7 Nov 06
I don't know a lot about bikes but I think the spark plug only comes into play at the initial turning on or kicking over of the engine. Spark plugs do not do anything once the engine is running so I would say your problem is else where, maybe you have a blockage in your fuel line.
• United States
22 Feb 07
I have to disagree. I've encountered numerous times an engine (especially a 2-stroke) that would indeed start, but either would run erratic and/or quit, due to a "fouled" spark plug. I've built and repaired thousands of engines, and trust me, a spark plug can fire intermediately or not at all even after the engine has started. One case in point, I built and own the current MRA's Fastest Moped of the Year '06, and because of the really filmy oil that I use (Redline full synthetic), it does foul the plug quite frequently. If/when it begins to run poorly, I can replace the spark plug and it runs fantastic again. Anyway, there could also be other electrical issues with this particular bike, including the possibility as mentioned of the coil breaking down, an arc to ground from the high tension lead, faulty plug boot, etc., etc. The spark plug just so happens to be probably the cheapest and easiest thing to replace and eliminate as the culprit first. Just trying to help.
• United States
21 Feb 07
If you are pretty sure that it is losing spark, check the obvious first. Replace the spark plug with the same type and number, and also check the spark plug boot. Hope this helps. I know this post is a few months old, but I just got here. It'd also help to have more details of the bike, such as make, model, year, etc.