So what do we think caused this on Harrys TZR50 yesterday ? had to go and rescue him with the trailer after his bike stopped on the main road ....................In his words it suddenly lost power then cut out............ upon investigation I found the spark plug bridged by something that appeared to be welded across electrodes ................... bike still had normal compression and looking in the plug hole the top of the piston looked in very good condition as far as I can see. Put a replacement plug in and bike seems to sound and run as normal.
So any of you two smoke fans .........what do you think? ..............imminent melt down or nothing to worry about

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

Methinks Harry should carry a spare plug and plug spanner iike wot all yoof used to Only way home from the pub when underaged drinking in days of yore.

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I'm a Hornithologist, I get excited by exotic birds.........

Biggest problem is all the plastics that make what should be simple tasks take an age to check ...long live naked bikes

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

Strikes me that he's been thrashing the tits off it

Looks like it might like a grade harder plug Is the timing bang on? I don't think it's a mixture problem, but this is just a guess

I think the thrashing theory is far more likely

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If your dreams don't scare you, they are not big enough.

I did jet it up a few weeks ago because it seemed a bit weak ........... wasn't sure what's been done to it but found it had already got a 92 main jet instead of the standard 88 (now running 96)......... since realised that somebody has removed a cone from the expansion chamber inlet and I think maybe changed the ecu some how because apparently standard they only rev to about 7K this one revs to about 10500 ............or off the clock downhill according to H so I think the thrash the tits off it could possibly be correct

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

Like father like son

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Buell Ulysses XB12X 06/08

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IF IT BLEEDS WE CAN KILL IT ,THIS STUFF WILL MAKE YOU A GODDAM SEXUAL TYRANASURUS ,YOUVE BEEN PUSHING TOO MANY PENCILS DILLON .GET TO THE CHOPPER

It was probably a drop of aluminium that got through the air filter then took a fancy to the electrode gap...

I would get a borescope down there and look for signs of erosion on the crown and head...

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08 Specialized Langster

I would if I had access to one

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2001 X1 2009 1125CR 2006 Uly X3 2010 Uly a fully Maz'd S1 and a 1991 RS1200 Westwind.

As it's a stink wheel, it'd be a lot easier just to whip the lid off and have a peek at the crown. Like Pash said, it may some contamination from the piston skirt etc that's been pushed through the inlet port

(Because he's been thrashing it )

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If your dreams don't scare you, they are not big enough.

I was being fasicious when I mentioned the air filter, the bottom line is it has come from somewhere in the engine...

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08 Specialized Langster

Stage 1 tuning for 16yr olds in this neck of the woods, is ripping out the air filter

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If your dreams don't scare you, they are not big enough.

Used to be called Plug Whiskering and was a common phenomenom in "petroil" days.
Not sure if anyone really knew what caused it but often put down to type of oil used and sometimes petrol used. Have you used a different oil recently or filled up from a different garage? Never known it to cause any damage so I wouldn't worry unduly. Carry a spare plug and spanner and put it down to "Character"!!!

Try hotter plug or iridium one, better to run rich than lean, take exhaust off look in hole at side and bottom of piston, if it still has good compression I wouldn't worry too much about it, I had rd350s for 10 years before I got a buell, no going back now lol

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Ride it like you've stolen it