1 Another hard starting problem Mon Feb 26, 2018 4:09 pm
glennpm
Silver member
I've been an occasional lurker on this site for a few years but now need help with hard starting on my 87 K100RS. I've had the bike for about 15 years now and it presently has a Flexit sidecar attached. I am retired and split my time, mostly in Maine and here in North carolina where I'm trying to get my 87 K100RS running agin. It has been laid up for almost a year. I had a real hard time getting it going last week and also a year ago when I last rode. Last week I was able to get it going and went out for about a 40 mile ride during which it ran well. Since that ride I can't get it starting well at all. I suspected a fueling issue and started there.
After the recent hard starts, I started to dig in and see what was causing my trouble and have done the following during the last several days:
- battery is charged up but I'm beating it up pretty bad with the attempts to start. I have it on a charger that will act as a 50amp jumper which I've resorted too during my start trys.
- Drained tank and put in a some fresh no ethanol 90 octane that I can get here.
- Checked that fuel pump is working. Get lots of return line agitation for the pressure relief when I look in the tank with a light
- My fuel filter was changed a few K ago but I pulled it and verified that it wasn't clogged. I can blow through it easy
- Put a timing light on each ignition wire lead and all are functioning.
- Plugs were all the same and wet. I put in a new set of D7EA plugs, gapped to .024"
- I had never pulled my injectors, only running cleaner and suspected them. I got a refurbished set for mrinjector last weekend and put them in
Tried starting again and was only able to get it going after multiple attempts by holding the starter button in and NO fast idle aka "choke" on it. Pulled the headlight socket and parking lamp fuse to decrease load. Since it won't run if I "choke it", RPM is real low and alternator is trying to charge the battery (still on charger BTW).
- Checked for vacuum leaks around the plenum boots, air plugs,etc. with a small unlit propane canister. No increased idle speed so assume no leaks. Z tube replaced a year ago and good shape. Wish they were cheaper!
- Pulled the fuel tank again and checked for broken wire and plug insertion. I did have mouse nest on top of the motor under the air box but no where else so ...
- Pulled the air filter to make sure there was no mouse leavings. It was fine and I reverse blew out the filter. Its in great shape. Air supply to filter is unimpeded.
- Pulled the fuel injection plug and re-inserted
Did a bunch of searching on the net and especially here since I got so many hits. Next pulled out "Crazy Frog's" great diagnostic chart and started plowing through it.
- fuses all good and wiring and plugs intact
- Kill switch/starter button good and in good shape. I last re-furbed it about two years ago. I pulled it and checked the back and it is clean and has my dielectric grease on it.
- checked and temporarily pulled the plug off the idle switch with no change
- pulled the cover over my Hall effect sensors and verified wiring and visual condition good with no slippage of my timing. I put new Hall units in about 20K miles ago.
- Last Saturday during the last run in my garage of any length, the radiator and light kicked on. I also checked the resistance of the temperature switch through pin 10 of the FI unit and it is correct for temp during test.
- went through the "electronic ignition module test" where able. didn't check the "engine running" ones for obvious reasons. Pin out on the diagram is for the male spades on the unit and not the female plug sockets for info. I sent a note to Crazy Frog about this.
- I also tested the FI unit female pins and found no problems
- For the airflow meter pin checks I got:
Pin 7-5 66.7 ohm
Pin 7-8 324 ohm
Pin 8-5 365 ohm
Pin 8-9 202 ohm
- checked and verified resistance on primary and secondary circuits of my coils
- verified with my stethoscope that all the re-furbed injectors were clicking when last run Saturday
So I'm stuck now. The only way that I can get it to start and that is real rare now, is if I hold the start button in to richen the fuel mix. I can't get it to start with or without holding the starter on with the choke engaged. Gaps for the choke are correct and checked this after. Bike will maybe run two minutes and then stall out. Any attempt at throttle mostly fails.
Hoping that I missed something and looking for help here please. thinking my battery is not dong its job anymore too.
Glenn
Last edited by glennpm on Mon Feb 26, 2018 4:38 pm; edited 2 times in total (Reason for editing : Add info)