GPZ bang and now cylinder won't fire

[dn38416]

Hi,

Issues with this bike are becoming more frequent. I recently went into a garage and they turned the idle speed up for us. But i noticed a tapping noise from the right hand side of the engine, like this:
https://youtu.be/yqSBBRIlVpU

(actually it's very feint in that vid). It didn't really increase in frequency with the throttle much, but was only ever really noticeable while the throttle was open.

Anyway so go to start the bike tonight, stick the choke on and just get a loud bang, a flash and then smoke. Only the left hand cylinder runs, and the other side stays cold.

Any ideas?

It's stuck in a car park at work now, if it's just a simple part outside of the engine that needs replacing i can probably take some tools there and replace it. I probably only need it for another 6 months before i replace it. Bike only has 44k miles on it, which i understand is not so much for these engines.

[Riejufixing]

Engine doesn't sound good. Was the bang & flash electrical, or otherwise?

[dn38416]

Yeah my guess is electrical. The flash i thought came from just between the fairing and top of the engine. The smoke cleared pretty quickly and didn't carry on (but like i say the rhs of the engine stayed stone cold).

[jaffa90]

Time to remove fairing/s and get a sniffer dog with specs.

[stinkwheel]

Is the sparkplug still in? Plugcap still on and in one piece?

Could have popped the resistor in the plug cap. Not entirely unheard of for a plug to unscrew itself too.

Also worth visually inspecting the ignition coil.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[RhynoCZ]

[Riejufixing]

[misscrabstick]

I think the spark plug has been loose for ages and it's now blown out it's hole.

[dn38416]

Ah sorry for delayed reply.

Basically i woos'ed out and just called in someone to get it back to the garage. If it was a question of just replacing a part i could have done it there, but i got too much on and dislike the train too much, i just need it sorted.

My money's on the coil - only because of the flash (if it was the plug dunno if i would have seen that). But i when i powered it up again today it sounded like something was blowing as well.

New spark plugs went in a couple of months ago, and i changed over the caps about a year ago. Just screwed them in hand tight.

Will let you know how deaded it is.

[Shaft]

[dn38416]

That's pretty compelling tbf. When you say blown out, you mean it has worked itself loose over time, or stripped the threads in some way as it's come out?

Only thinking the latter is probably a lot of work to correct.

[Shaft]