how come they never start in the winter?

[honda 400ex 69]

my 400ex never starts in the winter i get maybe 1 weekend worth of starting then it just wont start so i change the plug and it starts right up again whats wrong?


thanks for the help

[redrider ex]

mine is a 99 and it always starts but my buddy has a 2000 and he has the same problem all the time and we have the same mods and same jets .

[honda 400ex 69]

ya i have a 2000 too

[toby400ex]

some people jet theirs richer for the cold weather, but i dont think your problem would be from being too lean.:confused:

[timewass]

The reason people jet richer for colder weather is this:
Colder air is more dense. The denser the air, the more oxygen molecules get sucked into your cylinder. If you are sucking in more air simply because it is denser/colder air, then it is running more lean than if you were riding in warmer air.

[TravEX]

mine is VERY hard to start also, really only when it's below 40 degrees outside (jets in my sig),,,it's very frustrating!

[toby400ex]

the richer jet is almost like having the choke on all the time, since it is getting more gas, it isnt quite the extreme as the choke but it is noticeable.

[Steve-o 400EX]

Mine just turns over onece and fires right up.:p

Even after staying in an open garage when it is 10 degrees out.

[chad400ex]

I took my quad up into the mountains yesterday. It was about 30 degrees outside, but I figure the motor was really cold after a 45 minute drive in the back of my truck. I unloaded it, pumped the throttle 4 times, and hit the starter.... It cranked right up!!! I have NEVER had a problem starting mine. It did take a while to warm up, but after that it ran like a champ. 12 inches of fresh powder snow... It was a great ride.

[RideRed400EX]

What size tires do you run? A foot is a lot of snow for any sport bike.

[tom400ex]

i also have a 2000 and in the cold it take forever to start. and when it finally starts you can't even touch the gas or it just dies. i just leave it and let it idle for a few minutes.
why does that happen?

[RED121572]

Mine is a 2000. I bought mine in the winter of 99 and I was very disappointed that it took 10 minutes just to get it to run on its own.

Since then, ive up'ed a size pilot and that made things so much easier.

Oh, one little trick for ya.....turn the idol speed up, it helps alot.

[Steve-o 400EX]

Get a 42 pilot and try that. It will help big time. I got an 02 with no choke and a 42 pilot, i just pump the gas twice and it fires up faster than it did with the choke, stock.

[TRX300X]

Try pumping the gas a coupple times. Your carb has an accelerator pump on it and it will squirt fuel into the engine to richen it up. Do this before you try and start it.

[Syrus]

Muhahahahahahah my 250ex always starts no matter how cold, and i live in CANADA ! where its winter for half the fkin year :)

[infantry317]

You may need to turn up the idle using the thumbscrew and feather the gas as it warms up...Worked for me. Good luck!