I have a '00 400ex and just installed a K&N Filtercharger and have plans for an add-on exhaust. Has anyone made similar mods? What should i jet the carb to and how do i go about this? Is it easy? any advice would be very appreciated!

PS i'm thinking about the powercore IV as an add-on. Good or Bad idea and any suggestions!

I live in Illinois and am unsure about elevations. I think jetting will help adjust for the High Flow filter.

Thanks for all your help!

Jera '00 400ex

 

Please help i can't do this on my own, there are 4000 members surely someone can help me!

Thanks you help is appreciated

Jera '00 400ex

 

sorry Jeaner wish I knew myself. I have been thinking of simalar mods. Hope someone knows. Good luck Mike

 

Jeaner, plug reading remains the most reliable tool for evaluating your carb jetting. You can read about this tuning technique in library books or on the Internet.

For example, http://www.icnetx.com/speed/jet.html
tells a lot "it" like it is in a few well-chosen words.

Resources like this URRL (there are others; unleash your search engine and see what you find!) and a shop manual for your ATV; at least get your friendly ATV dealership parts counterman to print you out an exploded parts diagram of your caruretor, will get you going.

I believe you must dump the float bowl to reach the main jet on your Keihin; then, no rocket science involved in removal and replacement of the main jet.

Good luck!

Tree Farmer

 

JEANER,
First of all, if you have an airport any where near you, call them & get the altitude at your location.
As for jetting, I would surely go one size fatter right now for the additional air flow you're getting with your filter change & if adding a pipe I'd go an additional size up for that.If the pipe is definitely an immediate investment, you might want to just go ahead & go two sizes fatter right now & possibly save doing it again soon, altho it is a no brainer to remove & replace the main jet. I'm a Warrior rider with a Mikuni carb, but I believe you have a Keihin & it should have a main jet access plug on the bottom of the bowl. Unscrew that plug with a 17mm (?) wrench to get to the main jet. Your dealer or cycle acessory shop should have a special little tool for removing the main jet..helpful but not required.It's about $5 & so are the main jets.If you do decide to go up two sizes before adding a pipe You could find that you are a little rich at the top end of the band but not a problem as far as any damage to the engine like running lean would be.Of course, in any jetting or other alterations, the final analysis lies in riding & testing.
As for pipes, the first thing you need to do is to decide where in the power band you want improvement. The next thing is to
learn which pipes are designed for that area...such as low to mid, mid to high, etc.
Feel free to e-mail me if you want more suggestions.

------------------
THE AZ HARD PACKER, calmiller@kachina.net

save the public land FOR you, not FROM you..join the Blue Ribbon Coalition online @ www.sharetrails.org



[This message has been edited by hot_shoe_cv (edited 11-22-1999).]

 

Re jetting the factory carb is a little tricky the first time.

The factory carb has plugs pressed in the needle adjustment hole and the pilot adjustment hole.Reason? Honda conforming to EPA emitions standards, And Honda not wanting smucks to easly mis adjust the settings and make the Honda look bad.Enough said.Next!

First step- Take the carb off the quad. It's easyer to work on.

Next- drill small holes in plugs.Skrew in "Shallow" oversized sheet metal skrew,Hold carb in one hand and grip head of skrew with vice grips and pull out plugs.

Next-Now you have access to adjust needle, And to change pilot jet.

Next-To change main jet you have to go inside, It's not that difficult. Just take your time on a nice clean bench.

Now for the settings.

With stock exaust and a new filter just bump up the main jet only.I beleave the stock main jet is a 133.You could bump up to about a145-150 max with the stock exaust.

With an aftermarket exaust the game changes.Depending on make and flow characterists of pipe.

For somthing like a big gun, For example, Then I would adjust the factory needle from stock setting of notch 3 to notch 5,Change pilot jet from stock 38 to a 40.Then change the main jet to a 150,And start your tests their.Ie-plug reading.

Install the carb back on the quad and test run. You must keep in mind that higher exaust output, Means that more air must be alowed to flow in!!!Hence the theory more in-- the more out.
So either drill holes in the airbox lid or leave the lid proped open.

Back to the testing..
You want to work your way up on the main jet setting during the tests.To find the pipes limitations.

On the first run, I would perdict that it would run great on the low end, Verry good in the mid section, But may "POP"(starve for fuel) wide open at the limiter.So work your way up in main jet sizes till it stops poping at the limiter.

Good luck.Check that plug!!!Should be a nice tan.I changed to a split fire.

My settings,
Dynojet needle on third notch.
Pilot changed from 38 to 42.
Main jet set at 170.
LRD- pipe and header.Holes in the air box with stock filter.

 

WOW! thanks to all! there are some great tips but i will admit i am not that mechanically inclined but would like to learn but i'm not sure if it is worth messing up my quad. is removing the carb necessary! i looked at it and it does look prety tight in there. What are the steps in doing this. do you recommend waiting until i get the exhaust so that this i somehting i only have to do once? or will the practice be good? how would i drain gas(might be a stupid ques. but i like to be safe rather than sorry) is each size jet a separate unit or is it an adjustment. i bet if i had the carb off it would make more sence.

Also i will prob wait until weekend to attempt this project and further imput would be nice. will running an aftermarket filter without jet adjustments be damaging to the engine?

I would like to say THANK YOU! the organizor of this forum deserves an award and so do all of the people out there willing to help someone they don't even know for whatever reason it might be.

keep the info flowing!

Happy riding to all----SAFETY FIRST-----

Jera '00 400ex

 

What all do you have to take off to get to the carb out. and how do you get the throtle cable out?

 

check the review of the biggun exhuast on off-road.com theres pictures and details of rejetting the carb. here's the adress http://www.off-road.com/atv/

 

Jeaner- Since you are somewhat new and don't want to do anything wrong, may I suggest you spend a little $ and buy the Honda Shop manual that will tell you all you need to know to get that carb out.

Look in the last few pages of you owners manual and there should be a phone # and part # of that Service Manual. I bought one and I think it was about $40.

Don't worry about hurting anything. Just use common sense, a good manual and this forum.

Good luck.