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Falco's developed a misfire on the way home tonight. Was running fine for the first 5 miles (albeit slow due to traffic), started popping when coming back on from a closed throttle. Steadily got worse the further I rode, last bit getting home was quite bad.

Anyone any thought's as to what it is? I'm hoping it was just the heat, that said it shouldn't happen so is it indicative of something starting to fail? I was messing around looking for this camchain adjuster, so possible I've upset something? But was fine in the morning. Only things I disconnected (and thought I'd reconnected OK) are the crankcase breather (I think - pipe from rear cylinder into bottom of airbox), the big white plug next to the fuel quick release, and I think that was it!

Tomorrow morning will be interesting... especially at 7am if it starts popping!

When I say bad, I don't mean was affecting the ride, just a loud pop that could be felt through the bike, not juddering and affecting the drive. Seems fine when gassing it, just that roll-on, roll-off point

Check the thin sensor wires that touch the front cylinder head on the left side near those pipes you were messing with. The plastic coating wears out and they short circuit which screws things right up.

I'll second HisNibbs diagnosis. I had exact same symptoms and always got worse as engine got hotter. Finlly traced to wires as described. They branch from main loom and go to sensor at top of the rear cylinder. Mine now insulated with old bicycle inner tube and no problems since.

Hi all.

I concur, this fault happened too me, causing misfire and cut-outs when slow and cornering! Just re-insulate wire

Hope you find the problem quickly...

Sussed it! After poking round the hoses, wiring, and everything else on the LHS, I thought that one of the plug caps was loose, so made sure they were all down tight, jumped on the bike and went up the road.

Now, I always ride in leathers, but as I was only test riding, I jumped on with my jacket and just some combat trousers. A mile up the road when the popping was still there, I thought that the back of my thigh was getting rather warm.

So pulled up at home, started running my hand over the exhausts to see where the heat was coming from. No problems, no problems, up the header and, what's that hole? Oh wait, isn't there usually a plug in there?

So, anyone got a spare gas sensor plug they can send me over? I need to check with Griff, cos they had to drill one out so need to check the size first.

Guess it's the car tomorrow...

I was actually going to mention the sensor plug, as that happened to me as well (i.e. one falling out), but as the consensus seemed to be a wiring issue I didn't mention it.

Let me know your address and I'll pop one in the post to you - I bought a few when I discovered they were a standard size plumbing/hydraulic fitting available for about a quid or so each. 1/8" BSP, as I remember.

Here's a thread about a thread...

https://www.ridersite.com/viewtopic.ph ... c&start=15

Thanks mango, but if they're easily available I'll grab one tomorrow at the local shop. Thanks for the offer anyway

One last question - the parts diagrams show a washer, is this needed? I assumed it depends on the type of plug used.

And if it is, what material? (Copper?)

Ta

PS Mango, have sent you a PM, struggling to get out to the shops to pick one up (work getting in the way), if the offer still stands would appreciate one sent over. Thank you