Idle speed increses after riding 15Min and has suddenly gotten harder to start

[TheOzTurkish]

Hay guys I'm a long time reader (perv???) I did quite a bit of research on different bikes before choosing the GS and the wealth of knowlage and love of this bike on this page helped make the decision easier.

First my bike its an '03 completely stock with 14000kms when I purchased it it had been advertised in the dealership for a good 6 months I don't know how long it was actually sitting there though.

after riding it home and filling up the tank me and the old man changed the oil, adjusted the chain tension and I checked the spark plugs but didn't replace them as they still looked good.

The bike started fine on choke and warmed up quickly to idle around 1000 (adjusted to 1500), although every now and then it would drop to 1000 for 1/2 a sec then go back up (is that called hunting?) sometimes it would do it a couple times in quick succession sometimes once per ride sometimes never.

That has since stopped however now it wont start straight away first crank sometimes second and it needs a blip of throttle or 2 then after the ride to work (about 20min) when I pull up its idling at about 2k and wont come back down.

Its only started doing this the last week or so.

I looked through the manual and service history that came with the bike its last major service was at 5000 odd KMs (almost 10000kms ago) in '06

SO I've roped in the old man and with a copy of the service and repair manual this weekend we're
- replacing the spark plugs
- synching, cleaning and adjusting the carbs
- lubing all the cables (clutch, throttle, choke)
- replacing air filter

Does this sound like the valves need a look at as well?

Besides the idle creeping up and being iffy to start it runs fine, warms up fine, takes off fine and there is no clunking, banging or ticking from the engine.

Cheers in advance for any suggestions, I look forward to tapping some more knowlage from you guys and maybe one day helping someone as well

[Janx101]

Mine idles cold at 1100 ish .. Once it's warm after about the same time as yours will idle around 1600 ish ... Don't know if it's a problem really? ... Maybe? ... It's done the same variation since I bought it almost 3 years ago though..dependant on how I have set the idle to start with

[TheOzTurkish]

Mine idles cold at 1100 ish .. Once it's warm after about the same time as yours will idle around 1600 ish ... Don't know if it's a problem really? ... Maybe? ... It's done the same variation since I bought it almost 3 years ago though..dependant on how I have set the idle to start with

well we adjusted it to idle about 1500 warm I'm not sure if we didn't let it warm up enough before we adjusted it and we actually went to far or if the carbs are full of shaZam! from the bike sitting around for so long or if the choke is sticking again because it was sitting around for a while  spose we'll find out when we pull her guts out

[Janx101]

I had initial issues with adjusting the idle just  after initial warmup ... It settled and stopped dicking around when I finally adjusted it after a short ride... Then it would idle without stall when cold ... Mostly... 

[TheOzTurkish]

yer might take another look at it on the weekend its a decent ride down there so should be toasty and see whats what 

[The Buddha]

Yea check the valves too.
I think you were rich to start with but have a tight valve.
Cool.
Buddha.

[TheOzTurkish]

Yea check the valves too.
I think you were rich to start with but have a tight valve.
Cool.
Buddha.

sick cheers

[Leadberry]

+1 for tight valves.  Had all kinds of idle problems when I got mine.  Found out there was zero clearance on 3/4 valves.  Now she idles cold at 1k RPM and warm at 1.25k RPM. 

[TheOzTurkish]

ok so whats the symptoms of hanging and poor clearance on the valves?
Just to throw a spanner in the works today it started fine and ran fine to and from work and wasn't idling high

[frylockjim]

ok so whats the symptoms of hanging and poor clearance on the valves?
Just to throw a spanner in the works today it started fine and ran fine to and from work and wasn't idling high

you can have problems starting and staying idle with tight valves. In some cases (my bike) you could have valves so tight that its hanging open slightly, which will cause a drop in compression. Anyone who knows more symptoms feel free to add

[TheOzTurkish]

Ok so today we dicked around with the plugs (colour was fine they were just old and actually somewhat loose (I must've ballsed up checking them when I got the bike) 2 new plugs nice and snug eliminated a misfire that had recently developed this morning and starts first time now (not sure about a full cold start though)

Apparently getting hold of an air filter is imposable, called one dealer Wednesday to see if they had the goods went in today and they had "used them all servicing a couple gs500's this week" no luck there the other dealer hadn't stocked the gs500 air filter since 2009    so fail there I think ill just get a k&n sent over quicker and easier then the shops, the one in the bike was ok to clean for now but will need replacing.

The carb synch was a pain trying to get to the vacuum nipple on the left side do you have to take the choke off? we weren't getting anywhere so said f%$k it for now tiddled with the idle screw and dropped it to 1200 and stayed there all day...... seemed we went to far the first time and hadn't warmed the bike up enough, when it was getting warm the idle went up to 2k where we set it.......... job jobbed

also lubed up the cables they were looking a little dry.

all in all the bike now pulls through the rev range instead of feeling asthmatic around 5k like it has been recently put 75kms on today 30km through the hills was was an absolute joy the whole way having the engine spinning away like a mad man and being chased by a skyline, so good in fact I may go again tomorrow 

next will be carb clean, sync, and valves.

[The Buddha]

Stock Air filter - was hi ngasoline and dry and reuse.
Cool.
Buddha.