don't rejet?

[Stevie-D]

i went to the dealor today for diferent jets, and the one guy told me that i shouldnt have to rejet from the stock setting, even with the WB pipe on it. i told him that i kept fouling plugs and that the plugs are wet when i remove them...which means that its running a bit rich. he told me that its only happening cuz the ex aint supposed to be run in the cold and it wasnt meant for that:confused: so i bought a diferent plug that he suggested. he told me to try it and call him back with the results. he also told me to hook it up to a charger when i try to start it. is it true about the jetting?i dont think so. what do you think?:confused:

[GNCC#829]

A parts guy told you that? Go ask the service guy. I am positive he will give you the exact opposite answer. 400ex's are cold blooded, but that doesn't mean you cant run it in the cold, it means that it is not jetted for the cold.

[Stevie-D]

thats what i thought...if its fouling plugs its too rich right?

[GNCC#829]

In the winter it runs too lean, Air is more dense. So I'm not sure about the fouling plugs part. Someone else will have to answer that.

[Stevie-D]

its strange, but the plug seems to make a diference. i ran it on the roads for over 3 hours today, and the 400EX is running better than it ever has:rolleyes:

[wgbanks]

Strange..... is parts guy not wanting to sell you something. No, that just ain't right.:huh

[brian400ex]

I know that my bike will usually start up ok when cold, but if it doesn't fire up right away the plug is usually wet and black. But once it is running good the plug has good color. So you may thought that you were running rich but it may have been the cold weather affecting the bike. If it does it again just clean the plug. And it will fire right up. Hope this helps.

Brian

[wgbanks]

C&D have a great tech tip on jetting. Here is the link. http://colbykostman.tripod.com/id57.htm

[roostu]

Bottom line....if your bike was jetted properly before you put on the pipe, you need to re jet after the pipe is installed, because it will change the way the motor runs.

~Roost-U

[Stevie-D]

I know that my bike will usually start up ok when cold, but if it doesn't fire up right away the plug is usually wet and black. But once it is running good the plug has good color. So you may thought that you were running rich but it may have been the cold weather affecting the bike. If it does it again just clean the plug. And it will fire right up. Hope this helps.
i think that you are definately right. it fired right up with a different plug, and it ran the best it ever has.:D im gonna get it out in a while, and ill see how its running today

[Newbie400ex]

I think that sales guy is full of crap. I put on an e-series silencer,ground the header welds,K&N filter,and modded the airbox lid but I kept the stock jetting just to see. It ran a little better. Then I went ahead and changed the main jet to a Dynojet DJ170. The difference was very noticeable. The front end is lifting out of the corners now. Much better with the jet change. I think even a stock 400ex could benefit from a jet change.

[tprender]

What you have experenced in a good example of a service person who 1) don't like quads and2) doesn't know **** about jetting. Like someone said the 400 comes from the factory running lean. If you go up a few sizes on the main jet from stock it will run better. This shows that he knows nothing about 400's. and anytime that you let the exhaust flow better you need to increase the jetting some.
Very good for asking for a 2nd opinion before doing what he said. I like the part best about hooking up to a battery charger to get it started. It sounds like you have a plug that was or had been fouled out from not starting and it was time for a new plug.

[SuperEX]

Originally posted by Newbie400ex
I think that sales guy is full of crap. I put on an e-series silencer,ground the header welds,K&N filter,and modded the airbox lid but I kept the stock jetting just to see. It ran a little better. Then I went ahead and changed the main jet to a Dynojet DJ170. The difference was very noticeable. The front end is lifting out of the corners now. Much better with the jet change. I think even a stock 400ex could benefit from a jet change.

I went through the same thing, There is a big difference now.
But before I rejetted I also went to my local dealer and the parts guy looked at me like I was crazy and said I shouldn't change the jetting. But needless to say I changed it.

[Leo]

the parts guy didn't want to go through the hassle fo finding a $3 part probably..

Leo

[Stevie-D]

i doubt it. the sales guy checked, and there were no jets in stock, but he offered to order some for me. i dont think the jetting is off. its running great now. strange.
the guy owns 2 400ex's, so i doubt that he is that nieve about the jetting:chinese: