Jump to content

  • Do you own an ATV? Join our Forum!

    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.


2003 Suzuki LTZ 400 compression problem

Recommended Posts

hey i got a ltz 400 and we just took it apart and we looked at the piston and everything it was all good and the rings were a little dirty so we cleaned them and put them back together but there was some marks on the piston where valves hit it. could a bent valve mess up ur compression ?

Edited by DirtDemon

Share this post

Link to post
Share on other sites

Yes, definately, it your vavles aren't seating properly, compression will pass by. One way to check your head and vavles for leaks, is to pour water into the intake and exhuast ports and see if the liquid leaks past the vavles, and how quickly if it does. If your vavles are adjusted too tight, it will cause the same problem. However, even if you are losing compression past the valve, the piston/rings or cylinder bore could also be contributing to the low compression. Just because the piston and rings look ok, doesn't mean that they are. You should measure the cylinder bore with a micrometer to check for wear and to make sure it is still round. The piston itself should be measured for the same things. IMO, even if the piston and cylinder don't show excessive wear, the rings should be replaced anyway if the motor is more than a few years old. Also if your vavle have hit the piston, the structural integrity of the piston could be comprimised and should probably just be replaced. If it breaks while the motor is running, the damage could be pretty bad.

We will always be happy to try and answer any questions you have, but I still strongly believe that you should have a service manual at your side when you do this type of work to the motor. I may just be beating a dead horse here, but I think you would find alot of helpful info in there. Either way, good luck, and I hope you can get your quad up and running soon. I know how much it sucks to have a machine out of commission. BTW, I edited your post, please try not to use inappropriate language in the general forums. I know alot of other sites don't have much in the way of language rules, but we try to keep this one as PG as possible. There is a forum here dedicated to more "adult" themed discussion, you can basically say what you want in there. I have also merged your "compression problem" thread into this one, please try to keep things consolidated into one thread unless the subject matter is completely different. Not only does this help cut down on clutter in the forum, but you will get better input, if everyone can see all of the responses to the same question in one thread as opposed to posting the same question in two or more threads. Once again, good luch getting your quad fixed.

Edited by DirtDemon

Share this post

Link to post
Share on other sites

Messed up when merging your threads, accidentally moved everything into the timing chain thread. I only meant to merge the two that both pertained to your compression/vavle problem. Made this new thread and left your timing chain thread by itself, since it is of a different subject matter. Sorry for the confusion.

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.

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 Michael Rogers
      Ok, another newbie post here. Checking this stuff out in issues with lost compression. Wondering if anyone can tell by the pics and video of the cam is good, and whether you can see anything visibly with the valves and timing gear.
      Any input would be a great help. Been researching  youtube videos, but just not sure.
      2000 Bayou 220
      I could test the exhaust, it looked like it was opening, closing and seating ok, but not sure about the intake.

      CAM - looks like some wear on the outer ridges on both in spots, and one lobe to me looks kind of weird, but I don't know.

    • By Rich1028
      Good/Better/Best +1 A-Arms honda 400 X 2008-2014 
      What are some of the good, better,and the best 1+ a arms out there?
      where does Houser Racing Fall?
      JD Performance
      and something found on ebay
    • By BuckBilly
      Good morning to all !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
      Let's see if we can make this a daily event.
    • By Eric Harris
      How do you set the timing and adjust the valves on a 2006 sawtooth 
  • Similar Tagged Content

    • By Chayse Hill
      I have a 2003 LTZ 400 that i bought a few days ago. The quad was running fine until last night. I let my brother ride it down the street and back and i didnt notice anything etong with bike. Then my neighbors friend came over and said "can i ride it?" I said "sure" so he ripped it down the road all fine and when he got back it died right in front of us. My brother said it was dieing on him also. He also said that he wasnt using the clutch to shift. I told him he was an idiot. Im throwing that in there incase that caused a problem as well. But today i go to check it to make sure its getting fuel which it is and replaced the spark plug incase it wasnt getting spark but it is. So i started it and it was having a problem starting then i got started and was reving at idle high. So i took it around the block and it died on me a little bit down, so i try to restart it and it started so i kicked it into 1st and it kinda launched on me and started going with the clutch all the way in. Then it died right after and wasnt running right during that process and was idleing all over the place and just died and now i cant get it started it again. Before it would start without the choke or priming it. It would start real quick now i cant figure if it needs to be rejetted or something else. Air filter looks clean also. But any help would be gratelly appreciated!
    • By Jers
      I need to know what I have and what tire really go on it, Mine has 24x11x10 on the back and 22x8x10 on the front and I need new tire but I don't think are the right size. Also I can't find the model number listed but it looks like a 250 quadrunner 2wd and I think it is a 1987 maybe, can anyone help me, also I it has a rich running sound and I put a carb diap in it and cleaned the carb. is there a jet needing replaced?
    • By ut1w7b
      I have a 94 sportsman 400. It sat for several years before i got it. I have cleaned the carb it will start and run for about 5 min then it will flood. I have torn it down and cant see anything wrong. has anyone else ran into this problem any hel would be great.
    • By davidwestfall
      looking for direct shift shifting lever that properly fits my 2003 Yamaha warrior 350 and fits my foot the same as a stock 2003 Yamaha warrior 350 shifting lever fits my foot
    • By Wonderwoman
      Hello, well back to where I was last year with this carb. Took my 250 to the mountains for the first time this year and blue smoke, too much gas again. I can't believe that this carb gives me this much trouble. Seems like the choke is stuck but the cable moves freely. Anyone else ever experience this issue? Do you think a new choke cable would maybe resolve this?http://www.quadcrazy.com/atvforum/images/smilies/arghh.gif
      OK it was the choke. Put on all new cable and plunger and she is running 100% again. So now the question is, is the carb getting worn out where the plunger needle goes in the small hole and when I use the choke the needle end doesn't get lined back up with the hole?? We'll see how it runs and now that I know what the issue is I can always pull the choke plunger out and reinstall if I start having this issue again.
  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...