need help 03 400ex first quad ever owned

[joe03400ex]

Hello all- I just purchased an 03 honda 400 ex and have not had much luck since I bought it. It came with a white brothers r4 slip on, k and n airfilter, not sure if its jetted or not-, skid plates and nerf bars- I'm going to jet it but not sure what jets to go with-, are there any "free" mods worth doing? I have already rebuilt the carrier, new chain and sprockets all oem. What type of maintenance should I keep up on besides air filter and oil changes? Previous owner said it sat for a year- it runs pretty good doesn't blow smoke but I hear the valves- is that normal? This is the first quad of my own and I would like to keep it in tip top shape all help would be greatly appreciated- I would also like to go a little faster without ruining its reliability what can I do?. Thanks all hope to hear back soon!-joe

[bigbad400]

free mods- remove choke add 42 pilot jet.

grind down welds on inside of exhaust header(right at the motor, very restrictive)

as far as valves, hondas you can hear them some but i would check them, and if it has an aftermarket cam thats prolly what your hearing not valves. intake .004 exhaust .005 if its in spec then your fine they do have somewhat of a tick even perfectly adjusted. nature of the beast.

keep the a arms greased and the swingarm pivot bolt, id take that out and greas it to if you can. definatly watch the rear bearings make sure they are greased regularly.

if you want more speed you should have got a diferent gear ratio, cheapest easiest way to add speed and not worry about reliability. dont know # of teeth, but if you go up one on the front it should be fine. i think 14 is stock for the front.

you definatly want a 42 pilot if you remove the choke, maybe go up 1 or 2 sizes from stock on the main, you dont have alot to rejet for, but if you spend a few bucks and get a aftermarket cdi, youll gain on top end nad it will feel so much more snappy, i got the AMR stg 2 coil and cdi. i love it.

also for 25 bucks and a gasket you can advance the timing 6 degrees, and thats alot more punch. i was also very impressed with that. its called a sparks timing advance key. ask around, good product.

and for my final bit of info, i was once told by some guy on here that you can do port polish, cam, big bore whatever, but really your not gonna be any faster than stock, upgrade your suspention and youll soar. if you cant take the bumps at 60 then at 80 youll just crash, but if you can take the bumps at 60 and at 80 youll be #1. keep that in mind. faster isnt always the way to go till your ride can handle it.

[sprayedgt]

I second the Spark timing Key. I think I got more of a power boost from that $25 part than I did from my $550 Yoshi exhaust. Going up one tooth on the front will give you more top end, but it's going to take away a lot from the bottom end. I have a 13 tooth front on my EX and it'll still get up to 60 on a long straight. Going any faster sounds all well and good, but on a four wheeler it's pretty scary when you get up to those speeds. Steering is VERY twitchy, any little bump nearly throws you off. Just not worth it. If you want to go fast get a get a dirt bike for that.