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400ex

  1. ATV General Discussion
    I purchased an 02 400ex a few months ago without any paperwork for the quad. Had my buddies father run the vin (he’s an nypd officer) and it came back clean. I also payed to have it ran online multiple times. Anyway, I know it isn’t reported stolen, so that’s out the way lol. I really wanna get...
  2. Honda TRX
    TL;DR: 400ex runs for a little, maybe a minute or so and then stops dead like the engine has locked up. You can (with some force) get it unlocked by turning it over by hand and then it seems to turn over fine. If you start it, the whole process repeats. I have a 400ex that I'm trying to get...
  3. Repair & Maintenance
    Hi I have a 400ex that I recently put a 2005 450r carb on. It runs good awesome throttle response and power but I have one problem. At wide open throttle it pulls hard almost all the way to the rev limiter but when it's almost there it dies and is really hard to start again. It runs good for...
  4. Repair & Maintenance
    Hi I have a 400ex that I recently put a 2005 450r carb on. It runs good awesome throttle response and power but I have one problem. At wide open throttle it pulls hard almost all the way to the rev limiter but when it's almost there it dies and is really hard to start again. It runs good for...
  5. Honda TRX
    Hello all, I am new to owning and working on Honda ATVs. I recently purchased a 2001 400 EX. The previous owner lost the keys and instead of just ordering a new one he spliced the wires together. I did verify it was not stolen via getting the title from him. Anyway, I ordered the new ignition...
  6. Honda TRX
    My 07 Trx400ex cannot start in neutral without the clutch being pulled. The fuses are good, there are these 2 unconnected wires though. They say N and R for what I assume Neutral and Reverse but I couldn’t find the other end that wasn’t connected. Do these connectors not plug in any where. If...
  7. Honda TRX
    I have a 2002 400ex bored to 416 with stage 2 hotcam, ECO Big Gun exhaust, stock carb, and stock intake. I was wondering if I should get bigger jets and open my intake some more. It runs good now, a little rich but I was looking for more power if I could. I don’t have much knowledge on intake...
  8. Honda TRX
    Hi, I'm new to the forums. I just recently traded my foreman for a trx400ex. I have a ton of experience with quads and any with with engines, but never a sport quad. The problem I'm having is the quad runs flawless for a while, but when I do a wheelie in 2nd and sometimes 3rd, it starts to...
  9. ATV General Discussion
    I have a Trx400ex I rode it one day and it stoped and the back wheels locked up I have since inspected the head and piston and crank which all seems to be fine it turns over but slowly any suggestions on what it could be
  10. New Member Introductions
    Hi I have a Trx400ex. Drove it down the road and the back wheels locked up and it won’t start up again . I have striped it down and the piston and head and the crank seem to be okay any suggestions what’s wrong all help appreciated
  11. Repair & Maintenance
    How’s it going fellas? So I have an 02 400ex and last Saturday about four hours into riding I noticed that when I was at WOT it wouldn’t really come up in the RPM and seemed to stay steady at roughly 3-5k RPM. It happened randomly and I can’t figure out why. Has this happened to anyone else...
  12. Performance Modifications
    I only trail ride and I’m looking to get a little more juice out of the 400ex on a bit of a budget, I was thinking of leaving it a stock bore, I have a big gun eco r slip on, and stock everything else, I was thinking of throwing a new stock bore piston in it just to freshen it up for the season...
  13. ATV General Discussion
    I picked up a 2001 400ex a while ago and I was told it was completely stock, I put a big gun muffler on it and rejetted it. Recently it started to burn some oil so I decided to take it apart to rebuild it and I found out it had a Webcam 450/451 cam in it and everything else is stock I was...
  14. Honda TRX
    Hello all. New person here. I have a 2008 400ex that I recently put an hmf slip on exhaust on along with a uni air filter and removed the airbox lid and snorkel. Hmf recommended a 42 pilot jet and 175-180 main jet with this set up. After installing a 42 pilot and 180 main I adjusted the mixture...
  15. Repair & Maintenance
    My husband and I have 400ex that we bought a few months ago and it wants to bog down whenever you go to get on the throttle. It idles fine, he has replaced the Jets, then bought a new carburator all together, CDI Box, coils, all he can think of, and it still doing the same thing. It runs fine...
  16. Repair & Maintenance
    Just wandering if the ignition switch from a 300ex will hook up to a 400ex?
  17. Repair & Maintenance
    It’s an 2002 trx 400ex Been bored to 440. Has hmf exhaust it will crank but won’t run. U have to give it 1/4 throttle for it to run but then it’s loud and the timing is right every single time. I’ve changed ever electrical part cam new battery changed the fly wheel took the head off checked the...
  18. Repair & Maintenance
    The gasket kits are different due to reverse components, I get, but are the crankcase covers any different? For example, will a 2002 right and left side cover fit on a 2007 crankcase? Will only the left cover work? What are the differences between motor components between these two groups of...
  19. Repair & Maintenance
    Hi guys I have a 2006 400ex. I’m doing a clutch replacement, and it’s never once been opened up. I have tried everything from hitting it with an impact hammer to a crow bar on the fin, and nothing will take it out. The cover is just stuck. Can I have some help with what to do? Thankyou guys!
  20. Repair & Maintenance
    ok so basically at first machine did this thing were jut would run and just quit and quit but what we didn’t know is that it want getting oil so it pretty much blew it up and i got a brand new top end professionally done so it was done right and i brought it home and it’s kind of doing the same...
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