Author Topic: Slow Idle until warmed up  (Read 3119 times)

Offline Jimbenge

  • Motobrick Curious
  • Posts: 18
Slow Idle until warmed up
« on: November 11, 2017, 10:36:04 PM »
I have a 1985 K100RT EML sidecar rig that I have owned for over 20 years and it has a little over 200K miles on it but only about 60K on the current engine.  I have not been riding much in the last 3 or 4 years and now when I start it, it barely starts and when it does it idles very slowly and if you give it a little gas it tries to stall, if I baby it along for a few minutes it will eventually start running fairly good with full throttle response.  It usually ruins fine after that until it cools down and sits for awhile.  I have it apart right now and was planning on sending the injectors off for cleaning thinking that maybe that is the culprit because it has not been used much lately, but it acts like low fuel pressure until warmed up ? bad fuel pressure regulator ?  its been doing this for a quite a while but seems to be getting worse.  Any ideas would be appreciated  Thanks in advance
2015 K1600GTL & Getaway Trailer
1985 K100RT-EML Sidecar w/Kwik Kamp Tent Trailer
2006 Harley Sportster Roadster 1200R (In-Town)

Offline The Mighty Gryphon

  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 6617
Re: Slow Idle until warmed up
« Reply #1 on: November 11, 2017, 10:51:53 PM »
First thing that came to mind was the injectors.  If anything is restricting their flow it makes sense that the mixture would be too lean when the throttle is opened when the engine is cold. 

As the engine warms up it requires less fuel, and at the same time the pintles in the injectors could be loosening up so that as the engine requires less fuel the injectors begin to deliver more and everything begins to work properly.  I think that we all agree that the idle engine is subject to fuel varnish gumming things up. 

It might be time to dump a bottle of Techron Fuel Injector Cleaner in the tank and doing an Italian tune up.  It can't hurt.
  • In my garage in Marilla, NY
  • '91K100RS White/Blue
Current:
'91 K100RS16V "Moby Brick Too"

Past:
'94 K75RT "Ilsa, She Wolf of the SS"
'92 K100RS16V "Moby Brick" (RIP, deceased in a vehicular assault)
'94 K75S Special Edition Dakar Yellow "Cheetos"
'89 K100RS Special Edition "Special Ed"

Offline beemuker

  • ^ Quintessential Motobricker
  • Posts: 1110
Re: Slow Idle until warmed up
« Reply #2 on: November 12, 2017, 08:12:09 AM »
First thing that came to mind was the injectors.  If anything is restricting their flow it makes sense that the mixture would be too lean when the throttle is opened when the engine is cold. 

As the engine warms up it requires less fuel, and at the same time the pintles in the injectors could be loosening up so that as the engine requires less fuel the injectors begin to deliver more and everything begins to work properly.  I think that we all agree that the idle engine is subject to fuel varnish gumming things up. 

It might be time to dump a bottle of Techron Fuel Injector Cleaner in the tank and doing an Italian tune up.  It can't hurt.
I had to look that up as I've not heard of one.
"An Italian tuneup usually refers to a process whereby a motor vehicle engine is run at full load for extended periods in order to burn carbon buildup from the combustion chambers, spark plugs, and exhaust system. It is performed after a traditional tuneup and often accompanied by an addition of fuel system cleaner to the fuel tank."
 :clap:
  • Panama City, FL
  • '00 R1100RT,’92 K75 RT,past tense:'83 R80ST, '93 K1100LT,,94 R1100RS K75s, Honda NC700, Suzuki Bandit 1200, bmw R75/5 Honda 750

Offline Laitch

  • Faster than a speeding pullet
  • Administrator
  • ^ Quintessential Motobricker
  • Posts: 10120
Re: Slow Idle until warmed up
« Reply #3 on: November 12, 2017, 10:01:21 AM »
  • Along the Ridley in Vermont.
  • 1995 K75 89,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline K1300S

  • ^ Quintessential Motobricker
  • Posts: 1257
Re: Slow Idle until warmed up
« Reply #4 on: November 12, 2017, 06:14:30 PM »
fix
 it
 again
 tony...



Project Thread "K75s Midlife Refresh"
http://www.motobrick.com/index.php/topic,7810.0.html

Tags: