Slow return to idle

[lrburke]

Hi there, I just finished up rebuilding the carbs on a 1982 GS650. The bike fired up immediately upon choking. After about 10 seconds I turned the choke off and the idle dropped to about 1400 so I adjusted it down to 1100. I thought I was in good shape until I revved it up to about 4000 and it kind of hung there and slowly came back to idle. I am certain I don't have an air leak. I don't really know what the initial setting is on the mixture screw. I have them about 2.5 turns out. Any suggestions from all you gs experts would be greatly appreciated.

 

[dr_fosg8]

more info

more info

What is the history of the bike? Have you had it long? What things have you done to be sure it is not an air leak on the intake? Not trying to pick you apart, but more information on the bike and maintenance is needed for someone to help.

 

[Steve]

You most likely did a fine job on the carbs, but did you also change the o-rings on the intake boots? These are the tubes between the carbs and the cylinder head. There are o-rings at the head surface, and they dry out and need to be replaced every 15-20 years, so they are probably past due. You can order rings from the same place you should have ordered o-rings for your carbs, www.cycleorings.com.

.

 

[lrburke]

slow return to idle

slow return to idle

Hi there again! I am working on this bike for somebody. I usually work on honda's but was brought this suzuki. The bike has 16000 miles on it. It has good compression and great spark. I was told the bike sat for a long time and it needed carb work. He was right! I completely disassembled the carbs and seperated them. I soaked each one of the bodies and used a water pick to make sure all the passages were clear. Re-assembled with all new o-rings on the fuel tubes and new float valves and new bowl gaskets. I use propane around the rubber intake boots to check for air leaks. The boots are free of cracks and o-rings are new. Let me know if there is anything else you might need to know in order to help me. Thanks

 

[dr_fosg8]

Sounds like you know your stuff! Is the stock air box being use and a good air filter installed and properly oiled ( if needed ).

I don't know if this would affect idle speed or not, but the valve clearances might need looked at.

 

[Guest]

it sounds like you've done a good job
other than making sure the airbox and the airfilter are on it may pay to go for a ride and see how things go after that
my bike seemed a little funny after i just started it after the carb rebulid but after a short ride it all settled nicely
i attributed this to the residue from the carb cleaner than needed to be "washed" away, but dunno really

 

[trippivot]

too lean is what causes the hi rev hang up and slow return to idle.

unless it is a mechanical restriction holding the slides/butterflies/cables/throttle twist tube to one degree or another.


too rich it will rev and then go under idle speed or possibly die then recover and return to idle unless it died.

 

[Fishman]

If the carbs are out of synch it might cause that problem. I have only synched three bikes ever, but two of them had the symptoms you describe and synching them up did the trick.

 

[waltfen]

I don't think this will cure your problem but I set the mixture screws on my 650 Kat to 1⅝ out.

 

[robertbarr]

If the carbs are out of synch it might cause that problem.

I second that. Since you've separated the carbs from the rack, it's 100% certain that they'll be out of sync, and that will cause the symptom you describe.