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killing plugs
Posted: Sat Oct 17, 2009 8:31 pm
by jackpot
anyone any ideas why i keep killing spark plugs,and not just one make of plug,2 last week and 1 today after about 25 miles.they're still sparking but with about 3 sparks going back into the plug and not jumping the gap,HELP PLEASE
Re: killing plugs
Posted: Sat Oct 17, 2009 8:35 pm
by J1MS
possibly detonation, and its cracking the porcelain insulator.
Re: killing plugs
Posted: Sat Oct 17, 2009 8:48 pm
by jackpot
J1MS wrote:possibly detonation, and its cracking the porcelain insulator.
should cracks be visible ?,plugs look mint.it's running rich on the bottom end but surely that can't cause it[it goes back up to dans next sat] at this rate i'll need 3 or 4 plugs to get there
Re: killing plugs
Posted: Sat Oct 17, 2009 9:13 pm
by J1MS
jackpot wrote:J1MS wrote:possibly detonation, and its cracking the porcelain insulator.
should cracks be visible ?,plugs look mint.it's running rich on the bottom end but surely that can't cause it[it goes back up to dans next sat] at this rate i'll need 3 or 4 plugs to get there
No there not normally visible unless the insulator shatters at some point, my guess is if its just a little bit of detonation & the scooter is possibly a little rich. Then the plug tracks to earth inside the insulator giving a very insufficient spark at the tip till it doesn't spark except through the insulator, then it cuts out or just fails to kick up after you stop.
This really is only a guess and I'm not even sure its whats wrong with yours, just a possibility... I'm sure Dan will put it right, whatever the problem is...
Re: killing plugs
Posted: Sat Oct 17, 2009 9:49 pm
by jackpot
forgot to mention plugs only ever die at junctions or when starting ,never when riding under load if you know what i mean ?
Re: killing plugs
Posted: Sat Oct 17, 2009 9:53 pm
by sean brady scooters
wrong grade plugs,thats all.
Re: killing plugs
Posted: Sat Oct 17, 2009 10:00 pm
by jackpot
sean brady scooters wrote:wrong grade plugs,thats all.
ngk 8,ngk9,nippon denso forget the number without going in garage but the correct equivalent,they can't all be wrong ?
Re: killing plugs
Posted: Sat Oct 17, 2009 10:10 pm
by Andy Pickering
Would it be something like faulty CDI, faulty stator sending to much power as in a surge and the weakest link being the plug..bit like a light bulb blowing after power surge..?
Re: killing plugs
Posted: Sat Oct 17, 2009 10:12 pm
by J1MS
You could try gaping the plug down to a very small gap, about 12 thou and see if it helps, if it does then its possibly a weak spark, Dan is possibly right, maybe wrong plug grade might be the problem.
But as I said, I am only guessing, and I'm probably miles off with my guesses...
Re: killing plugs
Posted: Sat Oct 17, 2009 10:51 pm
by red
3 vapor speedos ,then 3 spark plugs!!
What's next?
Not cranks as you've already done more than 3
