Hello,
I just bought my first bike, a 2004 gs500f with 10000 miles on it for 1800 bucks. So far i really like but it seems to have some issues that I want to get sorted out before i start riding it alot. The bike doesnt like to start after its been sitting a day or two. In order to start it i have to crank it over and over on full choke and sometimes i have to use some starting fluid on it. When it does start it will usually run alright for a little while but then the bike starts reving up for no apparent reason. It will quickly climb to 6000 rpms and continue to rise slowly from there. The first couple times i rode it the revs would drop down when it was put into gear but now they just continue to rise on their own.

By reading some of the faqs im thinking it sounds like there might be a problem with a sticking throttle cable and maybe a carb issue. What do you guys think? I do all the work on my own cars but im not sure if i should just take this to a mechanic since Im pretty new to motorcycles and might miss something that a more experienced rider would catch.

thanks
Dan

after the bike sits for a while the gas evaporates from the carbs, so when you firs start to crank it there is no gas to fire. before you try and start it, turn the petcock to prime for 30seconds or so to fill the carbs, then turn the choke on half-to-full then crank it should fire in just a second. then with the choke on that far it will idle very high (over 4000rpm), slowly reduce the choke to keep it idling at 2000rpm or so then let it warm up untill it will idle with no choke at 1200-1500rpm. if it wont idle at 1200rpm with no choke after 15 min of riding then adjust the idle screw.

P.S. you also might have a vacuum leak or bad petcock.

P.P.S. Welcome to the forum!

I had something similar.

I just got the bike on the road and it started up just fine but when it was fully warmed up (15 mins riding in 80 degree nyc weather) it would idle at 4k rpm.

I looked around for a vacuum leak and other issues until i realized i was adjusting the idle screw when the bike was only half way to operating temperature.

The high idle sounds like an air leak. I don't have too much experience with them, but there's a trick of spraying starter fluid or something like that around the intake boots to see if anything changes. If it does it's an air leak. That was a horrible description of the process though, so let someone explain it to you that actually knows what it is.

The bike probably sat all winter before you bought it, so there's a good chance a good carb cleaning and lubing the throttle/choke cable will solve all your problems.

hope you enjoy it!

To clean the carb do I just pull it off and douse it with carbon cleaner or do I have to actually take the carb apart and clean out all the little bits?

Quote from: DangusKhan on March 05, 2010, 08:15:49 PM
To clean the carb do I just pull it off and douse it with carbon cleaner or do I have to actually take the carb apart and clean out all the little bits?

no, on brake/carb cleaner. it will kill your seals.

your carbs don't need cleaning. sounds more like a vacuum leak. get a tank of propane and move it around near the intake boots. if the idle changes, you've found the leak. don't blow yourself up.

unless the previous owner monkeyed with the carbs, you likely won't need to touch them. at least not until your rejet/pipe/whatever.

OK, it turned out to just be an idle adjustment issue. It is for the most part alot better now. I dont know if i still need to dial it in a bit but for some reason every now and then when i slow down to a stop the bike revs down and dies as i clutch. The bike idles great at 1600 rpms or so, should it still be a little higher to keep it from bogging?

Quote from: DangusKhan on March 07, 2010, 04:41:14 PM
OK, it turned out to just be an idle adjustment issue. It is for the most part alot better now. I dont know if i still need to dial it in a bit but for some reason every now and then when i slow down to a stop the bike revs down and dies as i clutch. The bike idles great at 1600 rpms or so, should it still be a little higher to keep it from bogging?

idle should be around 1200 when fully warm, which wont happen until its over 60* outside. I rode my bike for 2+ hours today in the 45-50* weather and it never got warm enough to fully shut off the choke.

so if its idling at 1500 or 1600 with the choke off and randomly dies should i turn the idle down and ride with the choke on?

I have the same problem and just sent it to the shop. Whenever I braked hard coming to a stop, the bike would die. I had the idle set around 1500. I've got a little hesitation in the lower rpms and a hanging idle issue too, so I just said screw it and let the professionals look at it. I'll try and remember to let you know what the fix is when I get the bike back next week.

sounds a lot like a vacuum leak or partly clogged primary jet.