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SOHC.co.uk Forums => CB500/550 => Topic started by: mickwinf on June 16, 2022, 11:53:03 AM

Title: duff spark plug
Post by: mickwinf on June 16, 2022, 11:53:03 AM
Had a morning off today so thought i would take my 550f2 for a cheeky spin, the first outing this year! so checked the tyres etc and started it up, but only fired on 3 cyls, no 3 not sparking. of course its awkward to remove but tried it on the side of the engine and sure enough dead as a dodo. Ok so plugs do wear out but i have had this problem before with my 500/550 bikes, where after being stood for a while and even if it was running fine when last used, one plug decides not to play. I always use NGK and have very few miles on them so what is the answer, do i change brand?
Title: Re: duff spark plug
Post by: paul G on June 16, 2022, 12:52:16 PM
Are you sure they are genuine NGK a lot of copies out there. ;)
Title: Re: duff spark plug
Post by: K2-K6 on June 16, 2022, 01:01:17 PM
Have you tried that #3 on a lead from #4 to see if there's any different interaction (maybe a problem on #3 supply routing) just to eliminate bike based compromise.

I very rarely find a faulty NGK plug across cars, bikes and small engines, that's even after severe flooding too as they always seem to survive to spark again  :)

Not knowingly had a imitation plug but have also heard stories that they're about.
Title: Re: duff spark plug
Post by: Oddjob on June 16, 2022, 01:39:03 PM
Yeah I'd suspect the HT lead or cap before the plug Mick.
Title: Re: duff spark plug
Post by: mickwinf on June 17, 2022, 08:53:07 AM
I have always bought my plugs from silvers so hope they are genuine ngk. The plug caps are new and the lead has been trimmed to make a good connection, and all i did was put another plug in and away she went. Its not a big deal but a bit odd.
Title: Re: duff spark plug
Post by: Bryanj on June 17, 2022, 08:55:41 AM
I would go to your local motor factors mate, probably sell more and cheaper
Title: Re: duff spark plug
Post by: Oddjob on June 17, 2022, 01:04:33 PM
I'm trying ND plugs this time around. Bought a box full when they were cheap.
Title: Re: duff spark plug
Post by: Orcade-Ian on June 17, 2022, 05:18:56 PM
I bought a box of 10 NGK a while ago from fleabay and fitted 4 of them to my classic Mini Estate, which has a late Cooper injection power unit.  All fine for a good while then started playing up like a bad king lead to the dizzy - except it doesn't have one! Tried a spare coil pack - no different.  Would accelerate smoothly up to the red line as long as you were gentle but if you asked too much in too high a gear, it would buck like it suddenly had no sparks on any cylinder - so much so that it buggered the top engine steady rubbers   Bought a set of Bosch plugs from our local factors and it was back to its old self.  Yes, there were fake NGKs out there - I binned the rest, lesson learned.

Ian
Title: Re: duff spark plug
Post by: Yoshi823 on June 20, 2022, 03:11:56 PM
I bought some NGK plugs from M&P for the Exup & had problems with 2 of them within a 1000 miles

(https://i.postimg.cc/GphxGYBS/20200522-153132.jpg) (https://postimg.cc/PC9DkCQm)
Title: Re: duff spark plug
Post by: Matt_Harrington on June 20, 2022, 06:45:51 PM
So much for those plugs being reliable! I thought the VX ones were meant to be one of the better plugs....
Matt
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