I've had a few xtx and R's and have sorted most things out but this has me stumped. my xtx is backfiring at about every 3-4 seconds at say 2000rpm. I have tried swapping parts like a different injector, spark plug, coil and cap, new fuel, charged battery, but still its playing up. just wondering if this could be a result of a bad key in the stator?

any comments appreciated guys!

I wonder if it would pay to check the ignition pickup under the alternator cover.
They call it the crank position sensor, I think. You disconnect the plug in the loom with (for the Tenere, at least) the blue&yellow/green&white wires, and check the resistance. It's about 200 ohms.

We have trouble with these on our work bikes, and the symptoms range from those you describe to complete no-go.

They aren't a service item, and must be replaced with the stator unless you have a competent motorbike electrician who stocks these critters and can splice a new one into the system.

I'll second that. They can fail completely (which is easier to identify), but they do quite often shake loose and cause erratic crank pulse signals with consequent ignition woes, weird misfires and random non-starting.

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thanks so much for the informative replies mates! I suspect that this could be the problem and will sort it out in the next couple of days. Luckily I have a spare engine here so parts wont be a problem (no decent bike shops in the Philippines and ebay takes so long with tax to pay when items arrive!)...

An unrelated thing was my mate showed up on one of my old xtx's with a bad knock in the engine last month. wasnt backfiring but was noisy. turned out this was the counterweight key. I had the same problem on the old xt and tt 600 models. I've seen damage from a key shattering at 100kmph, it smashed a hole in the top of the engine big enough put a hand in!