Mystery carbon pattern

[Howie]

Actually had five minutes to myself today, so I decided to strip my Kc100

I whipped the head off to check that all was well & found a lot of carbon deposited on the piston crown & the combustion chamber.

But whats foxed me was the strange 'swirly' pattern in the carbon on the piston crown

There is no damage to the barrel or head nor to the crown itself, I've never seen this before.

Anyone come across this before?

[500bernie]

Hi Howie,

How about a photo so we can all ponder and appreciate the phenomenon

Cheers,
Bernie

[Howie]

[img][img]http://i800.photobucket.com/albums/yy28 ... 001-17.jpg[/img][/img]

There you go Bernie.The picture doesn't really do it justice. I took this before cleaning the carbon off the piston. At first I thought maybe at some point a ring had broken & gone whizzing around the barrel, scoring the piston but the pattern is just in the carbon.

My only thought is maybe a ring had broken, scored the carbon & then the previous owner just replaced the rings & not done anything else
Or possibly a plug problem as the plug in the engine is relatively new

Bit of a mystery.

I'll be fitting a new piston/ring set when I rebuild the engine anyway but just had me wondering

[500bernie]

Hi Howie,
Not seen that before

I wonder what was going on to cause that

Cheers
Bernie

[375]

Looks pretty much a perfect circle.

Crop circle

Howie another bike how many you got now.

[headcoats]

What does the head look like ?

[Howie]

Crop circle

Howie another bike how many you got now.

Funny you should say that 375, I thought 'crop circle' as soon as I saw it.
As for my bike stock, I have 2 runners(mot etc) & about 5, possibly 6 in various stages of rebuild
It's not my fault, honestly

The head, is fine HC, lots of carbon but no damage or pitting, nowt
The engine has been split at some point (tell tale red gasket sealant everywhere ).
I honestly think it has shed a ring, part up, part down & a previous owner has just done what they had to, to get it running again

[Tambo]

Crop circle

Don't think it can be a burn patern - has to have been something mechanical to make it (I think ) If there's loads of sealant elsewhere, could it have squidged (not sure they'd accept that as a word on countdown ) a circle in from the head gasket, and then eventually burnt away ?

Tommy

[Charles]

Has your daughter been playing with it?

Charles

[maccas]

Is there a base gasket fitted?

Has the piston kissed the head?

Can't remember if the kc has a squish band style head or not, just seems as though there is no pattern in the centre of the piston.

Maccas

[headcoats]

Clean the carbon up and let's see what's underneath

[TwoStroke Institute]

But whats foxed me was the strange 'swirly' pattern in the carbon on the piston crown

Anyone come across this before?

Yes it's a message from the 2 Stroke Godsl

Says "Fix your friggin jetting"

[the_bard]

Yes it's a message from the 2 Stroke Godsl

Says "Fix your friggin jetting"

bahahahahahahaha love it!!!!!!