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400ex

  1. 2002 400ex throttle problems

    Honda TRX
    My 2002 trx400ex goes 1/2 throttle or 3/4 and then it bogs out. Sometimes it won’t even let my give it any throttle. I took the air box lid off and it helped so I put some holes in the lid. But it still did it after a little. Then I took the jets out and cleaned them. Could there be an...
  2. 2002 Trx400ex cutting out and dying

    Honda TRX
    I bought a 2002 400ex a few weeks ago and it will idle fine and as long as you don’t lay into the throttle too hard then you can shift through all the gears. When I hammer the throttle I can make it to about 2nd gear and then it cuts out and dies, it also has a little difficulty starting back up...
  3. 2003 Honda 400ex

    Honda TRX
    Recently bought a 400ex.. battery was zip tied to the battery cage.. went on a rough ride and felt the battery dangling by my leg, ground cable had broken off and once I put it back with the broken peice it didn’t crank no more.. but once I jump the start solenoid it cranks on but my electric...
  4. 02 400ex won’t start popping/backfiring

    Community Help
    Hello new to the forum and new to the Hondas sorry if I posted this in the wrong place but I need help, I recently purchased a 2002 400ex of a guy that could not get it to run. Currently it will only start when throttle is half open and it pops/backfires like crazy I trued full throttle one time...
  5. 400ex makes grinding sound then turns off

    Repair & Maintenance
    Ok so I just bought a 1999 400ex and it ran pretty good and then all the sudden I was riding it like locked down or somthing and I put it in the garage and it had other problems with spark and stuff so eventually I replaced all the wiring on it with a whole new wiring harness and everything and...
  6. 400ex makes a grinding noise after running

    Honda TRX
    Ok so I just bought a 1999 400ex and it ran pretty good and then all the sudden I was riding it like locked down or somthing and I put it in the garage and it had other problems with spark and stuff so eventually I replaced all the wiring on it with a whole new wiring harness and everything and...
  7. 400ex frame

    Repair & Maintenance
    Hey guys, I need a new frame for my 05 400ex. I have a friend who will give me a frame for an 01 400ex. Will my engine and stuff fit inside this older model frame?
  8. Need New Frame

    Repair & Maintenance
    Hey guys, I recently bent up the front of my 2005 trx400ex does anyone have a frame around or near Connecticut that they would sell me, if not does anyone know where i can get one for a good price?
  9. New to this site.. couple of questions

    New Member Introductions
    Hey, I just bought a 2005 400ex and am new to this site. I bought it with a brand new engine in it. I have a few questions about it. What is the best oil to run in it and is full synthetic ok for it or not? Also when its running it makes a small clicking sound coming from the engine, and im...
  10. Day at the Track

    ATV Media
    YouTube - Trx 400ex and 450r jumps
  11. Manual for 400ex trx

    ATV General Discussion
    Where can I find a manual online either pdf form or something. I'm trying to run wires, and trying to figure why the quad won't run.... thanks
  12. FS: 2001 400EX Parts

    ATV Parts for Sale
    Email with request and offer - entire bike going, plus extra parts. Local Pickup or shipping available with payment. Thanks guys!
  13. 300ex jetting(not quite right)

    Performance Modifications
    Alright i got my 300ex going a running good finally and i figured i would have to rejet so my brother had the stock jet out of his 400ex a 148 so just for kicks i put it in just to see how far off it would be. I did a plug check and its not far off. I have good throttle response good when i...
  14. 300ex motor question

    Repair & Maintenance
    Most of you are firmiliar with my quad and what i have done for those who dont I put a new crank in it. Now i have a question. The guy i baught it off of a.k.a. my brother now admits that he had the whole motor tore apart as far as i did and he lets just say had a couple extra pieces when he was...
  15. In need of all the help i can get

    Repair & Maintenance
    Ok i tore the whole motor down to cracking the cases and put in a crank i got out of a 2006 300ex because my rod bearings were boned. I put it all back togeather and started it up and it sounds great but when i try to shift it into gear its really hard to push down into first and it stalls...
  16. Selling my 300ex for a 400ex and cash.

    ATVs For Sale
    Im putting my 300ex up for sale pretty soon here and im really just wondering how much you guys think i could get out of it. Im really just lost about how much its worth. Its got all the seals and gaskets on the motor brand new, brand new stock bore high compression piston and rings, an amr...
  17. Rebuilding my 300ex need advice

    Repair & Maintenance
    Ok so im rebuilding my 300ex and i need some advice. Basically i wanna know how hard it would be to make it as fast as say a stock 400ex. Or if i would be better off parting out what i got and saving for a 400? I got alot of money in it already and i would rather build it and make it everything...
  18. 300ex cam change questions

    Repair & Maintenance
    K well just got my cam and rockers changed and i got a few quick questions. When you do this should u have to adjust the idle? and will i need 2 rejet?
  19. 400ex front A Arm Bushings

    Brakes & Suspension
    I am rebuilding my 2001 400ex and am having trouble replacing my front A Arm bushings. Do I need to take out the stock bearing before I put the new after market bushings in?
  20. 300ex cam replacement

    Repair & Maintenance
    Ok heres the deal i faught with my valves for a long time and finally got frustrated and ripped the valve cover off and saw that the rockers are toast and the cam is fried. Now i got a stage 2 web cam and hardened rockers real cheap and they look perfect. Got the rockers in and thats no big deal...
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