1150GS Idle speed too high

jbr9990

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I have a 2003 1150GS that when it first starts up, idles at about 1100 rpm.
When it warms up to normal temp the idle speed seems to increase to about 1500 rpm.

Not sure where to start or what adjustments to make to reduce the warm idle speed down to about 1000 rpm
 
From the BMW manual:

EDIT: pages in wrong order, sorry.
 

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What ever you do???

DO NOT touch the small screws in behind the throttle bodies they are factory set

You should only need to adjust the Big Brass Screws and the Cables

ONLY set the Tickover when at 5 bars on gauge

You can try screwing in the Big Brass screws a 1/8th turn each (Clockwise from behind) to slow the tickover when hot, until you get gauges

When hot, the idle speed is 1050 plus or minus 50 RPM

The big brass screws are the big screwdriver slot boyos at the outer rear of the Throttle bodies
 
For 'BMW Synchro' and 'Moditec', read 'vacuum gauges'. The air bypass screws are the big brass ones on the back of the throttle bodies.

The vacuum take-off points are underneath the throttle bodies, blanked off with black rubber caps.
 
If you haven’t any gauges just screw in the big brass screws a half a turn each side to bring down the idle, or maybe a full turn if it’s still too high, just so long as you keep the turns even each side adjust it until your happy. I like my twins to idle at 650/750 rpms.
 
Mine was idling too fast, tried adjusting the brass screws, took it to Steptoe, small stone jammed somewhere where it shouldn't have been.
 
Another reason for a sudden increase in idle speed is the loss or split of one or both of the rubber caps on the vacuum takeoff stubs.
 
Out of curiosity, is there a similar way to reduce idle on a pre twin cam 1200?
 
Smelly Old Boots said:
1400/1450 at running temp
Click to expand...

waaaaaaaaay too high especially in town

You may find that your Stepper motor idle controls are stuck with age They open and close to adjust the airflow dynamically rather than the old fashioned method of having the Big Brass Screws as you did on Barbara

I may have a set of throttle bodies complete with idle motors here that might do you a turn
 
No simple fix so! I lied. At running temp it is about 1300. At initial start it’s 1450/1500 but settles.

Thanks for the offer Doc but at nearly 100,000miles I’ll leave it be.
 
Smelly Old Boots said:
I lied. At running temp it is about 1300Too high At initial start it’s 1450/1500Should be 1200 to 1250 ish but settles.

Thanks for the offer Doc but at nearly 100,000miles I’ll leave it be.
Click to expand...

I knew you have the big miles on it

If you are driving around Dub in traffic at those revs it will be quicker to overheat !! Especially coming into summer

You would be as well to get the stepper motors at least checked out that they are doing what they should be doing :rob
 
DrFarkoff said:
I knew you have the big miles on it

If you are driving around Dub in traffic at those revs it will be quicker to overheat !! Especially coming into summer

You would be as well to get the stepper motors at least checked out that they are doing what they should be doing :rob
Click to expand...

UM I will go back to the thread, but Stepper motors? now i understand. :beerjug:
 
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