1985 K100RS will not start - K-Bikes.com - Excellence in Motion
LinkBack Thread Tools Display Modes
post #1 of 4 (permalink) Old Feb 24th, 2014, 6:38 pm Thread Starter
Join Date: Feb 2014
Location: crestview, florida, USA
Posts: 6
1985 K100RS will not start

1985 K100RS will not start.
A. Engine turns over
B. New gas in tank
C. Removed spark plug one at a time. Ground plug on frame appears to be a good spark. All four plugs have spark.
D. When I removed plugs they were damp so I presume they are getting gas.

Please help it is driving me crazy. Please explain course of action I should take in detail because I am not a Master Mechanic.

Thanks you Guys

raybakerjr is offline  
Sponsored Links
post #2 of 4 (permalink) Old Feb 25th, 2014, 3:16 pm
Senior Member
Join Date: Sep 2006
Location: Austin, Texas, USA
Posts: 190
Just some stuff to get started with:

You might try a new set of plugs.
Make sure the battery is fully charged.
Unseat and reseat the main computer connector under the left side panel.
I have had the injector pintle pins stick after sitting a long time.
I have had the engine water temp sensor fail- gas was shooting out of the exhaust.

Nothing else comes to mind right now.
Has the bike been sitting for a long time?


'17 R1200RS, 2 yrs. 27,000 mi.
'16 R1200RS, 18 mo. 28,000 mi. (gone)
'03 R1100S Boxer Cup Replika 6/200
'85 K100/1100RS, 34 yrs. 326,000 mi.
'05 R1200ST, 8 yrs. 57,400 mi.-3rd deer killed it.
'11 R1200RT, 2 yrs. 30,000 mi. (gone)
'99 R1100S, 2 yrs. 15,000 mi. (gone)
'96 Ducati 900SS/SP, 12 yrs. (gone)
500,000+ BMW miles
duckbubbles is offline  
post #3 of 4 (permalink) Old Feb 25th, 2014, 7:34 pm
Join Date: Dec 2012
Location: York, PA, United States
Posts: 106
I would make sure you are getting gas. I have been fooled a few times by damp plugs on my K100. The plugs are damp but the fuel pump isnt firing.

Listen for the fuel pump firing. You should hear it when you hit the starter. If you dont hear it, check the round connector on the left front bottom of the tank. If you are not sure, you can do one of two things. Remove the pump, run some leads from a battery to the pump. It hasnt mattered about positive or negative on mine for testing; reversing the leads makes the pump spin in the other direction. The pump should fire. Another method is to pull one fuel injector out, put it in a large glass, hit the starter and look to see if gas sprays out the injector.

Also try starting the mc with the clutch pulled in. There must be neutral sensor somewhere. I havent dealt with that on my K100, but on some mcs failure results in the starter turning but the engine not firing.

Last edited by 97tiger885; Feb 25th, 2014 at 7:42 pm.
97tiger885 is offline  
Sponsored Links
post #4 of 4 (permalink) Old Feb 26th, 2014, 4:25 pm
Join Date: Dec 2012
Location: York, PA, United States
Posts: 106
I thought of an easier way to tell if the fuel pump is working. Remove the gas cap. This is easy. Open the cap. Take out the screws you see. The unit will lift out. Reach in and touch the fuel pump with one hand. Hit the starter with the other. You should feel the pump vibrating if it is running.

I pulled my pump a few times because I needed to find out if the pump had failed, the connectors on the harness were bad or if the electronic component that sends the signal had failed. In my case, the pump tested fine. The connectors had worn on the harness. I cut off the old connector and spliced on a used one.

Removing the pump is not complicated. Frustrating and dirty. I can talk you thru it if it comes to that.

Last edited by 97tiger885; Feb 26th, 2014 at 4:34 pm.
97tiger885 is offline  

Quick Reply

Register Now

In order to be able to post messages on the K-Bikes.com - Excellence in Motion forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Similar Threads
Thread Thread Starter Forum Replies Last Post
1991 K100RS won't start oilhead110 Other K-Bikes Discussion 3 Oct 1st, 2011 11:25 am
Loose hose 1985 K100RS MBurkhea Other K-Bikes Discussion 4 Jun 10th, 2009 11:55 pm
1985 K100RS, flat spot/miss at 2000-3000 rpm bowl_of_cereal Other K-Bikes Discussion 23 Apr 26th, 2009 9:27 pm
K100RS Won't Start Mudbug Other K-Bikes Discussion 8 Oct 13th, 2008 1:45 pm
Omega #s for 1985 K100RS jmalin Other K-Bikes Discussion 3 Sep 3rd, 2007 9:15 am

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome