Try this link with specifications for many of the old 3 wheelers:
http://www.files.3wheelerworld.com/pdfs/atcspecsreference.pdf
The optimal spark plug depends on your climate. I live in a cold country and use NGK BR6HS with a gap of 0,6-0,7 mm
Takes the same size as a 185. DR8ES-L
You need an 18 mm spark plug socket.
Dr8eix
Dr8es-l
NGK Brand spark plug # DPR8EA-9
if it is like my bike 2005 Honda foreman rubicon, you can find the spark plug under the seat. you have to take off the plastic part on the left side of the seat to acess the spark plug hole. by the way, the spark plug is very deep you probably need an extention, and a deep socket...
under the seat you have to take off a plastic tube on the upper left side to acess the spark plug.
it depends if it is wet then you will need to go to the dealership and get the factory spark plug and if this is not the problem take it to a shop to get it checked out or change and adjust the carbureator so that water or something doesnt get in there.
Same as anyother spark plug, 5/8 i think
The spark plug is inside the covers on the sides of the scooter on the left side. When you take the cover off, you should see an engine and on the left side a little wire going to the cylinder. This is the spark plug.
You take off the cap. Then pull out the spark plug. Put a new spark plug in. Then put the cap back on. Voila your done. Easy as pie!
Spark plug gap is where spark plug spark discharge is designed to take place. On a conventional spark plug, it is the area between the center and the ground electrode.