oz thumper Posted October 30, 2007 Report Share Posted October 30, 2007 (edited) Well here is the latest we have checked every single electrical connection and cleaned them all adjusted the valves cleaned everything we could see and reach with a cloth someone suggested that we hold the throttle wide open and kick it 3 times (which i guess re starts the computer) the bike still back fires and the plug is still black running rich you can even see it running rich with black smoke coming out of the pipe any more ideas I don't normally reply to a topic that I don't have personal experience of, however offer the following thoughts. My 05 always ran rich and would foul plugs regularly, after checking all readings we eventually swapped all components systematically with a mates bike (Painfull process). In my case nothing changed until we swapped the throttle body and then the bike was completely different. I obtained a new throttle body and that bike has been fine ever since. I reckon in this case though I think you have two different things going on running rich should not give significant backfiring on the over run, in fact it is normally a sign of a weak mixture or an air leak. On carburreted bikes at the shop backfiring through the exhaust on the over run was always traced either to an air leak in the exhaust or a burnt exhaust valve (as others have noted). Now the bit I am not sure of is with an injected motor is it possible for a faulty injector to dribble rather than cut off clean after injection (this is common with diesel motors) I would guess a small amount of fuel getting into the cylinder could produce ignition when the exhaust valve was open? Personally would still see the most likely cause of backfiring to be an airleak and probably at the barrel to pipe joint, have you cleaned out that area and put new seal in?? Good luck Edited October 30, 2007 by oz thumper Quote Link to comment Share on other sites More sharing options...
hannon Posted November 3, 2007 Author Report Share Posted November 3, 2007 well thanks for everyones input here is the final words "exhaust leak" one of the header to cylinder bolts was loose tighten it down and the backfire stopped Quote Link to comment Share on other sites More sharing options...
munch Posted November 3, 2007 Report Share Posted November 3, 2007 thank you Quote Link to comment Share on other sites More sharing options...
big john Posted November 3, 2007 Report Share Posted November 3, 2007 well thanks for everyones inputhere is the final words "exhaust leak" one of the header to cylinder bolts was loose tighten it down and the backfire stopped Only just picked up on this thread, that is a common four-stroke trait, if cold air is drawn into the exhaust at the manifold on any four-stroke, it tends to cause an explosion in the exhaust system, only on the "over-run"! Big John Quote Link to comment Share on other sites More sharing options...
nigel dabster Posted November 3, 2007 Report Share Posted November 3, 2007 thank you Well m sport strikes again, perhaps if you can diagnose faults instantainously from a forum perhaps you can answer this, when the are 2008 4rts landing in the UK. Quote Link to comment Share on other sites More sharing options...
munch Posted November 4, 2007 Report Share Posted November 4, 2007 soon Quote Link to comment Share on other sites More sharing options...
perce Posted November 4, 2007 Report Share Posted November 4, 2007 (edited) soon free beer tomorrow Edited November 4, 2007 by PERCE Quote Link to comment Share on other sites More sharing options...
munch Posted November 5, 2007 Report Share Posted November 5, 2007 he doesnt drink Quote Link to comment Share on other sites More sharing options...
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