ok so this morning i go to start my 400ex and it wont, it will crank, but it will not turn over. it did for a minute then it died, and now it wont start, it just cranks untill the battery is dead. we thought it might be the battery so we went a bought a new one, and it still does the same thing. my dad wants to change the plug, but he doesnt know the plug size to get it out. can anyone give me any more suggestions on what it would be or the plug socket size?

 

Use the wrench in the tool kit.

 

It is a 18mm but a regular socket won't work it will have to be turned down, or it won't fit down in the head. You should be able to go to a local shop and they should be able to get you a sparkplug wrench for your machine.

 

its used, i just got it, so i dont have the tool kit, but i heard a 18mm thin walled socket would do it, is your 400ex hard to start in the cold?

 

I actualy sold mine and I have a 04 z400 now, but to answer your question yes mine was hard to start in cold weather. The previous owner had removed the choke on mine and had it jetted alittle on the rich side. I finally figured out to give it full throttle one time and then crank it, and usualy this would work for mine.

 

yeah ive tried that. it still doesnt fire, im going to get the valves adjusted [it ticks], replace the plug, and probabally put a hotter CDI in. i think that should help.

 

If your valves are too tight it will keep it from starting, but me and my brother has tried to adjust the valves on a ex we can never get the ticking out of them