Quantcast
Jump to content

  • Join Today, It's Simple and FREE!

    As a member, you can post in our forums, upload your photos and videos, use and contribute to our downloads, create your own member page, add your ATV events, and even start your own ATV club to host your own club forum and gallery.  Registration is fast and you can even login with social network accounts to sync your profiles and content.

zx6r

2000 Honda 400 EX Exhaust Smoking

Recommended Posts

First off im new here so hello to everybody, second a friend of mine has a 2000 400 ex that i am thinking about getting, and it was smoking really bad so we tore it down and the cylinder looked fine but the exhaust valv:huh:e had about a 1/8 inch of something that looked like carbon buildup but was white on it, could this be from burning oil , do u think it needs valve seats or seals or maybe just a set of rings, it runs fine just smokes and uses about a quart of oil in 8 hrs, thanks guys

Share this post


Link to post
Share on other sites


it probibly need a set of rings ... i have a 400ex motor that u use for racing and hill climbing that has done the same thing several times ... the oil ging looses it's tension and compresses into the oil ring grove on the piston ... i bought a heavy duty set of rings and put in mine and it lasted twice as long b 4 it needed rings again..the 400ex runs hot ... even from the factory and the stock jetting is a little on the lean side in most cases.. a little jetting will help with it running as hot ... i have 2 400ex's and 4 extra motors that i keep ready for a swap incase i need 1 ... i ride my machines pretty hard .. if the bore of the machine your are talking about is in good shape i would re ring it and see how it is .. also while u have ot apart you could put valve seals in it fairly easy .. an kill 2 bird with 1 stone .. so to say ... lol... if you have any more quastions about the 400ex just ask .. i have rebuilt many of the 400ex motors and have come across all kinds of things with them .. :yes:

Share this post


Link to post
Share on other sites

Ok thanks for the info man, are there any weakpoints or common problems to look for with an ex?

Share this post


Link to post
Share on other sites

the only real issue i have had with any of mine is the oil ring... and the rear axle bearings ... but thats pretty much it as far as running and riding ... :laugh:

Share this post


Link to post
Share on other sites


I think that is right on, probably leaking oil past the rings, the white ashy deposit is normal and is an indication that the exhaust valve is sealing and holding compression.

Share this post


Link to post
Share on other sites

* Adjusted thread title to include issue and model year

Share this post


Link to post
Share on other sites
First off im new here so hello to everybody, second a friend of mine has a 2000 400 ex that i am thinking about getting, and it was smoking really bad so we tore it down and the cylinder looked fine but the exhaust valv:huh:e had about a 1/8 inch of something that looked like carbon buildup but was white on it, could this be from burning oil , do u think it needs valve seats or seals or maybe just a set of rings, it runs fine just smokes and uses about a quart of oil in 8 hrs, thanks guys

if i was you i would have head cleaned and have new value seals and bonnetts changed dont go half assed.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Similar Topics

    • By AimlessMoto
      Hey guys, new here, but haven't found ANY answer to my specific problem on a Suzuki dedicated ATV forum, so here's to hoping!
      I acquired a 95' Quadrunner 250, 4x4, (LT4WD) for practically nothing with no spark. The PO had tossed in a used stator which didn't fix the problem... so I went all routes (though cheaply) to narrow down the initial problem of no spark. 
      Plug, coil, CDI (caltric) and stator w/pickup (caltric) were purchased and installed. And it RAN, but bogged horribly and would not rev past 1/4 throttle. 
      I checked fuel flow, vacuum lines, all the normal stuff, no issues. I decided to check the valves and cam... well, there was one problem. The cam was 1mm under the lowest spec in the manual. So, in-came a new cam, Stage 1 Hotcams... also threw in a new set of shindy valves, lapped them, replaced the valve seals, and the timing chain. 
      Back together again (w/stock airbox and new oiled filter). Now it idles even better, still boggs at 1/4 throttle, but will rev past it if you hold the throttle open for a second. Ahaha... success!
      So I was able to ride it above 1/4 throttle once I had momentum... could shift through the gears, all was good as long as I kept it over 1/2 throttle. Took a long enough ride to break in the cam properly at least so I won't have to worry about that. 
      Now, I start fiddling with the carb. It's clean as a whistle, stock, with stock jets (new replacement Mikuni jets). Same problem. 
       
