Mastiff with a not so mastiff spark!

[andyw]

Bikes been running right as rain since I bought it a few weeks back. try to start it the other morning, cranks over fine but no sign of it firing up
Put it down to low battery so next day after a night on the Optimate and...........same again!!

Neutral light shows
There's fuel (I can smell it after a few tries at starting)
........but found the spark (new spark plug) looked very weak and yellowish.

Looks like an ignition problem, where do I start?....new ignition coil? - advice appreciated
Thanks
Andy

[keithcross]

First off I would try again with hte old spark plug. New ones can be faulty. Other than that, does it have a spark? If so it might be a fuel problem. If not check all the connections for the igniton circuit.

Keith

[cat]

maybe the battery's died - although it's unlikely. check the connections at the ignition components. one by one, make sure they're tight and make sure they're clean. go through them one by one, clean with contact cleaner. if they look maybe a bit corroded, clean them with fine waterpaper.
and put the old spark plug back, like Keith says.
then report back. don't go buying new coils or anything just yet.

[andyw]

Thanks guys, the new sparkplug was fine for two weeks so don't think that's it, have replaced that with another new one anyway.

There is a spark but it looks really weak and it's yellowish rather than blue.

Fuel seems ok, crank the engine over a number of times and you get the smell of fuel. I've also pulled the fuel line and petrol flows.

Check all ignition connections - good tip, thanks.