I tried to go riding the other day and my 400EX won't start. It cranks but will not turn over. It actually does this quite often when is very cold. It has a White Brothers rev kit, Big Gun pipe and a rejetted carb and I had heard that the WB rev kit makes it temperamental in the cold. Therefore, I changed it back to the stock one and still no luck. Any help would be appreciated.

 

Probably flooded from cranking by now... give it a rest. After a while, fully choke it and give it very little if not no throttle. See what happens. This is how my 400 starts cold.

-Matt

 

Just an idea, but this time of the year check your gas. I am sure that you have put a new plug in. In my area we have to buy gas with 10% methahol. Make sure that you are using 92 or better gas. This just some ideas. Best of luck.
Sunday it was so cool mine had to be pulled at the beginning of the day, started good the rest of the day.

 

Yep, the rev kit is the culprit (the rev box is designed for a kickstart motor, so it has a higher nessarsary RPM before the plug fires to prevent kickback). I'd recommend changing the plug/cleaning it, but you have to take the plastic off to even get at it. So, I suggest that you turn the choke off, then make sure all the switches are to run, get it to the top of a hill, or have someone tow you, and try to bump start it in a higher gear (3rd or up should be good).

 

I tried to tow it up the road four about two miles, but it only sputtered. Of course by that time it was probably completely flooded. I'll have to try again this weekend. Maybe push it in the garage to warm up first. The gas may be a problem also. I always run 93 octane, but it does have additives in the winter around here.

 

Why would you remove the plastic to change the cdi? The box is easily accesible from under the nose. Michiganredneck--What # pilot jet are you running? Try going to a #42 or #45 it will start much easier.I have and recommend selling the wb cdi. The only thing it gives is a few mph on top end from extra revs but at expense of hard starting and running the motor like a street bike. You can sell on Ebay and get $75-80.

 

Many people have reported hard starting problems in stock form as it is jetted lean from the factory. Couple that with the WB CDI and it makes it very hard to start in cold weather. I agree with mikeboone, you should sell the CDI box and up the pilot jet to a #42.

 

<< I'd recommend changing the plug/cleaning it, but you have to take the plastic off to even get at it. >>



You definitely do not have to remove plastic to change the plug. And that is probably the problem since you already said that you changed the rev box back to stock. It probably flooded in all your attempts to start it. Change the plug and try again.

 

Change the plug (you don't have to remove the plastic). Put a drop of drygas in your tank, pump the throttle three times and try that. Hope this helps.

 

A trick I used to use on my Banshee when it was cold is taking the spark plug out, and putting a drop or 2 of gas into the cylinder. WHen you hit the starter, the piston will come up, spark plug will fire, and the drop of gas will ignite, causing your whole system to start running. Good luck!