The engine's been starting pretty well in warmer summer months but a bit "chuggy" in winter.
Here's what came out of no.4 cylinder

The fact it doesn't say Made in Japan probably means they're inferior copies.
The electrode has actually fallen out - so it must either still be in the precombustion chamber of been VERY lucky and spat out the exhaust

Does anyone have a clear photo of a Bongo cylinder head combustion chamber so I can see the size of the flame hole?
