What is the spark plug size for yz 250 - 2003 Yamaha YZ 250

SOURCE: 2001 yz 426 spark plug

Remove plug then reinsert top cap only let plug hang free now kick over starter wile somone watches the plug for spark (the darker the better!)

SOURCE: what spark plug for yz 125?

I have a dennis kirk book, the correct spark plug is a --BR9ES--(NGK)

i always used SAE 10w-30 oil on all my dirtbikes,
no transmission fluid

for the chain you should move the back tire back until the chain is at a snug tension

SOURCE: no spark on 1986 yamaha 250 yz

ok now first check if you have power to the coil with a volt metre

SOURCE: i have a yamaha yz 250 98' and wont start i

coil

SOURCE: the yz 250 1986 has the same engine as the tri z

im not that good with carborators so any help will be great .