But it doesn't, it keeps stalling and turning the choke on makes no difference.


I took it in to the shop and they said that the inside of the carb was all discolored so they had to clean it up and it needed to be re-jetted, hopefully that will fix my problem.

Thanks to all,

Tom

 

Mine does the same thing as yours and mine has the same problem as yours...

You have a stock 38 pilot jet and so do I.

They are cold natured as hell when stock, and I think a little worse when you mod them. They fire, then die a few times on cold starts and will not take throttle a lot of times to keep it running.

What they need in most areas is a larger 40 or 42 pilot jet and the choke just removed... because they are a tad lean with the 38 I think.

This is a super easy thing to do on the 400EX carb.
I don't find jetting changes to be hard at all... just use only Kelhin jets.


Right now, I start mine like reconranger does... I pump the throttle a few times to prime it up and just start it. I never mess with my choke at all. If it's cold and the temps are cool it takes a few times to keep it going. I'll change my jets soon if I decide to keep it for sure.

 

I thought that mine was running a tad rich, the plug was black but it wasn't too bad, I'm @ 4500ft so that may have something to do with it.

My last 400 ran great with a pipe and filer w/o any rejetting but I guess 10 years may have contributed a bit to this ones problems.

 

The main jets are often a bit on the rich side for some folks and they do not need to re-jet for mods... and that elevation might be why.

 

I just purchased a trx 400ex. It is in great shape, however it sat for over a year. I had it tuned, new carb kit, oil, filter and tires. I drained gas and put new gas in. The shop that did this said it was running great, however it would stall at idle and they said it should clear after gas is drained and replaced. I did that and rode it for about 15 minutes and noticed the exhaust pipe at engine was getting red? It definetly was hot! Not knowing much about what it could be, and hoping someone can give me some ideas.

New to this.

JET

 

It will get red... normal.

 

Under normal riding conditions (not sitting still idling) you header pipe SHOULD NOT glow red.
If it does, you are running lean.

 

That doesn't sound good, I've never had my pipe glow red.

 

You boys never ride in the dark I guess... or you have stock headers still...

I know I'm not lean... I'm a bit rich... and mine will get red.
Gets really red when sitting still idling... no air flow and the pilot is only a 38.

 

It also backfires when it stalls or I shut it off. Could it be a valve issue?

Thanks for the help.