[motoman691]

A customer brought me in this 400 EX. So he was riding and the spark plug blew out of the head. They did the right thing and replaced the head. But... Now trhey can get to start. So I double checked timing, Checked for spark and cleaned the carb. It turns over great and intermittently fires, But will not start. It acts like it wants too. I did get it to start 1 time and idle, but would not take any throttle. Thats why I thought maybe carb was dirty. Any Idea"s?

 

[SamUK]

Confirm timing is dead on.. Clean carb thoroughly, it has to be surgically clean, absolutely spotless..!! Clean fuel tank thoroughly, replace fuel line and add an inline filter. Set carb pilot screw/jet to 2 1/2 turns out from being lightly seated.
Replace spark plug for a new NGK.

Let us know how that works out for you.

DO NOT fit any China, Amazon/eBay parts.