my 1 year old Chinese still runs but...

[Tom999]

I've joined the forum last year and learned a lot about bikes.

I'm pretty much able to do most of maintenance work myself now and finally hit 10k on my odometer (2 months ago), a big suprise surprise for my little Chinese Lexmoto XTRs.

Last weekend I've changed air filter, cleaned carb, check the carb needle, de rusted exhaust, oiled the cables, changed the chain and made sure everything works fine. I still have to adjust clutch but that's for tomorrow

What happens/was happening last couple of months:

When I took the spark plug out it was covered in grease (oil?) this time, this never happened before, there have never been any oil/grease on spark plug. What could be the reason for that? Is that potentially showing signs of big time wear off inside the engine?

The bike dies a lot more often when it's cold, no amount of throttle is able to compensate the lose of revs and the bike just dies (typically at the junctions when I come to full stop)

On high speed roads, I'm not able to achieve the rocket luncher speed of 80kph (going downhill of course) as I did for the first six months, it feels like I'm losing a lot of power on the fifth gear (top gear) could that mean an issue with badly adjusted clutch lever?

Thanks for your opinions.

[Fozzie]

Wet spark plug?

Is it an oily brown?

If so your bike is running much too rich and needs the mixture adjusting. If you have a manual it will be stated in there, if not the member on here you will want is Rantmachine who has experience with Lexmoto carbs so will be able to shine more light on it.

Hopefully it's as simple as adjusting needle height, dropping it down to a thicker taper so that less fuel is mixed in the carb venturi.

Too rich or too lean is bad, you want your spark plug to be a slight off brown colour, not oily and wet. And if it's pale and white deposits you have it set too lean.

A bit fiddly but easily solved. Hard to actually know without seeing the bike.

[Grumpy Old Git]

I notice you have another thread on 'idling' issues - there is a very good chance these are related. You need to set up your carb correctly (mixture and idle) for the bike to perform properly.