      I start thinking, maybe this is fuel related and the bike is having an issue transitioning from idle jet to main jet... so I LOWER the needle by raising the clip 1 spot. Now it revvs up in neutral with no bog, but it boggs about the same trying to ride it. So I move the needle down again with the clip on the top slot. Better, but still has a bit of bog at 1/4 throttle. 
      The last bit of advice I got was to ditch the CV carb... so I sprung for a brand new Mikuni VM30-83 round-slide. Bolted it up, blew into the vacuum tube to fill it with fuel (no vacuum port on this one) and she fired right up... but there is still a bit of bog, it's just masked by the fact that I'm not waiting for the vacuum diaphragm to open. 
       
      So I feel like each little step brings me closer, but not perfect. I'm now wondering if this is still in-fact a carb tuning issue (I have some jets I can fiddle with and maybe lean-out the idle jet a little.) OR if the cheap-a** Caltric Stator/Pickup is what's causing these issues. 
       
      I have a 95' KingQuad with 400 miles on it... like new.. runs like a top... I've tried both the stock QR and the Caltric CDI boxes on it, and it revvs up and runs like a champ. 
       
      The only unknowns between the two systems are the carb, and the stator/pickup. My next step in troubleshooting is to rip apart the King Quad and test it's CDI on the Quadrunner... but considering there is no change to how it runs I doubt it will lead to a solution. 
       
      HOWEVER... I tried the stock CDI just recently after running the Caltric this whole time, and the bike runs like garbage. Hardly idles, and won't rev up at all. So, that is my one smoking gun telling me that it's either the pickup coil or the stator itself. 
       
      Has anyone had a problem even CLOSE to this? I can't image the carb would be causing this many issues, especially going to 2 different ones, both with stock jetting to OEM, and exhibiting the identical symptoms... the only change is when different CDI's are plugged in, or when the needle valve leans out the mixture. 
      Also, I checked the piston, rings and bore when I had it apart and they're like-new... no scoring, rings are loose, cylinder is still round and has honing marks still int he bore. Stock piston, stock bore size and it has 160psi compression. Battery is brand new, and I've tried 3 different R/R's, none of which change any symptoms, but slightly vary the charging voltage by .2-.5 of a volt depending on which unit. Also tried a new coil which changed nothing. 
      ANY help would be appreciated. Too much invested to not get it running right. 
    • By JacobSlabach
      got 7 atvs off CL recently for a good price.  one of which is a yamaha warrior.  anyone know where the vin is printed on this bike?  Haha good place to start as I do not know year or size yet.  The former owner says needs exhaust ans and clutch work.  he said it ran fine until the clutch cable broke and then I couldn't get the new cable adjusted right and it would grind gears.  things I see:  clutch cable locked up again, no brakes, carb leaking (green with algae around the bowl and has gelled gas stalagtights on it), aftermarket exhaust melted the airbox so I need something different and a new air box.  I would like the use the current exhaust if I can but I have a feeling its a redneck fix as it looks like there is an ace bandage holding it to the exhaust pipe (its an aftermarket slip-on exhaust), so I'm not sure about that- lets get the bike running first.  also, battery (looks brand new, what a shame) is dead, 0 volts.  Otherwise, bike looks to have not been wrecked, and plastics are ok (it sat outside under a 'tarp' for 3+ years since it was run last).  any tips and advise on where to start first would be awesome as this is my first clutched bike (manual).
      the clutch is my main concern- I've never rode a clutched bike so I dont even know what its supposed to feel like.  lol I'm spoiled on my automatic polaris 
    • By Squirrel
      So I bought a Bayou 220 as me 'Black Friday' score, and was informed it has carb issues.. 
      A little history from the previous owner: they suspected the carb was bad as it was 'running like crap' so they did a rebuid kit on it. Didn't fix issue so they took it to a shop where the tech installed an aftermarket(?) carb, but had to modify the throttle cable to get it to work. Quad ran great at 1/4 throttle, but anything above that and the throttle would stick and the machine would run like garbage again.
      What I know and think: I hear carb issues are common and fairly easy to fix. Also, I think they used the 'universal' rebuild kit that claims '88-'11, but the jets and such were different from '00-'03 (gaskets, etc. appear to be the same) so their original attempt was a good idea, just not good enough.
      They did give me the original carburetor with the 4-wheeler, but it has the wrong internals. I'm thinking if I can get the right jets, springs, etc for the rebuild, I should be able to get this thing running right. Of course, I still need to charge the battery back up, change all the fluids, replace fuel lines, plug and wire.. ya know, the basics for a machine that's been sitting for roughly 9 months. lol
    • By goldeneagle
      I have a 2000 warrior thats seems to run fine. But I am having a problem with the gas boiling in the tank. Does anyone else have this problem or can anyone give me suggestions on how to fix this issue? Thanks Bill.
    • By 79davecampbell
      just bought a 2000 polaris 325. was told i vould pull start and ride but needed new battery for electric start. so bought new bat and charged it but nothing. while spraying with a hose after a ride it all came on. neutral light cooling fan and then quit. checked those things in the black bag and power at both ends. starter will roll when i jump solenoid. power to the ignition switch jumped that but still nothing. maybe switch for headlight and starter? NEED HELP PLEASE. 
  • Similar Tagged Content

