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Old Today, 10:19 AM   #1
trampred OP
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Joined: Nov 2014
Location: Lost Angeles
Oddometer: 35
Idle speed dropping when very hot

I've been having to ride my R75/5 in a lot of LA stop-and-go traffic recently, with temperatures reaching 90F, and have noticed that when stopped in-gear with the clutch pulled in, idle will be fine at what sounds like 900 or so and then, after a few seconds, drop to just barely ticking over. If I don't blip the throttle then it will sputter and die occasionally.

If I put it in neutral at a stop, this seems to keep the idle steady.

Rode around at night yesterday and didn't notice this problem as much... could it be temperature related?
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Old Today, 10:55 AM   #2
Solo Lobo
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Joined: Mar 2004
Location: Shoreline, WA
Oddometer: 8,900
start by re-adjusting your clutch per the BMW way and see if that eliminates any possible clutch drag and helps
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Old Today, 10:59 AM   #3
Beater
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Location: Atlanta, GA, USA
Oddometer: 3,353
Save your clutch and find neutral!
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Old Today, 11:00 AM   #4
CafeDude
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Location: Westchester County, NY
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^ if that doesn't do it, check your ignition advance mechanism. Make sure both springs are there and the counterweights move freely. Does it fire up from cold easily? If not, pull your idle jets and make sure they are clear of any old fuel goop.
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Old Today, 11:25 AM   #5
190e
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One bizarre possibility where I have experienced similar symptoms. Check your floats are not close to being sinkers resulting in an excessively rich mixture after a few seconds at idle.
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Old Today, 12:55 PM   #6
trampred OP
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Joined: Nov 2014
Location: Lost Angeles
Oddometer: 35
Sound advice and been meaning to change the clutch cable anyway so will do:

1. Clutch adjustment
2. Carb floats and jets check
3. Ignition advance mechanism

And we'll see what happens...
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Old Today, 05:46 PM   #7
trampred OP
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Oddometer: 35
Replaced and adjusted clutch as per BMW specs and that doesn't seem to have helped any, so on to the carbs...
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Old Today, 06:12 PM   #8
Beezer Josh
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Joined: Jan 2013
Location: 15.6 miles from the U.S. Capitol
Oddometer: 1,117
I would switch the order of 2 and 3 on your list. Timing should be checked and set before you tinker with the carbs.
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Old Today, 07:31 PM   #9
BarryT
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Location: Edwards AFB California (Rosamond CA)
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Check your rocker end play. If they are to tight they can cause the idle to drop when coming to a stop.
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