Adjusting idle?

[beardedmonkey]

1978 GS 750

I had my idle up around 1400 because the carbs were dirty, but they've since been fixed. I read in my manual that the idle should be lower than that -- around 1050 or 1100 I think. Since the weather's begun to get colder, I've noticed it takes much longer for the bike to reach full idle, and just around town it never gets up that high any more. So, a few dumb questions questions (I think I know the answer, but figured I'd run it by you all):

1. Is adjusting the idle as the temperature changes normal? When I say adjusting the idle, I'm not talking about going into the carbs, I'm talking about that single, big screw above the carbs that you can reach by sticking your hand under the tank/above the engine while seated on it.

2. Should I just let it get nice and warm, lower the idle speed, and let it be (with the choke on for longer if need be)?

3. What is your recommended idle speed?

Thanks!

[spyug]

The idle should be the same cold or hot but seldom is. In the colder fall and winter months you may need to have it on choke for a couple of minutes but after that it should be good to go and settle down to where you set it, and I'd shoot for that 1100.

It may not be happy at that so you likely will have to play around abit until you find the sweet spot. I wouldn't get too upset if that spot is the 1400 or 1500 you've been at. As long as it doesn't die off or rev passed 2000 its all good.

While 1100 is the gold standard in idle, with these old bikes there is a lot of variation on that theme so don't get hung up on it.

Enjoy the riding we have left.

cheers,
Spyug

[BassCliff]

Hi,

2. Should I just let it get nice and warm, lower the idle speed, and let it be (with the choke on for longer if need be)?

Yes. All carb adjustments (vacuum synchronization, pilot "idle mixture" screws [or air screws and fuel screws on VM carbs], main idle knob) should be done when the engine is up to full operating temperature. Yes, it will idle lower when the engine is cold. That's what the choke is for. Just use a little more choke for a couple of minutes until the bike is ready to roll. Then turn off the choke after it's warmed up a bit.

Thank you for your indulgence,

BassCliff

[1_v8_merc]

I have a 2001, and it does the "same" thing....season changes, and the idle moves around differently.

If the idle is lower but very consistant, then just use the idle knob, and bring it up a little. You might find yourself bringing it back down again once summer hits, lol.

[Crankthat]

Sorry if this is considered hijacking a thread Beardedmonkey just wanted to learn a little more.
Is there a cable adjustment attached to throttle on a 78? Might be under piece of cone shaped rubber underside of throttle (throttle end of cable)
Would that be the better place to adjust your idle?

[Guest]

If your idle is having a hard time stabalizing as the weather gets colder I wonder when the last time you did your valves was?

[beardedmonkey]

Well, adjusted it down and it's all good. Does take longer on the choke, but that's to be expected. My neighbors officially hate me for letting the thing warm up at 5:00 in the morning, so I've taken to wheeling it down to alternating parts of the street so as to only wake up my closet ones a few days a week...

No problems with holding the idle -- valves and carbs done recently.

[BassCliff]

Hi,

Unless you are in really close quarters, warming up at 2000-2500 rpm shouldn't be too annoying, if you have the stock exhaust. But at 5:00 am I suppose any noise in the neighborhood will be annoying to neighbors.


Thank you for your indulgence,

BassCliff