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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: subforry on April 03, 2015, 11:50:11 AM

Title: Hesitation or dieing after start
Post by: subforry on April 03, 2015, 11:50:11 AM: Hi all,

Over the past 2 months my K1100RS has started to be more and more fussy after a cold start. Now I have to use the throttle advance (choke) or it will die. There is hesitation that seems like a fuel mixture problem. This all goes away after about 5-10 minutes of riding. I changed the fuel filter 2.5 years and 5k miles ago. It was so bad on my last trip that I tried a bottle of Techron. The hesitation is like a dirty carb that or poorly tuned carb that does not atomize the fuel until it warms up. Once it is warmed up, it runs great.

Any thoughts?
Title: Re: Hesitation or dieing after start
Post by: Scott_ on April 03, 2015, 07:24:20 PM: My 1st thought would be to check the water temp sensor. Both the connections, and the resistance reading of it.
I think there is a post in the Lieberry with a chart/listing of approximate resistance/temperature.
Another check would be to look for any vacuum leaks, old, cracked hoses, o-rings, the little caps on the balance ports, etc... then can/will give you grief.
Title: Re: Hesitation or dieing after start
Post by: subforry on April 03, 2015, 10:00:48 PM: How about this being unplugged? Seems like an air temp sensor. Just changed the oil and found it unplugged. After I changed the oil and plugged the sensor back in it seemed to run better. The u clip on the plug is missing, guess I need a green zip tie.
Title: Re: Hesitation or dieing after start
Post by: Scott_ on April 04, 2015, 09:02:01 AM: Yes, that is the air temp sensor.
It would have an effect on the fuel enrichment, but I don't think that it would affect it as much as the water temp sensor though.
Title: Re: Hesitation or dieing after start
Post by: The Mighty Gryphon on April 04, 2015, 09:18:07 AM: Not to change the subject, but what is that insulation in the photo of the air temp sensor? Looks like a fuzzy johnny blanket
Title: Re: Hesitation or dieing after start
Post by: subforry on April 07, 2015, 12:06:41 PM: Short ride to work and no problems. Still when I get time I will check the water temp sensor.

The fuzzy Johnny blanket is the common heat and sound insulation you can get at auto parts stores. It is felt mat about 1/4" thick with a reflective heat resistant material on one side.
Title: Re: Hesitation or dieing after start
Post by: F14CRAZY on April 07, 2015, 12:12:24 PM: How cold are we talking? Below maybe 40 degrees I have to use full "choke to start," which I can pull off to half after maybe 30 seconds, then i leave that on for a few minutes after taking off
Title: Re: Hesitation or dieing after start
Post by: subforry on April 07, 2015, 01:10:13 PM: Quote from: F14CRAZY on April 07, 2015, 12:12:24 PM
How cold are we talking? Below maybe 40 degrees I have to use full "choke to start," which I can pull off to half after maybe 30 seconds, then i leave that on for a few minutes after taking off

What I said was not clear. I meant cold as in when I first start it in the morning or after it has cooled. Before I almost never use the choke because the air temp is usually 60F