2008 te 510 starting problems

Hi there,
I have problems with my Te 510 - it won't start when hot. So here is an approximate problem description:
I can manage to start it when cold, every several days.
If it starts it runs well.
After running idle for 2-5 mins, if I kill the engine and will try to re-start it won't start. Everything sounds working, engine backfiring, but no start.

Things that I have checked and saw that they are ok:
Pump is priming and working. Suspected the pump problem at first, the fuel filter was full and pump was not spitting any gas when I took it off. So I replaced it with a new pump, bike started
but then the problem returned in a couple of days.

Kill switch is working apparently (because the pump is)

Battery is good.
Frame relays are good.
Remote ignition switch is good.
All ground wires are solid.

I did not run through all the wires, but all the harnesses have a lot of protection/isolation around them and they does not seems to be bad. I disconnected the head light and tail light connectors, just in case.

So I guess it leaves me with 3 items:
ignition coil
pick up
CDI

ignition coil has primary winding resistance according to the manual, but secondary is 20 Ohm, still I see spark on the plug every time I push the start switch.

I was told by a mechanic that it should be pick up, like it stops working when it warms up - but the resistance it has is good: 98 Ohm on cold, I tried to warm it with a fen for about 10 mins, then it was 108 Ohm . Still normal.

Any help would be appreciated.
Thank you and have a good day.
Igor.

Pull the spark plug after it has been running and then decides to not start. See if the plug is wet. I had a leaky head gasket and these same symptoms.

It is a little bit wet, no too much IMHO. It is logical since the engine is backfiring, isn't it? More dirt around the plug base actually than on the contact. (See pics.). I know that the plug is too black, and the head gasket is leaking outside - it was this way since I have bought the bike a year ago.
Pardon my ignorance, but why there should be a starting problem on the cold engine (now even after several days sitting it won't start) if the gasket is leaking? Just trying to understand.

Thank you

Here's what happened to my bike, it may or may not apply to yours:
I ran the coolant low, the engine got real hot, expanded the head, one of the head bolts got loose, that allowed some minor blow-by on the head gasket, then, coolant started entering the combustion chamber and making for hard starts when hot, after stopping during a ride, the coolant pressure would force coolant into the combustion chamber thru the damaged head gasket.

The condition of your plug would suggest oil is entering your combustion chamber.

The fact that you have an oil leak to the outside would tell me that your head bolts might be loose, and that there might be oil and/or coolant leaking into your combustion chamber. Get a new spark plug and check the spark before installing the new plug. It will most likely be fat and blue, and the bike will most likely start. Pull the plug often as it comes to temp, as it starts to fail and see what accumulates on the plug: oil or water.



This is an example of coolant entering the combustion chamber thru a damaged head gasket caused by a loose head bolt:

doesn't seems to be my case. my coolant level stays the same - just below the radiator cup.
although spark plug is kind of dirty/black - there was definitely no coolant on it.

thanks for your help though.

I did more tests: poured some fuel under the spark plug. then it seemed to be better starting .
so I took off the injector and saw that it sprays out the fuel and seems to be fine. still sprayed some carb cleaner into it.

but now all the sudden I'm getting another thing - no starter motor is turning. just hear the remote switch click and then nothing.
all fuses are intact.