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Won't Idle with Cold Start

M

mhallman

Member
I apologize for this question because I'm sure it's been answered many times. I tried the search but couldn't find it... I've got a 2000 R1100RS.

Starting my bike in the morning, it has trouble idling without turning off. Sometimes I have to hit the starter a second time for it to fire up. I can push the high idle switch and it works relatively well, but it will still turn off sometimes without me tapping the throttle. Starting it warm - the bike is perfect (knock on wood).

After reading this forum for several years, something tells me the culprit may likely be the fuel injectors, but I simply don't know. And speaking of fuel injectors, is taking them off and taking them to a shop a reasonble thing to do to clean them. I've seen some contraptions that clean them, but I don't think I want to go there... To my knowledge, they've never been cleaned. I've owned the bike since 2016.

Thanks in advance.
 
mhallman - it is very straightforward to remove the injectors for cleaning. There are loads of DIY videos to clean them yourself. A pro cleaning shop will give you a before and after report of flow rate and how closely balanced they are. I had to ship mine to a professional - I think it cost me about $50 with the shipping. However, if when warmed up, your bike runs smoothly with no surging, then it doesn't sound like a problem with the injectors.

Personally, I never use the fast idle lever. I get dressed to ride - completely. Get on the bike, put a slight tension on the throttle and start the bike. Ride away. By the time I ride a mile, the bike will idle - a little low - without adding throttle. By the time I hit the next stop sign or light, it is running normally.

Check your throttle cables, at the throttle bodies and at the grip for free play. You may have too much free play. You must have some free play, but too much will negate the fast idle mechanism.
 
Something else to check, and pretty easy, is the crud buildup on the big brass idle air screws (both throttle bodies, of course).

First, use a pencil to put a mark on the throttle body just "outside" of the screw, lined up with either end of the screwdriver slot of the BBS (big brass screw).

Gently turn the screw all the way in until it just seats, counting exactly how many turns "out" it was.
Unscrew it all the way and remove... You'll likely find a deposit of black crud on the end, so wipe it off, maybe clean it further with a paper towel and gas.

There will also probably be more crud down in that little passageway, so use a Q-Tip with a little gas or alcohol on it to clear that out.

PUT ON SAFETY GLASSES and squirt some carb cleaner (or similar) down that hole to flush left-over crud out of and/or thru the hole... Don't get too exuberant with this, as the stuff will get into the intake port and then into the engine if the valve is open; I like to pull the bottom/peripheral sparkplug to give the stuff a place to drain (it doesn't burn well and may make the next startup a bit difficult).

Examine the condition of the O-ring on the screw; if it's cracked or flattened, a new one is called for... Last time I checked, they were not available separately, and I had to buy the "whole screw" (~ $6). (Anybody know a replacement O-ring part number?)

Reinstall the screw all the way in (gently) and then back out to the previous number of turns & pencil mark (the "old" location). Repeat process on the other side.

Another common cause of poor idle is valves that are too tight; I always set mine a little on the loose side of the spec. A proper cable + throttle-body sync job is also often beneficial.
 
Don't discount the value of the very basics. Spark plugs are cheap. An air filter is a little more money and a fuel filter a little more money and a PITA to change but if those are in rough shape, just about anything you do will be send you down the garden path.
 
Pauls1150 said:
Something else to check, and pretty easy, is the crud buildup on the big brass idle air screws (both throttle bodies, of course).

First, use a pencil to put a mark on the throttle body just "outside" of the screw, lined up with either end of the screwdriver slot of the BBS (big brass screw).

Gently turn the screw all the way in until it just seats, counting exactly how many turns "out" it was.
Unscrew it all the way and remove... You'll likely find a deposit of black crud on the end, so wipe it off, maybe clean it further with a paper towel and gas.

There will also probably be more crud down in that little passageway, so use a Q-Tip with a little gas or alcohol on it to clear that out.

PUT ON SAFETY GLASSES and squirt some carb cleaner (or similar) down that hole to flush left-over crud out of and/or thru the hole... Don't get too exuberant with this, as the stuff will get into the intake port and then into the engine if the valve is open; I like to pull the bottom/peripheral sparkplug to give the stuff a place to drain (it doesn't burn well and may make the next startup a bit difficult).

Examine the condition of the O-ring on the screw; if it's cracked or flattened, a new one is called for... Last time I checked, they were not available separately, and I had to buy the "whole screw" (~ $6). (Anybody know a replacement O-ring part number?)

Reinstall the screw all the way in (gently) and then back out to the previous number of turns & pencil mark (the "old" location). Repeat process on the other side.

Another common cause of poor idle is valves that are too tight; I always set mine a little on the loose side of the spec. A proper cable + throttle-body sync job is also often beneficial.
Click to expand...

Thanks for that. Great instructions. I cleaned the brass screws (they were definitely black) and the inside with some carb cleaner. Our temperature was a bit warmer today. When I started the bike, it did seem to do better. I'll check the valves next. Thanks again.
 
dieselyoda said:
Don't discount the value of the very basics. Spark plugs are cheap. An air filter is a little more money and a fuel filter a little more money and a PITA to change but if those are in rough shape, just about anything you do will be send you down the garden path.
Click to expand...


Good points. Will check those tomorrow. Just changed the fuel filter but will check the others. Following the KISS principle is always a great way to start...
 
mhallman said:
I apologize for this question because I'm sure it's been answered many times. I tried the search but couldn't find it... I've got a 2000 R1100RS.

Starting my bike in the morning, it has trouble idling without turning off. Sometimes I have to hit the starter a second time for it to fire up. I can push the high idle switch and it works relatively well, but it will still turn off sometimes without me tapping the throttle. Starting it warm - the bike is perfect (knock on wood).

After reading this forum for several years, something tells me the culprit may likely be the fuel injectors, but I simply don't know. And speaking of fuel injectors, is taking them off and taking them to a shop a reasonble thing to do to clean them. I've seen some contraptions that clean them, but I don't think I want to go there... To my knowledge, they've never been cleaned. I've owned the bike since 2016.

Thanks in advance.
Click to expand...

Since your bike runs well once it's hot, the most likely culprit is that the fast idle lever cable has stretched or is misadjusted--this happens on most all Oilheads. With the fast idle lever off, the throttle body butterflys sit on the throttle stops, which works well once the engine is hot.

During a cold start, the engine needs just a bit more air to idle well--about 2-3 degrees throttle open. The fast idle lever has two positions: midway up, where there is a detent; and full up, where you have to hold it to stay in position.

An easy way to tell if a misadjusted or stretched fast idle cable is the culprit is to open the throttle just a tiny bit and hold it there while you start. If it idles and starts better, go to the next step.

First look and see if there is any slack in fast idle lever cable at the adjuster with fast idle lever down, there should be no slack (but it shouldn’t be so tight that it has lifted the throttles off the stops). Next see that the fast idle lever pulls both throttle butterflys off the throttle stops when you lift it to the mid detent.
 
Last edited:
By the way, late last night I realized that you are talking about your 1100... My reference to the "bottom/peripheral sparkplug" refers to dual-plugged bikes like my 1150. Sorry if that caused some kornfusion!
 
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