GS425 Won't Idle Under 2000 RPM

[Anonymous]

HELP! A while back I cleaned the air filter and noticed alot of crud inside the airbox. I did the best I could with a few rags and cleaned the inside of the airbox without removing it. A few weeks later I started having problems with the idle. At lights I had to keep the throttle twisted to keep the bike running and when engaging the clutch the bike would stumble. High RPM operation seems okay. Yesterday morning I took out the bike for a ride and it went up to 100mph with no problem, except for the stalling at idle and the stumble.
I suspected that maybe dirt in the carbs was the problem. I removed the airbox and cleaned it thoroughly. I sprayed GumOut into all the holes in the carbs facing the airbox and plenty of crud came out. I re-installed the airbox and started the bike...same problem. Also, when I attempted to adjust the air screws after shooting some GumOut into the holes where they go, the left side carb has an effect on RPM while the right side I can turn all the way in with NO effect. If I try to turn the right carb screw out, the engine stalls even at 2000 RPM. Do I have more of a carb problem than simple spray will fix...disassembly warranted? What should I look for when I have the carbs apart? Are rebuild kits for this engine available? 1979 GS425

[AOD]

they had a GS425 in 79? interesting. i'm assuming you have a carb simliar to my 79 550...just two less. i was able to find a carb kit through cycle recycle 2 online...i bet they have one for yours. http://www.crc2onlinecatalog.com/Index_Main_Frame.htm

it sounds like the engine might idling off the #1 cylinder...that's why there's no effect when you adjust the other one. try turning both air screws to the same position...then set the idle with the throttle stop screw. then fine tune the air screws to see if that has an effect.

[Anonymous]

Sounds like you could use a carb sync. Maybe you can also use it to narrow down each cylinder's problems. See recent topic at http://www.thegsresources.com/_forum...ic.php?t=14962

Michael

[Anonymous]

Further Details Needed

THANKS FOR THE INFO GUYS! I NEED A LITTLE MORE INFO BEFORE I "SCREW" UP. THE SCREWS ON MY CARBS ARE AS FOLLOWS:

1) Each carb has a pilot air screw located on the outboard side of the carbs

2) The one idle set screw with the big plastic "star" on the end located towards the right side carb

3) The Throttle Balance Screw located in between the carbs down low

Which of these screws am I supposed to be adjusting and when? Talk about confusion!!

[Billy Ricks]

After you've warmed the bike up good then start the process running the bike on one cylinder at a time. I'm not familiar with your carbs but, the one with the star head on it should be for overall idle on both carbs. Then one of the carbs should be able to be adjusted for idle by itself. The mixture screws on the port side of the carbs help smooth out the idle.

Michael should be able to tell you which carb has the adjuster just for that carb. Do the carb that you have to use the star-headed adjuster for first. When you are adjusting get the idle up high enough to where the bike will run on its own. Adjust the mixture screws for the best idle. Then adjust the idle back to some rpm to compare the other cylinder to later.