Misfiring bike

[dubber68]

Well my bike went in for a valve check and since then it has been misfiring when under load. The bike is a g650gs sertao and I am due to be heading off to Nordkapp on it very soon. My gut tells me that something has been disturbed when doing the valve check, maybe a coil or something. What do you guys think? I will be contacting the dealer unless it is something I can fix easily enough myself.

[mechanic]

Tight valves, excessive plug gap, coil breaking down under load, air leak if some pipes not correctly replaced after recent work, leak on egr system for example. Hope this helps you. Nige.

[Magnon]

I’d always go for the last thing that was changed so wouldn’t be surprised if the garage messed up the valve clearances but they would have had to remove the sparkplug so it wouldn’t surprise me if they damaged it or even fitted a different/wrong one.

[steve the grease]

Having been in the motor trade far more .... Too long actually , I have always found the question " So, what happened last?" to be a very valuable diagnostic aid. Eg ' Oh , I've just filled it up with petrol......, oh look it says DERV on the bill'.
On this occasion its a typical case of ' Dealer repair'. Otherwise known as ' Who gives a shit' or 'Oh it's only the valve clearances , the apprentice can do it ' Cue someone who looks like Plug out of the Beano comic, only less intelligent. Dealers, you couldn't make it up......... Take it back, quick , before the cylinder head falls off or something.

[dubber68]

The dealer did a valve check but said they were in spec so I assume no shims were swapped etc. I certainly wasn't charged for valve adjustment. I was however slightly worried when at the time of booking the valve check I was told to be there an hour early to allow the bike to cool. I however insisted the check should be done cold and that the bike would be dropped off the day before. I have done some web research which can be both helpful and misleading and a trapped/damaged kill switch wire can give the same symptoms. The kill switch wire and connector could both potentially be disturbed when gaining access to the cylinder head and rerouted incorrectly when reassembling. I will have a quick check of this before trusting the dealer again.

[dubber68]

Well when I started to strip the bike down to check things over this morning I discovered that the positive connection on the battery had been threaded from over-tightening. This has to be removed to get to the cylinder head so probably a lapse when putting everything back together. New battery to order then see if the problem has gone away as these bikes are very sensitive to battery connection faults.

[dubber68]

Well new battery fitted and problem solved. Glad it was something simple.