2015 YBR125 loss power and burnt out spark plug

[bazzaboy2010]

I experienced a loss of power after reaching 30 mph. Once I got home, I inspected my bike, removing the filter and so on, until I came to the spark plug. As you can see from the picture, it was burnt out. I only serviced it four weeks ago. So, my concern is why this happened and whether there might now be a problem with components in my engine.

[pdg]

That's been exceedingly hot (thanks, captain obvious)...

Possible cause is a lean mixture, what air filter are you running and how long has it, and that plug, been in there?

The immediate concern would be the missing porcelain - that stuff doesn't melt... If you're lucky it shattered into tiny pieces and got ejected out of the exhaust, or if you're slightly less lucky they're rattling around in the cylinder or embedded in the top of the piston.
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Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

Also, the gasket doesn't look like the plug was tightened correctly, or it's supposed to have a taper seat plug - are you sure it's the right plug for your bike?
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[WD Forte]

The recommended plug from 2008 to 2018 is the NGK CR6HSA which isn't a tapered seat type.

what type is the one in the pic? ( I think I can see 'CR6' on the body)
Are you telling us this went from a new plug to this within one month?
age of bike?
mileage?

'Service' can mean running a damp rag over it onwards
and doesn't tell us much.

Reasons/guesses:
long time neglect
cheap copy plug mebbe?
As the ECU does all the timing and fuel mixture stuff, bad sensor readings may cause it to miscalculate those things
Any fault codes flashing up?
Does the eml light come on briefly at switch on then go out?
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bikers smell of wee

[pdg]

[WD Forte]

Be interested in how the threads in the head look.
Cross thread a steel plug in an alloy head and the plug wins every time.
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bikers smell of wee

[stinkwheel]

I'd be worried about how the piston crown looks based on that. Might even be able to see with a torch?
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“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[WD Forte]

wouldn't be surprised if you caught a glimpse of the con rod too
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bikers smell of wee

[bazzaboy2010]

[bazzaboy2010]

[pdg]

Well, it doesn't specify what plug it is, but I can definitely see "CR6" stamped on the one in your photo...


This is making me have thoughts.

Thought 1 is that seems an expensive service kit, but that's by the by.

As for the plug, there's a few possibilities, some of which have been mentioned but I'll type them again. Could be one of them or a combination.

Counterfeit plug.
Butchered installation.
Damaged plug before installation, either in transit or after delivery.


What did you set/check the plug gap to?

Can you provide a picture of the threads in the head?
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[Fullers1845]

Where did you get the plug? There are counterfeit NGK's all over places like eBay, I returned one last year as it was so obviously a snide one.
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Honda CB125F, Kawasaki ZX6R J1, 1922 Sheffield-Henderson Blackburne grasstrack/sprint

[pdg]

[bazzaboy2010]

[bazzaboy2010]

[pdg]

The hex on that plug is really damaged - was it hard to remove?
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[pdg]

Also, that plug doesn't look entirely on the up and up, the printing just looks 'wrong'...

NGK plugs usually have very clear and solid lettering - that's a bit fuzzy for my liking.
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[bazzaboy2010]

[pdg]

See how this looks different?
____________________
Any and all advice given should not be followed - if you have to ask it means you don't know so get a man in to do it for you.

[MCN]

Two options.

Option 01 (real option.)

Invest in a big bit.

Get a top-end gasket kit.
Whip the heid aff it.
Inspect the cylinder head internal surface, inlet outlet valves, piston crown and cylinder bore.
Although to be sure the engine requires complete disassembly for inspection, to eliminate any unseen debris cratering the enginebin short time if not thoroughly investigated.

Option 2. (Only bodgers need apply)

Find the correct plug spec.
Buy a couple of new plugs from a reputable supplier.

I use an outfit called.

The green sparkplug company for all the plugs I replace.

https://www.gsparkplug.com/

They also provide advice if you contact them.

Good people.

Also, look for a plug upgrade while you are at it.

Iridium plugs are very nice at sparking.

Pick any 5hite out of the plug hole.
Bang in a new plug.
Pay attention to the torque procedure for the plug.

If you fit a new plug that has a crush washer, the plug it torqued by turning a specific amount.
If the plug is later removed, then the plug needs a revised torque.
I'm not spending my data explaining here.

Sparkplug Sockets use a ghey numerical identification system known only to pedants.

It needs some investigation before wasting good money on sockets you do not have plugs to fit.
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Disclaimer: The comments above may be predicted text and not necessarily the opinion of MCN.

[A100man]

I call snide..

https://www.ngkntk.com/newsroom/blog/emea/fake-or-not/
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Now: A100, GT250A, XJ598, FZ750

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600

[Fullers1845]

[pdg]

[MCN]

[pdg]