[Solved] fails to start after some TLC

[Cafe racer]

K100RS 2 valve none ABS

***Warning**** routine maintenance can ruin your bike.. Was running fine, but now not. 1f600
Joking apart. The bike was running great.....

I was doing some cleaning and general maintenance, I cleaned around the throttle bodies and forgot to attach the temperature sensor that is lurking round the back of TB #1
I started the bike and it was revving its little nuts off.  Was running fine, but now not. 1f632

I quickly spotted my error and connected the cable to the sensor, but then I decided to check the throttle cable at the handlebar, the grease had congealed and was restricting the throttle return, I stripped and cleaned and applied a little new grease. 

It was now that I tried to start the bike...No joy.. Was running fine, but now not. 1f628

I have damp plugs with fuel.
I have a spark at the plugs (although does appear weak and possibly intermittent, I checked by holding the plug against the head with insulated pliers in the dark)   
I pulled out the injectors still attached to the fuel rail, and turned over the engine, all are squirting fuel.
I have checked the primary ohm's on the coils looks like they should be around 2.6Ω mine are both 6.0Ω


But it will not fire at all....

Problem turned out to be just the plugs, I was advised to swap them for another set, via another forum. I did and it fired up first press.

BTW my multimeter is a FLUKE 79 series II old but hardly used...

[Laitch]

I have checked the primary ohm's on the coils looks like they should be around 2.6Ω mine are both 6.0Ω

That is ≈60% more resistance than the primary should have. That much resistance could weaken the spark. Explain exactly how you measured them. What year is the moto? How many kilometers on the odometer.

[The Mighty Gryphon]

If your meter is anything like the cheap ones I use, trying to get a reading of resistance below 20-30 ohms will pretty much be a crap shoot that depends on the accuracy and zero of the meter, and the quality of the connection of the probes to the terminals.  Unless you have a meter that is well into the $100+ range you can't depend on the readings

In my world, 6 ohms means that the coil is okay.  Usually with coils you either see a low resistance near the spec or infinite resistance indicating a broken wire in the coil.

[frankenduck]

Moral of the story: If it ain't broke, don't fix it.

[Cafe racer]

All sorted thanks everyone...

[The Mighty Gryphon]

What did you find?

[Past-my-Prime]

Which wire was disconnected? or was it a vacuum leak?

I ask because this summer I had a similar problem: I replaced the Z hose but wasn't completely sealed behind the throttle bodies where I couldn't exactly see it. I had done a bunch of stuff and did not know that was the root of my problems but securing it properly did the trick.