Adjusting idle speed

[Palm9]

Hi, I'm new to this board. I've got my GS500F since January this year, havent ridden much yet, but season just started here in Denmark, so I'm looking to stack up on kilometres on my GS during the next few years whilst I'm studying. I came from a small Honda CBF125 which I used to learn the ropes on. I also ride a classic BMW R65 airhead just for the heck of it.



Anyway, my GS500F is a K5 model, first registered in 2006. Currently it idles at around 800 rpm, and it'll stay there when warm/hot. No other problems or anything, doesn't cut out either. I'm just slightly concerned about the low idle as it does sound kind of rough. The bike only has 16.000 km on it (~10.000ish miles). I would like it to idle closer to 1000 rpm, as it does currently sound like it does not like the low idle.

Is there a screw to adjust or something like that? And where? I'm familiar with basic maintanence such as oil changes, spark plugs, valve clearances, but as my old Honda was a fuel-injected bike, all things carburetor is new to me.

I'm looking forward to your answers
All the best, Frederik

[cWj]

Welcome.

From the wiki: http://wiki.gstwins.com/index.php?n=Maintenance.AdjustIdle

Get acquainted with that search box. It will be your friend. 

(although you sometimes have to retry a search from the "no results" page to get results...or maybe Searchy just likes to mess with me personally.)

[Palm9]

Wow that's amazing! Would not have guessed that it was that simple! Cheers!   

[cWj]

 

Read through whole wiki. The answers to your next 15 questions about the bike are probably there.

Have fun with all your air-cooled goodness.

[Atesz792]

Welcome! Nice bike you have there, bonus point for the picture, 'cause we love them!

Edit: if you don't sit a lot in traffic jams, you might want to raise the idle to around 1500 RPM. That's where some wise members (and I ) like it, of course opinions will vary. Easier cold starting, less of a chance to stall, etc
Also camshafts HATE low revs. Factory spec is ~1250RPM, don't go below that.

[Palm9]

Thanks guys. I'll have a thorough look through the manual

I was told by the guy I bought it from, that it'll be more economical if my idle is lower, but does the idle even change anything while riding? As far as I know of, the idle speed is only there to make the bike, well... idle when no throttle is applied, right?

- I increased the idle to 1100 rpm, but if 1250 is better, I guess that's an excuse to go for a ride to warm it up again tomorrow 

[Big Rich]

If the idle is too low, you're not circulating as much oil at idle (hence why people recommend it to be at spec or slightly higher). But if it is TOO high, it can cause problems with engine braking when you let off the throttle.

As far as being economical...... a heavy right hand will waste more gas than a low idle.

[ShowBizWolf]

Hi Frederik, welcome to the forum!! I totally agree with Atesz, thanks for the pic    Very clean looking bike 

I was curious to see what an R65 looked like so I googled it... that looks like a sweet bike too! Do you have any pictures of it you can share?

[cWj]

I was told by the guy I bought it from, that it'll be more economical if my idle is lower, but does the idle even change anything while riding? As far as I know of, the idle speed is only there to make the bike, well... idle when no throttle is applied, right?

- I increased the idle to 1100 rpm, but if 1250 is better, I guess that's an excuse to go for a ride to warm it up again tomorrow 

The idle adjust is basically just a throttle stop - it holds things open a certain amount even when the twisty go-fast thingy on the right handlebar is fully disengaged. That doesn't change unless you change it.

The idle speed, however absolutely changes. As the bike gets warmer the idle speed increases  As it cools down (which it will - there is a reason we call it a "cold-blooded" engine), the idle speed will drop. The point of adjusting to 1250 as the book states is to keep it above too low while giving it some room to warm up.

To be fair to the PO, I saw better gas mileage when I tried setting my idle between 1k and 1250. However, the bike would never really warm up fully, cooled back down quickly in traffic or when stopped for a short period (sluggish) and I had to be careful about it stalling when coming to a stop. Mind you - this was in summer.

After adjusting to a higher idle (I try to keep a tick under 1500 indicated). The bike isn't so stall prone, warms faster - and this was in the winter.

I have been messing around with my carb settings, but I was 60s mpg with the idle set low and mid-high 50s with it set higher. I stopped checking for a while. I've been heavy handed with the throttle the past few months (when you can ride it, you gotta RIDE it  ), so I need to do a few tank's worth of normal riding to see where the mileage is now.

The point of a long post being: the cool thing about our bikes is how much we control we have over how it runs to get it to be the bike we want it to be.

Correctly adjusted valves are also important to maintaining a good idle (and healthy valves), so make sure that's in spec, too.

[Palm9]

I noticed today that since I turned up the idle the other day, its much harder to start the bike from cold. We have around 0ºC (32ºF) here right now so I'm excited to see if warmer weather will help it. I almost have to give it full choke when starting, so I'm having second thoughts about upping the idle even further :/


(Argh, those security questions are bugging me, is there a place where the precise answers are defined? The one with the hose and the fuel to the inlet or whatever I cant get right!)

[Big Rich]

Don't worry - after your 5th post you won't have those questions to deal with.

And don't be afraid to use the choke wide open, that's what it is there for. If the engine is fully warmed up (after a 20 minute ride or so) and you turn the choke on all the way, your idle will be around 5k rpm. Definitely don't want it idling at 5k rpm very long, but also not the worst thing you can do to an engine.

[Palm9]

Ah okay, I was just concerned that it might become worse over time, and eventually I would 'run out' of choke. Before with my very low idle, I only had to use half choke

Cheers!

[Atesz792]

OMG, freezing and half choke?
I have to use full choke to start unless it's the middle of summer, above ~30°C.
Freakin' EU emission rules and lean running bikes...

[Palm9]

Haha that sounds crazy   
Perhaps wear and tear? I don't know, yours does have much higher milage on it than mine 

[Janx101]

It's not a choke like on a car carburetor. .. it's more just a little pilot jet and the screw you wind in/out to let the slides? Open just a bit. .... there is no choke butterfly/flap!

[Big Rich]

Janx is right - while everybody calls it a choke on the GS500, it is actually a "fuel enrichment circuit". So it doesn't choke the carbs of air, it adds gasoline to the mix via plungers.

And the idle adjustment knob pushes on a bracket attached to the butterfly valves inside the carbs.

Palm: here in the USA we have a government agency that said the GS makes too much pollution at idle. So the pilot jet (idle circuit) is smaller here than the rest of the world.

[yamahonkawazuki]

also the EPA ( Everybodies Pain inthe A**) speaking of the enrichment circuit, i kinda wish the carbs had a system similar to my sportster, many times choke wasnt necessary. a simple open close motion on throttle 2x, would prime it by squirting fuel in.   
Aaron