on a little higher octane fuel. Just a thought but I will see how it works out.

 

Ok I have been riding a few days with 89 octane and the idle has gotten better and better. I think my theory was right. I must have had some gunk in the carbs, but since I have been running the 89 the bikes performance has improved noticeably.