    • By johnwayne
      i have a 2000 suzuki king quad lt-f300f that i picked up as a project bike. it didnt run well when it was parked outside 5 years ago. it cranked after putting fresh gas - but would not run below half throttle, i took apart the carb, cleaned debris, and re-assembled. i suspect that the pilot needle is sheared off - it never protrudes into the throttle body through the pinhole. now to get the bike to ALMOST idle, the throttle idle adjustment knob is all the way up/in. the pilot needle is turned almost all the way in/up (if i understand correct, it should nominally be out 2 1/4 turns or so). and like i said, it will ALMOST idle. floods easily, rides rough.
      wanted to hear from those more experienced than me with suzukis - and im self-taught atv repair, so dont laugh too hard if my verbiage/part names is way off. 
      facing the driver's side of the bike [US] there are three hoses on this side of the carb. without a service manual or way of knowing what was messed up before i got it, i think i have them right: front hose as a vacuum to the petcock, middle hose as vacuum to the fuel pump, rear hose as fuel line from the fuel pump. running the bike in prime position results in flooding even while riding. with all hoses disconnected from the carb, fuel slowly drips from the vacuum line connected to the petcock.
      so just my speculation is that the diaphragm in the petcock is split, and the pilot needle is broke off - causing my inability to not quite idle and the rough ride. this suzuki is hoses and cables everywhere compared to the honda ranchers and yamaha warriors i am used to. I would like to have a plan rather than: replace everything at once.
      is my speculation on the right track, or could something else be at play? say, if the compression was non-existent, would that cause non-idling? i am all ears, look forward to the input.
    • By skymankila69
      I traded my dirt bike for a 2000 arctic cat 500 semi automatic. when i went to go pick it up the guy said it didn't get spark, so i thought it was going to be something simple like a coil. well it wasn't. first thing i did was take all the plastics off to get easy asses to every thing. so i bought a brand new battery for it seeing if it got power, it didn't. the dash wouldn't light up neither would the lights, so then i tried to see if the starter worked it didn't so i jumped the solenoid and the starter started turning over the motor. so i bought a new starter solenoid, when i installed it the electric start still wouldn't work , so i bought a new kill switch and starter switch that goes on the handle bars, when i installed it, the electric start still wouldn't work. so then i went to see if i could get spark by pull starting it, i didn't get any spark, so i bought a new spark plug, and guess what, still no spark, so then i bought a new coil for it to see if that would fix it. so i installed the new coil and guess what no spark still and still no power to the dash. so to sum it up i'm not getting any power any where to the four wheeler. so i cleaned all the leads and plugs and still nothing. so then yesterday i took the wiring apart to see if their was any frayed wires, and no their wasn't. does any one have any ideas what this could be i'm up for anything. also if any one knows how to bypass all the wiring just to get it to start i open to that to, or if someone knows where  i can get a wiring diagram.
    • By quinnkaeb
      i have recently purchased a yamaha kodiak ultramatic 400cc. it is used and sat outside for a long time. i have done a lot of work on it and got it to run sort of. when i try to start it, it will start and run for a little bit then it will die, the time it runs varies. it has a new cdi, spark plug, and stator. most of the time it wont even start it just cranks over. there was one time that it started up right away and ran perfectly but the next time i tryed it wouldnt start. before that one time every time it started and ran it had a popping sound. i cant figure out why it wont run. any help would be muchly appreciated! thanks!
    • By sloundez
      Does anyone out there know where I can get a functional pair of wheel cylinders for subject ATV? Any suggestions welcomed. Thanks
    • By marcuslachance
      I
      I bought a Honda 250sx 1986 but the exhaust is broken. Apparently it's not possible to order a new one. I checked to order one on others compagny but there's noting.
      Do you know which exhaust it's possible to install. Is there a company who sold an exaust to fit on my 250sx.
      Sorry for my english
      Thank you
      Marc
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...