My 2012 single spark seems to have developed a misfire. Starts at about 6-7k rpm and is far worse under load. Havent been using it much recently so whilst it isnt compleyely clean niether is it caked in crud. Anyone else experienced this? Is it likely to be a connection, coil pack, spark plug. Does one cylinder get affected more than the other? I'm assuming the horizontal one is the culprit given its location but can't see anything obvious.
It could be any of those things you list. Can I add air leaks on the inlet rubbers and faulty MAF sensor. Process of elimination.
MD Racing in Walton have just diagnosed it as a siezed exhaust valve. It had stuck briefly a couple of months ago but I hadn't thought anything more of it. Im Going to try and Un-stick it and clean up any corrosion as a temporary measure before resorting to buying an eliminator.
You know, that blo**y thing causes more trouble than it's worth! Having been a member of this forum for nearly 4 years I've seen the vast majority of poor running problems attributed to the exhaust valve in one way or another. The only cure is to get rid of the thing altogether!
If you are going to fiddle about trying to free the exhaust valve then just jam it open or remove the butterfly disc. Mine came pre siezed in the open position so im happy to leave it there until i get a decat.
So it was stiff but not seized (assume shop freed it up a bit). I have removed the disc from the spindle and left everything else in place for the moment. I noticed they tack weld the screws to the disc so had to drill one out.
