Hard starting/temp sensor Q

[Tapio]

Bike starts without problems when hot. And also when cold. But not if its been parked for ½-1 h after a ride. Sometimes I have to crank it almost til the battery runs dead before it starts.
First thing to check, I think, is the temp sensors. There’s two: intake air, and oil temp. But how do you check them? I have read my Haynes repair manual from front to back, but there’s no info on them. I guess it’s because nowadays you don’t check them manually, but you hook the bike up to an OBD-system with a laptop.
But surely you could check them the old fashioned way, with an ohmmeter?
Does anybody have a procedure to do this?

Also, any thoughts on what else it could be, causing this, are appreciated!

[nab 301]

Also, any thoughts on what else it could be, causing this, are appreciated!

Sound like some sort of heat soak but for no logical reason I doubt if it's the temp sensors. I'd imagine the engine may run a bit rough / rich/ lean if a temp sensor was malfunctioning but that it would start. My bike would be almost cold after a half hour of non use.
Does it attempt to fire at all ? As has been said here many times , you need petrol , compression and ignition to start an engine
. It's just a small matter of finding which is failing.

Ignition leads? coil? is it twinspark? Fuel pressure. ? Sidestand switch? Hall sensor.....
There's nothing in the OE manual either , other than checking the Ign coil resistance.

[Tapio]

When it runs, there are absolutely no misfires or anything. It runs fine. Soot at end cans is greyish. When the problem appears, it’s like:
Crank… Crank… Crank… Crank… Crank… Crank…cough…cough… Crank… Crank… Crank…fire up!

It’s a twin spark. Yes, fuel pressure is something worth checking. And maybe the Throttle Position Sensor. I’m not absolutely sure that it’s the temp sensors either, but since the problem is clearly temp dependant, I think they are the first things to troubleshoot.

[Merecat]

I have a hazy recollection of a similar fault to this detailed somewhere on here. On that occasion I think it was a coil failing on an early twin spark model

[The Teutonic Tangerine]

May not be pertinent but I had a similar problem on a car (diesel) Started cold really well starting hot wasa nightmare - The cause a faulty injector.

[Tapio]

I have a hazy recollection of a similar fault to this detailed somewhere on here. On that occasion I think it was a coil failing on an early twin spark model

Now that you mention it, I recall that the previous owner said that the coils had been changed, on warranty. Will check them.

[Tapio]

May not be pertinent but I had a similar problem on a car (diesel) Started cold really well starting hot wasa nightmare - The cause a faulty injector.

A garage member told me that this was a common problem on the old Bosch KE-jetronic systems. The injectors would leak a little. A hot start was no problem, since not enough fuel had time to leak into the plenum. A cold start was no problem, since the leaked fuel had time to evaporate. But in between there was too much fuel entering the combustion chamber wetting the plugs and causing a too rich mixture.