gunk
XS650 Enthusiast
Hey Freddy .Sorry to hear about your frustrating problem. Just a heads up. this summer I bought 5 boxes of NGK plugs
from a well known distributor I've dealt with for years Both for my RD400 and xs650c. Sometimes quality control problems hit.
Out of the 20 brand new plugs 5 were defective right out of the boxes. No signs of cracked porcelin or damage of any kind.
I was chasing my tail a bit as I automatically ruled out the new plugs. Have also had a new ngk resistor plug cap
that was n.f.g. out of the box . I am not trashing N.G.K. products in any way just to be clear as I have used their stuff for over 40 years before encountering this. I now ground each and every new plug on the fins and check for spark before threading them in. Found one more new defective one that way. Perhaps a new manufacturing plant somewhere or something I'm unaware of in the manufacturing process. Try slowly pulling the sparkplug cap up from the plug on the dead cylinder while the bike is running. Gloves would be a good bet to avoid a lifter. That's how I found the defective plug cap. The bike started to run on both cyls. when the cap was almost off the plug. Swapped the plugcap and the problem was gone. Also after checking all the wires and taking the advice of all the great folks trying to help out. Have You tried running it with the tank off the bike?
Sometimes over the years and owners wiring shifts ,moves,gets routed differently, chafes through and installing the tank can initiate said intermittent short when adding in engine vibes.Good luck.
from a well known distributor I've dealt with for years Both for my RD400 and xs650c. Sometimes quality control problems hit.
Out of the 20 brand new plugs 5 were defective right out of the boxes. No signs of cracked porcelin or damage of any kind.
I was chasing my tail a bit as I automatically ruled out the new plugs. Have also had a new ngk resistor plug cap
that was n.f.g. out of the box . I am not trashing N.G.K. products in any way just to be clear as I have used their stuff for over 40 years before encountering this. I now ground each and every new plug on the fins and check for spark before threading them in. Found one more new defective one that way. Perhaps a new manufacturing plant somewhere or something I'm unaware of in the manufacturing process. Try slowly pulling the sparkplug cap up from the plug on the dead cylinder while the bike is running. Gloves would be a good bet to avoid a lifter. That's how I found the defective plug cap. The bike started to run on both cyls. when the cap was almost off the plug. Swapped the plugcap and the problem was gone. Also after checking all the wires and taking the advice of all the great folks trying to help out. Have You tried running it with the tank off the bike?
Sometimes over the years and owners wiring shifts ,moves,gets routed differently, chafes through and installing the tank can initiate said intermittent short when adding in engine vibes.Good luck.