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400ex
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  1. New Member Introductions
    Bought my son a 2005 400ex has been running great but now right after a fill up it has a dead spot in the throttle and no power. I check for contaminated fuel and cleaned the carb. I'm lost since it has. Been running great till now
  2. ATV General Discussion
    I'm currently building a 426 with +1 valves kibble white valve springs ported and polished head stage 2 webcam with a 11:1 je piston and working on trying to find a 04-05 450r carb. Is there anything else someone would recommend doing while I'm already in it or has anyone had a similar build if...
  3. Honda TRX
    Hi everyone, I’ve got an 03 440ex with a ton of mods and I love it to death, but I haven’t ridden her in a while, just had some starting issues that I’m getting annoyed with. My starter used to work perfectly fine, but then one day it started slipping a little. It’ll crank, then just spin free...
  4. Repair & Maintenance
    Hey, decided to start this cause these forums helped me along the way on my rebuild. I just rebuilt the top end on my 400ex and it runs a ton better now, only problem is that it’s smoking from the exhaust port on the new head I replaced. I’m thinking it’s because of the old crushed exhaust rings...
  5. Repair & Maintenance
    I would really it if someone could take a photo under the fuel tank of a 2008 Trx 400ex so I can see how to reinstall the plate air guide (floppy black rubber mat) between fuel tank and the heat protector plate.
  6. Repair & Maintenance
    I’m am currently looking at buying a 2003 400ex and was informed it needs a new flywheel and starter bearing I am mechanically inclined but more on auto and motorcycles . I’m wondering how much of a pain this repair is and really how I would go about narrowing it down to this issue actually …...
  7. Performance Modifications
    Hey guys I’ve got a 400ex with a high comp piston and different cam and my stock starter won’t turn the motor over and my battery and electrical is all good. I switched to a higher cca battery thinking it would help but it didn’t. And before my motor work was done the starter would turn the...
  8. New Member Introductions
    Hello I'm new to the forum so I hope you all can help I have a 2000 400ex and I'm wanting to do a few mods but I am on a budget......I'd like to find a longer swing arm and a set of a arms to widen the front if I can find any that are fairly cheap ......I'm interested in any mod parts and...
  9. Repair & Maintenance
    Hey guys you can call me stupid if you want but about 5 months back I took my 400ex apart to pull the motor and have it rebuilt and I took the plastic heat shield that goes in-between the gas tank and the head of the motor. I can’t remember what the 2 bolts look like that hold the tray on...
  10. Performance Modifications
    I just picked up a used sparks header off eBay for 95 dollars but it doesn’t have the silencer with it and I don’t want to spend 730 dollars for a new one so I was wondering what silencer will fit with the header? I already have a hmf slip on but I don’t know if that’s compatible to use with it...
  11. ATV General Discussion
    Hi, I recently bought a 2005 Honda TRX400EX and I love it. I have gotten to know it pretty well in the time I have had it. The one thing I am not sure how to use (or maybe is broken) is the parking brake. Can anyone show / tell me how to use it? Images would help also. Thanks in advance.
  12. Repair & Maintenance
    ‘00 trx400ex, it’s air cooled. Bike gets hot after about 8-10 minutes of riding. Doesn’t matter if it’s a light ride or full throttle. No oil leaks (anymore lol) but sometimes it does gets so hot oil starts pushing up out of the head. Can’t figure out why it’s over heating
  13. Honda TRX
    Does anyone have recommendations on what main jet and pilot jet I should use on my 05 400ex. This is my first quad and doing research on what other people are running on their pilot and main jet is confusing to me due to people running a range from 170 to 185. It is running 416 big bore kit...
  14. Repair & Maintenance
    Honda ‘00 TRX400EX; go for a short ride, like 8 minutes running time, bike smells hot and there’s oil coming from somewhere above crankcase. checked dipstick before leaving house and it’s dead center between min and max
  15. Honda TRX
    So over the winter I replaced the valve seals and top end of my 400ex because it was burning a lot of oil and smoking. It now has a 11:1 compression piston. It’s running good now for the most part but has a tick. I replaced the timing chain hoping it was the problem but still ticks and tensioner...
  16. ATV General Discussion
    Figured out.
  17. 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...
  18. 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...
  19. 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...
  20. 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...
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