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gojk
03-24-2002, 09:51 PM
I have white smoke that comes out of my exhaust every since about the second time I changed my oil. It only does it when the bike is cold also. Once it is warmed up and running for a few minutes it doesn't do it. Also it only does it when I give it a little gas when it is warming up. Can anybody help with what might be going on. It is on a 400ex with a dyno jet kit with a 155 Main, Yoshi slip on, K&N Air filter and the choke removed and the headpipes gound out.

froggieboi
03-28-2002, 03:09 AM
That sounds pretty much like what mine does. I don't know why though. It would be nice to know.

03-30-2002, 05:26 PM
mine started blowing smoke like that went i neeeded a rebuild for my lakota
Sorry dude:(

TRX250XFIRE
04-02-2002, 04:25 AM
mine does to,but olny when its cold, everyone says my rings might be on the way of being fried

gojk
04-02-2002, 11:42 AM
What is the proper compression for a stock 400EX motor.

04-02-2002, 02:48 PM
My 400 did that too about 2 months after I got it one year ago. About a month ago I bored it. The rings and the cylinder wall looked perfect, but the vavle seals were hardened. I replaced them with Viton seals and the smoke disappeared. I would recommend replacing the seals first because more than likely your rings are fine. The Vitons also fit alot tighter on the valve stem. Just a thought!

gojk
04-02-2002, 02:52 PM
That is kewl cause I am gettin the 416 kit done prob in May and will have Marcum put the Viton seals in.

Scott
04-02-2002, 03:40 PM
You guys aren't talking about the moisture from the exhaust when the air outside is cold are you? THAT white cloud when you first start it up is condensation. Other than that, you shouldn't be able to make a 400 blow white smoke even if you wanted too. White is typically water, blue is oil, black is fuel.

gojk
04-02-2002, 03:43 PM
That is what I thought at first but the smoke doesn't disapate like the water vapor would. But that is what it kind of acts like.
And I have heard that is what makes the 400 so hard to start in the cold is the condesation in the engine. I am not sure though. The bike runs strong as ever so I am not worried.

250xman
04-02-2002, 08:39 PM
its the valve seals. i geruntee it. once it warms up the seals expand and it dissapears. replace the valve seal and your good to go.

twisted threads
04-08-2002, 02:08 PM
Scoot is right you guys, my 440ex does it when it is cold for just a few seconds then it is fine. One of my best friends 400ex does the same thing. If it is blue or black smoke and does not go away then I would be worried about it. But if you are worried about it maybe you should get it looked at better to be safe than sorry.