by the way, we ran the lrd full and were very pleased.

 

You will lose performance if you use (octane boost or AV gas) without the compression necessary for those fuels and additives.It sounds like a gearing change would be the cheapest way to go for what you are looking for.Imroper jetting could be slowing you down on the top end if you are too rich so you may want to look into that.If you can afford it the LTE dual performs very well on the ex but i have seen good performance from the white brothers as well.

 

if u want more speed the only way to get it is changing the gearing. i dont know how people can be so stupid to think that more hp makes a quad have a higher top speed. if the motor runs out of rpms, putting a pipe on it just makes it get to that rpm faster. and all of the stock 400s ive been on have been able to rap out no problem. unless you plan on getting into the motor its not worth buying anything else.

 

Sounds like your really wanting internal engine mods, but are somehow afraid of doin them.

A good cam, a litle porting, and a few other little things will make a really large difference.

I wouldnt bother with going to a new pipe since the one you have can easilly handle the power you will be making so save your $$$ for other mods

 

get a 16 tooth front

 

Curious what you decided on doing?

 

a cam is good and my macanic put a 440 kit in his ex and kept it at 10.1 so he runs it on 93 octan pump gas and a rev box is good to

 

hey man, ive been racing dirtbikes and got bored with that and i bought a 2001 400ex, ive got skid plates,nerf bars and tires thats about it i was wondering what i needed 2 get next. thanx

 

I have been thinking about starting a thread to address the various mods avail for the 400ex, and then break it down into sections from basic safety and comfort mods (nerfs, skids, handle bars, grips etc) to three levels of performance up to all out no budget fun (basics like pipe, intake, and air box to hi comp pistons, big bores, suspension etc) but there is so much involved to do it correctly I was waiting until I found some time LOL

I know there are several threads in here already that deal with most mods for the ex, and there is a big bore one that I either started or added onto etc, plus a whole lot more on other sites as well.

Maybe try searching 400ex and a mod your considering "400ex pipe" or 400ex piston" and if your even considering a larger bore try "416 , 440, 416ex etc, and then find your way to the better threads where you will get more info.

If you have a more specific question you dont see answered I cant see a problem posting it here since this thread is titled 400ex help.

 

One more thought on how to answer the question of what to do next.

Before you can get serious you first have to look at two or three things, What can you spend, what areas are you most interested in improving, how much of the work can you do yourself, and very importantly be sure that your looking at parts or mods that will work with or enhance what you have now.

Even though many believe that slapping on a high flowing aftermarket pipe on stock machine may sound cool, it may not give much if any increase in performance without a few other mods to allow it to work right. If your looking at a pipe you also have to consider a new higer flowing intake (K&N?) modding or removing the air box lid, and changing the jetting to compensate for all the extra air the engine can now flow.

And except for the absolute most basic mods you will want to include what has been done to date so that the people trying to help wont have to guess at what you have.