So I bought a K100 blind on eBay, (everyone stop laughing). I knew there was a starting issue when I bought it. ( no seriously, stop laughing)

I'm working my way through crazy frogs trouble shooting guide and I have to say it's a cracking guide.

Anyway, fuel pump runs on quick press of the starter, I've had the injector rail off and the injectors spray fuel and cut off when the starter is pressed and released.

I was checking the values for the air flow thing and was getting an open circuit so I've removed it and checked the values on its pins and the readings are OK
Pins 5-7 = 93 ohms
Pins 7-8 = 352 ohms
Pins 8-5 = 362 ohms
Pins 8-9 = 209 ohms

So I'm now going to check the continuity of the cable and then refit the unit and test again.
I'll let you know how I get on.

Welcome to the forum, Jonny.
The doctor(s) need more information about the symptoms.
There's nothing more the old gits on this forum enjoy than a good problem.
So I'll start. Does it start at all or never has started since in your tender mercies? 

Thanks ComberJohn,

It was running for the previous owner, but it gave out on him on the motorway, after some tinkering he gave up and I bought it, this was about a month ago, but no I've never actually seen it move under it own steam.

I've only just got round to having a play, I have tried to start it and it did fire and semi-ran while the starter motor was running but died when the throttle was revved, so I figured sensor of some kind, so I'm in the process of going round bike testing everything that I can find.

Oh, and there is fuel leaking from exhaust joint and I have had the plugs out and there is a spark there.

JonnyHonda wrote:Oh, and there is fuel leaking from exhaust joint and I have had the plugs out and there is a spark there.

Sounds like it getting to much fuel, unless you have been doing starting attempts all day.

First the plugs is wet fouled, and need to be dried.
Second I would have checked the temp sensor.

Measure the resistance between contact #10 and 13 at the injection ECU connector
(female side).
Count from the rear end, also the empty slots.
In the troubleshooting guide at the portal you find a table, resistance vs. temperature.

Thanks Inge K. I'll do that tonight and post my findings as soon as I can

So I've checked the continuity of the airflow unit and its fine, I was just counting the pins wrong. Cleaned plugs and tested the water sender. 

The water temp send gives a reading of about 3.1k which on the graph I think is around 16°c which would be about right.

On speaking to the PO he says his troubles started after he fitted an extra set of rear lights that look as if they were spliced directly into the rear light wiring, could this have fried something? Or do I need to start swapping out computers?

This is fun...

Incidentally I notice the fuel warning lights aren't on, what is the limits on these as I know the level is very low and I would expect at least one to be on?

Well been testing checking and tinkering with no joy-joys, so while bored at work I traweled eBay for an EFI unit, I thought I have to start somewhere. Found one ordered it, comes Wednesday.

Anyway, thought I'd have another tinker tonight while wifey is at work, tank off and I spy a stray brown wire. Yep a ground wire, looks like it enters the loom and heads north to the ignition unit.

New connector fitted tank on, starts first time.

Life Lesson? Check twice, check again,  Sods law says you've missed something simple.

So starts runs rough, wavey tacho needle and and won't idle, but they are problems for another day.

Thanks everyone.

I have seen a few Ks do that now and the key is one earth for starter sequence and a second earth for running. If the second one is faulty then it dies as soon as you take your finger off the button.

You did right to check that earth, also one that can do it is the connection under the seat, the one to the computer. If the connection is dodgy you can get same thing. Taking battery out or even disconnecting a terminal could disturb that and the PO may have done that when he was altering the rear lights.

JonnyHonda wrote:I'm working my way through crazy frogs trouble shooting guide and I have to say it's a cracking guide.

welcome to the forum Jonny Honda.

Winter is coming and you never know what I will do.
Maybe writing another document on a specific repair??? Time will tell

Glad that you were able to fire your engine up. That's a reward for your hard work.

CF