Rough idle

[cajunito]

I recently aquired a `99 Tourer with 13,500 mi on it. I know the old guy I bought it from let it sit up a bit,& even though I've run it a couple of hundred miles or so it still idles rough... The mech who changed my tires told me to use Star Tron additive after I drained the carb bowls,which I did.. still idling rough... Any ideas? TIA!

[gordonv]

Usual answer is the slow jets, or all the jets, are a little clogged.

You want half a tank of gas and a full bottle of your favorite flavor of carb cleaners (Techron, Seafoam, Berryman's B-12, etc..). Drive the bike at low RPM (5th gear) and slow speeds (flates) for those slow jets are being used, for a little run (1/2 hr). Park. Repeat.

If it improves, others have found repeating with a different 1/2 tank of gas and cleaner did more for them that using only one type. You should notice a big improvment. After trying them all, and still no joy, then you might be looking at the bigger job of tearing them carbs down.

[Patrick]

Yep to what Gordon said.. However, my first question is how it runs from idle to 2500 and then from 2500 up.. If it tends to be 'doggy' and runs rough at the lower engine speeds and then picks up and runs well at higher engine speeds, then plugged low jets are the problem..
If it runs good at all speeds except for the idle, then maybe somewhere along the line the carburetor sync got screwed up.. That really shouldn't happen cuz this set-up is pretty bullet-proof, but, you never know what someone has done..
Regardless, running a few tanks laced with heavy doses of Sea-Foam thru it won't hurt.. If it still has a problem, let us know..

[Mr.BubblesVRCCDS0008]

Also check vaccum lines if it hasn't been de-smogged. If it has orginal lines on it they're most likely split where they hook to the intake runners.

[R J]

Easiest and quickest way to check the old girl out is grab a can of WD40. fire her up and let idle.

Spray WD40 in and around the carb bank.   If it smooths out temporarily, start replacing little rubber vacuum hoses with new hose.    I used silicone hose till I did a De smog.

Nothing happens above, then spray around the intake runners.

smooths out, you have some vacuum leaks on the 'O' rings in there.

 Now I'm assuming you have given the old girl a healthy, full can of SeaFoam, and run at least 40 miles below 40 MPH in 5th gear, and then let set overnight and repeat the 40 miles the next day.

Ya let it set with the cleaner in the carbs over night to loosen up any varnish that might happen to be in there.

The 2nd day, after 40 miles below 40 MPH, give her a few twist of the wick and see if it doesn't straighten out.

NO such luck, then get some help from a fellow rider and pull the carb bank to do some serious cleaning and then a carb syn-ch when all put back together.

Wishing you good luck.

After you once get the old girl straightened out, if she is going to set a week or longer, get a healthy taste of SeaFoam or equivalent into the carbs before ya park it.   Shut the gas petcock off and let the old girl sleep with her nice taste of booze.

Been doing it that way since Oct 1996 and 242 K miles.     Carb bank has not been out of the bike, so it must work in my case.

[scarylarry]

whats it do after idling...get on the hiway for 10 or 15 miles  npull into a conv. store ..start back up...how does she idle now...how whole bike feel after a good couple warm up laps?

[scarylarry]

ever need to choke to start?

[Patrick]

Yep, the boys are certainly right about the vacuum lines and caps.. Its the first thing to check..