Hi Guys

one of my 348´s has developed a strange problem.

With a new plug fitted (NGK BP5ES) the bike started and ran okay.

After about 1/2 an hour the plug broke down and it started misfirng.

Next time out with a new plug the same happend again after about 1 hour, strangely on the same climb (3rd gear pull). The plug showed it was running a bit rich but the plugs are duff as after cleaning and fitting to a good bike the bike ran but not 100 % and started misfiring after a few mins.??

To rich will kill plugs, cleaning wont change anything. Once they're dead they're dead.

Change condensor while your at it.

Edited January 7, 201412 yr by b40rt

Agreed - a rich mixture will foul any plug,the situation will be made even worse by a poor ignition system.

very good chance condensor breaking down causing weak intermitant spark causing unburnt fuel fouling plug worsening problem , id snip wire to condensor through hole in flywheel and use an old type beatle or mini or mg type wired to coil under tank to prevent getting hot

All the above comments are good. You need to clean up all potential grounds also.

Thanks for all advice !

First job will be the condensor, second need to get the tail pipe cleaned out as I think its restricting things.

I think this can this cause a rich mixture (to littel air passing through will richen ??).

What I dont exactly understand is why a (new) plug as b40RT (Ross) says after being once duff cant be cleaned and made usable again (but he´s correct as I had this with SWM´s in the past).

Zerorev3rev4 I also like the condenser under the tank as its not hot and easy to change so "will do" as you state.

Contrary to popular belief, condensors are not universal. There is a good bit of latitude in which will work in each case though. The condenser is there to prevent arcing across and burning of the points. If the condenser goes bad, there is a good chance that the points will have been affected. So, it is advisable to clean and adjust your points as well.