[hondaquadquebec]

hello, after a lot of research I have not always found answers to my question so I decided to come and ask it here. I have a 400ex 2008 with the stock but no baffle and with a k&n air filter and a drycharger installed on the filter so i run without the airbox cover. I would like to know what would be the proper jetting for this machine for the mixture to be good.

 

[SlammedRanger]

There is more info needed to get you that info. Your altitude. And ambient air temp. I will warn you that taking the baffle out of your exhaust will do almost zero for performance gain. And will only agrivate the crap out of everyone around you. But with the rest of the information i can get you very close. Jetting can be different quad to quad but there is a degree of error that can still run and ride perfectly fine.

Welcome to the forums!

 

[hondaquadquebec]

Thanks you a lot so my altitude is 100ft and i run the quad in winter and a bit in summer so i don’t really know if i need to rejet the carb or not but because i run without the lid, should i rejet the carb?

 

[SlammedRanger]

42 pilot. I would figure main jet in the 155-160 range. Mixture around 2 - 2 1/2.

 

[diyer]

Check the color of the plug first.
Google reading spark plug colors.
This will tell you where to start.

I'm at 9200 feet and changed my main jet only.

 

[SlammedRanger]

Check the color of the plug first.
Google reading spark plug colors.
This will tell you where to start.

I'm at 9200 feet and changed my main jet only.

The reason you changed main jet only is your altitude. Higher altitude smaller jet. Heck your quad would have come with smaller jets from the factory if it was purchased locally. His quad being at a low altitude and being that he wants it to start in the winter will 100% need a 42 pilot jet. Or he will kill starters and batterys regularly. This carb limits the cold starting ability really bad. The fcr i put on my 400 makes it start in negative temps first turn and idle up to temp.

 

[diyer]

Question about pilot jet for my ATV.
ATV came from Arizona.
2003 Rincon 650.
Changed jets and cleaned carb.

Stock pilot jet with a 134 main.
9200 feet, Colorado mountains.
What pilot would you use?

 

[SlammedRanger]

With your altitude the stock pilot jet is probably about right. Could be a tad rich. Where is your mixture screw at in turns out from seat? If its in the lower 1s i would drop the pilot jet one size. High altitude is always really hard to tune for.

 

[diyer]

It runs good with stock pilot and 134 main.
It can be hard to start at cold temps like 0 to 20 degrees.
And it is probably a little rich on the idle circuit up here.

I'm no stranger to carbs. Raced 1/4 mile in the 70's.
I have an outboard, ATV, generator and snowblower that have been re jetted.

The cold start frustrates me when I need to plow snow with it.