Kx 125 wont start

change the plug then drain the carb and ck compression and that will tell u the story

muffler bearings definately

32:1--40:1 any less than 40:1 And you take risk of damaging engine(crank and top end),Any more than 32:1 and it will smoke real bad and foul spark plugs alot.....

I can give you reccomended Team Green setting for your weight, dirt bike setting are usually based on weight,

unfortunately apart from removing the lights you wont turn it into a MX bike, new expantion chamber,porting and suspension mods are all quite expensive, just try and learn as much as you can as it is(minus lights)

Well if it looks like that picture, it's a dirt bike, not legal for street use. If it has head lights and blinkers, it is a dual sport. The engine size is stamped into the head. Like .125 liter or .250 liter. I think the dual sport is a KZ and the dirt bike is KX. That is Kawasaki.

There is no actual oil filter on your bike. The oil gets dirty and you change it. That is the only "filter" for the oil in your bike.

VIN:JKAKXWR12PA008201
World region:Asia
Manufactured in:Japan
Year:1993
Make:Kawasaki
Model:KX80-R
Body style:Moto Cross
Drive type:RWD
Cylinders:1 Cylinders

sounds like the rings are fried and needs a new piston and rings.. for an 80 there about 110 bucks for the whole kit