Temperature sensitivity?

[Guest]

Im wondering how sensitive these bikes are to temperature changes? I have my bike idling great at 1100 rpm when its 75-85 degrees outdoors, no issues at all. Today 61 degrees 83% humidity (unseasonably cool) and it didnt want to idle over 1000rpm. It even stalled when I coasted to a red light 25 minutes into the ride, which never happens. I didnt adjust the idle screw which I know would have helped but is this necessary?! I hate messing with it when normally it runs perfect. Is this common to need to adjust the idle screw for 20 degree temperature changes?

[tom203]

Not common for mine! I'd guess you got one cylinder not firing consistently ( maybe partially blocked idle circuit) and at times it drops out. But I'm surprised it actually stalls out as mine will keep going on just 3. I'd opt for a dose of Seafoam or equivalent. I'm assuming you have already done a proper carb cleaning.

[sedelen]

It's no big deal to adjust the idle screw a tad. If you have a cold blooded bike like my '82 GS1100E, it could take some time to get to really warmed up in cooler weather, a 20 degree temperature change does make a difference on that bike.

[gearheadE30]

My '79 GS750 is pretty much fine without any changes, regardless of temp. It will be up or down ~200 rpm at idle from a cold winter day to a hot summer day, so it only really ever takes small changes. I've never had it die on me because of temperature.

[Badooka]

My GS's loved it hot- cold blooded 100%

[ndbaker]

Not common for mine! I'd guess you got one cylinder not firing consistently ( maybe partially blocked idle circuit) and at times it drops out. But I'm surprised it actually stalls out as mine will keep going on just 3. I'd opt for a dose of Seafoam or equivalent. I'm assuming you have already done a proper carb cleaning.

I think your right about the blocked idle circuit. #2 header does not even get warm until i ride the bike. I can fell it kick in at about 1/2 trottle and the bike gets a sudden burst of acceleration. I ran 1/2 can of seafoam directly into carbs and the other half in the tank to try to clear it up....unfortunitly no luck. Anyone have good experience unblocking a circuit with seafoam? I reall want to avoid taking carbs off/apart again for the thousandth time.

[tom203]

Seafoam probably has done all it can in your case- once the idle circuits get seriously gunked, it's hard for cleaner to get at them (find a way up passages) without total immersion.
Proper carb cleaning is calling!

[Nessism]

Have you vacuum synced the carbs? Some idle variation is common, but it shouldn't vary overly so.

[Steve]

I reall want to avoid taking carbs off/apart again for the thousandth time.

Evidently your first 999 times weren't quite good enough, you will have to do it at least once more.

Have you vacuum synced the carbs? Some idle variation is common, but it shouldn't vary overly so.

A poor carb sync will also make it "come alive" at half-throttle. If one carb is closed more than the others, it simply won't be contributing at idle. As you open the throttle, it will come on-line and start helping.

If a carb sync does not help, you will have to clean the carbs (again).

.

[ndbaker]

2 words.....cracked boot....

Replaced # 2 intake boot and problem solved. This boot was a 2yr old oem. Luckily was never an issue with my excellent carb cleaning a few yrs ago!

[OMGCat!]

Mine will definitely idle a little higher at 90 degrees than 50 but only 100 rpm or so.
One thing I have noticed is that it will idle crappy if the gas in the tank is over a month old. I hadn't been riding much lately and the few times I did take it out I noticed the idle was low to where it was almost stalling.
I figured it sitting must have gunked the carbs and it was time to pull them off for a cleaning.
Then, I got gas and all was back to normal within a few miles. Ethanol gas is just crap. Now that I'm back to my 60 mile a day commute it's totally back to normal.