wr 426 backfiring
Posted January 01, 2008 - 12:27 AM
my mate was told it was proberly because the exhaust was so restricted from stock so he put an fmf power core rear muffler on it, and removed the airbox top cover, checked the jetting on the carby and it was all stocked, checked timing all ok, he replaced the plug and ran fine but after a couple of rides and letting it sit for a week or two it would be hard to start again and run rough with the throttle open backfiring untill u rev the shit out of it and ride hard for a few minutes then its fine for the day, till next ride.
when it's backfiring he replaced the plug straight away and bike starts first kick and doesnt miss a beat till you let it sit for two weeks and after a couple of rides.
He has put a iridium plug in his bike but it still does it, if any one could help it would be great thanks
Posted January 01, 2008 - 07:57 AM
Posted January 02, 2008 - 02:34 AM
i have almost the same problem with my 426 -02.
i have yoshimura full system and removed removed the airbox-top, the jetting is stock and my bike runs great for 30minuits and after that its backfiring when i´m in gear and accelerating but no problems when idiling or reving in neutral. if i replace the plug it runs great for 30min and then its the same problem again. when i replace the plug it is black.
(i hope you can understand my english)
Posted January 02, 2008 - 04:13 PM
Posted January 02, 2008 - 04:18 PM
Posted January 02, 2008 - 10:21 PM
Posted January 07, 2008 - 03:07 PM
Traced it to a bad connection between the spark plug cap and the lead going to the plug cap. This was after six months of stuffing around with jetting!!! Hope it helps.