Motorcycle Repair: 1980 Suzuki GS450, throttle grip, rubbers

Question
Hello, I have a 1980 GS450 motorcycle that has just started having a problem with idleing at high rpm's. The bike idles at 1000-1200 rpms. After riding the bike for about 5 minutes when you come to a stop the bike wants to idle at 4000 to 5000 rpms. I can turn the bike off and restart the bike and it idles normal until I twist the throttle grip then the bike will not return to normal idle but but idles at 4000 rpm's I have gone through the carbs. I tried spraying starting fluid around the intake rubbers and notice no change in the rpm's. The throttle slides in the carbs seem to move freely and the diaphram rubber seems to be ok. Any suggestion?

Answer
Mike,Its possible that the cables or linkage may be giving you grief. Make sure there is a little slack in the twisting portion of the throttle also if the cables are starting to gum up or frey it will not let the bike idle down properly. Or if too tight the engine can rev if the bars are turned all the way to the left or right.