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Sooted Spark Plug.
Posted: Fri May 01, 2015 7:06 pm
by bogie
Can anyone out there explain why my spark plug gets badly sooted enough to stop the engine.It is running a standard plug, a new air filter,
the Carb needle was dropped a notch, The bike ticks over nicely and picks up the drive smoothly, no lumpy running associated with richness.
I have heard it said that unleaded petrol can cause it. the bike is an 05 plate Bullet 350 I have fitted a new exhaust pipe and a cigar
shaped silencer in place of the original and taken the breather from the catch can and routed the pipe to above the chain. Normally it is
a joy to ride but with this problem it is a pain. Has anyone out there encountered this problem if so perhaps they would let me know the cause
please.
Sooted Spark Plug.
Posted: Fri May 01, 2015 7:42 pm
by PeteF
Its not unknown for people to get the choke lever in the wrong position. Down is off on the 350
Sooted Spark Plug.
Posted: Fri May 01, 2015 8:05 pm
by bogie
Sorry, I have fitted a conversion to cable operation and if it is not pushed back into the off position the engine will 8 stroke
and emit a lot off smoke.Thanks for your reply
Sooted Spark Plug.
Posted: Fri May 01, 2015 8:23 pm
by Frank
Stale petrol can cause rich running but if the problem has only arisen post the new silencer an exhaust pipe then I would start there. Normally a more open pipe would cause weaker running but perhaps the mixture was richened to compensate for a previous exhaust set up and now you have a more restrictive one, if you do,it is too rich. Plug grade and float height are possibilities too.
Sooted Spark Plug.
Posted: Fri May 01, 2015 9:10 pm
by Lennie
Too much fuel, or not enough air,. Fuel side: check fuel height within float chamber, check float not punctured or sticking, air side: check there are no obstructions to the free passage of air into the combustion chamber.
Sooted Spark Plug.
Posted: Sat May 02, 2015 6:52 am
by Gwilly
Bogie are you sure that the cable conversion is allowing the enricher to return FULLY to its off position, not lifting slightly when you turn the handlebars side to side..
Be worth checking that it seats properly, maybe even disconnect for test.
Sooted Spark Plug.
Posted: Sat May 02, 2015 11:27 am
by bogie
Hi,
thanks everyone for your replies I have learned a lot from them and will follow them up.
I will let you know in due course the outcome.
Bogie.
Sooted Spark Plug.
Posted: Fri May 15, 2015 7:52 pm
by bogie
Further to my earlier missive I have checked a few things, the one thing that did show
was the float height. this appeared to be a bit on the high side and would cause rich running.
I have corrected it and hope it is a cure. I will come back when I have given it a run.
Bogie.
Sooted Spark Plug.
Posted: Fri May 15, 2015 9:00 pm
by ric
An enrichener if not fully seated can result in an AFR of around 8:1. Damhik. Definitely worth double checking.
Sooted Spark Plug.
Posted: Fri May 15, 2015 10:13 pm
by Beezabryan
Please enlighten me, what is an AFR and also a Damhik?