Quantcast
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.

Thumpinhard25

01 bear tracker stutter/ bog, electrical ??

Recommended Posts

First thanks for any help guys, new to the forums and it's gotten me this far. I bought a 2001 bear tracker 250 for my family to get around the dirt bikes races. It wasn't running right and had a high idle. Previous owner thought it was a carb problem, so he ordered a new Zoom carb and new intake boot, but it still had the same high idle. ( I believe he had the throttle cable adjusted wrong, because it idled fine when I put it back together) So I tore down and cleaned the stock carb, and it started up and idled fine, but needed to have the choke 1/2 out to run.  I swapped to the new zoom carb and had the same issue. Choke half out bike ran ok. I played with the needle and the pilot screw with no change. ( bike did seem to be running rich though, but didn't get better when I tightened pilot screw or raised meddle) I Took it to the races and once I started bouncing around in the cattle fields the quad started cutting out real bad. It would barely run.  Sometimes it would run with choke off, sometimes choke 1/2, sometime choke full. I cleaned carb again, checked float level, and boots, no change still wouldn't run. Then suddenly it started running ok again.  This makes me believe it's an electrical issue rather then carb. I know there's no air leak, it's been checked, both carbs are clean( I've swapped them out a couple times, it starts up immediately and usually idles fine. But then bogs down/ or stutters under throttle. I saw the post on the guy who disconnected his rectifier and reconnected and suddenly it started working again, which lead me to believe it may be electrical and not carb.  So any advice on what I should check? Any way to test the CDI or rectifier?  Once again, I appreciate your help.  

Share this post


Link to post
Share on other sites


I would think the same, maybe you are losing spark under load? Does it start to bog down after its running for a while or pretty much random? Have you change the plug, checked your wiring? Maybe its a bad ignition coil?

Share this post


Link to post
Share on other sites

I'd  check  for loose or corroded  connectors  in the ignition circuits  first since it started  after bouncing  around .  Check the  voltage   from  rectifier  to  battery under  idle  and revved up. If  you  can  borrow  a compatible CDI  box,  you  could try  swapping it  out.  There  is the service manual  for the  1998 YMF250  in the  downloads section of the forum .  It will  have all  the  resistance readings  for  the  ignition  components should you  need to  check  the  stator,  pickup  coil and ignition coils. Most  likely  the  readings would all be the same  for  the  2001.  Very little  changes  from  year to  year for the  same  series  motors.

Check  components  cold  and  warmed up. Sometimes   they  break  down   when  hot   but are fine  cold.  One tool  that  isn't expensive    but is  often  overlooked  when  suspecting  spark  loss  under  load  is  an  inline  spark  checker to see  if   the  plug  is  firing  properly  under  load.

Here  is an example of the  spark  checker https://www.harborfreight.com/90-in-line-spark-checker-69023.html

  • Like 1

Share this post


Link to post
Share on other sites

Well it's random. Sometime it starts cold and it's fine. Still has a little hiccup when I crack the throttle from idle, even with choke 1/2 out.  When it started running real bad ( as in wouldn't pull itself) it did it cold and hot.  I tore carb down and cleaned and it still did it. 

Share this post


Link to post
Share on other sites
46 minutes ago, davefrombc said:

I'd  check  for loose or corroded  connectors  in the ignition circuits  first since it started  after bouncing  around .  Check the  voltage   from  rectifier  to  battery under  idle  and revved up. If  you  can  borrow  a compatible CDI  box,  you  could try  swapping it  out.  There  is the service manual  for the  1998 YMF250  in the  downloads section of the forum .  It will  have all  the  resistance readings  for  the  ignition  components should you  need to  check  the  stator,  pickup  coil and ignition coils. Most  likely  the  readings would all be the same  for  the  2001.  Very little  changes  from  year to  year for the  same  series  motors.

Check  components  cold  and  warmed up. Sometimes   they  break  down   when  hot   but are fine  cold.  One tool  that  isn't expensive    but is  often  overlooked  when  suspecting  spark  loss  under  load  is  an  inline  spark  checker to see  if   the  plug  is  firing  properly  under  load.

Here  is an example of the  spark  checker https://www.harborfreight.com/90-in-line-spark-checker-69023.html

Man this is great advice.  I'll pick up a spark tester on the way home. Now that I'm back at the shop ( and not in a field) I'll pull the plastic off and check all the connectors. I do believe I have a bare wire showing at one connector where the insulation has pulled back at the plastic.  I don't  think it's shorting but I'll double check.  The bouncing around and randomness of the sputtering is why I believe it's electrical as well. I was reading about some "parking break" governor or something. What exactly happens when the parking break is engaged? Is it possible to disengage it completely to ensure its not a faulty switch? Also I'll keep this thread up to date until I find the solution, for any future people to read.  

Share this post


Link to post
Share on other sites


Any chance the fuel tank has junk in it ? Maybe remove the petcock (gastank valve) and check the screen and inside to check for junk and that it’s not starving the carburetor for fuel? 

Esp since you said when you start moving the bike around it gets cranky.  

 

 

  • Like 1

Share this post


Link to post
Share on other sites

Sorry for the long update, since I posted this I blew the transmission out of my race bike, which ment tearing down the 450, while trying to rebuild my camper, and getting ready for a hard enduro competition on the one weekend that wasn't a race weekend. I have yet to mess with the bear tracker, however I did take it to the last event and it basically stopped running. Stumble is so bad it barely has power to pull itself, choke in, 1/2, out doesn't matter it wouldn't run.   So I'm hoping to get around to tearing it down in the next week or so, I will still update this page when I figure out what's up. 

  • Like 1

Share this post


Link to post
Share on other sites

Well I finally found some time and I'm back at it again.  I went back to the stock carb, ditching the zoom zoom it had on it. ( stock carb had a stripped out pilot jet) but that's been removed and entire rebuild kit had been done back to factory settings. I put it on and it ran fine, for about 10 mins. My wife then rode it around the yard and said it did fine. I got home, cranked it up and it started fine, idles great, but as soon as you get on the throttle it wants to die. Seems to be mid throttle.  Pulled all the plastic and don't see any shorts, disconnected the brake safety switch, no change. It already has a new intake boot, but sprayed around all the carbs and boots with starter fluid and no idle change. has a clean plug in it as well.  

Share this post


Link to post
Share on other sites

Have you had a chance to try  another stock  carb on it ?. It  still sounds like a  lean burn problem  off idle.I'd look again  for a clogged  passage or a  small  missed drilled  hole  in one of the jet tubes .  Make  sure  float  level  is right  and  no  crud is coming from the tank to possibly restrict fuel  flow ..  Is the diaphragm  good /new and working as it should?  Is the  spark  plug  new  or known  good ? Some plugs  can be fine at  idle  but  under the higher pressures  when  throttle  is opened can  cut out  or  be  intermittent . 

  • Like 1

Share this post


Link to post
Share on other sites
22 hours ago, davefrombc said:

Have you had a chance to try  another stock  carb on it ?. It  still sounds like a  lean burn problem  off idle.I'd look again  for a clogged  passage or a  small  missed drilled  hole  in one of the jet tubes .  Make  sure  float  level  is right  and  no  crud is coming from the tank to possibly restrict fuel  flow ..  Is the diaphragm  good /new and working as it should?  Is the  spark  plug  new  or known  good ? Some plugs  can be fine at  idle  but  under the higher pressures  when  throttle  is opened can  cut out  or  be  intermittent . 

I tried the zoom carb, and it wasn't right. Rebuilt stock carb was good " for a few mins". Im going to stick a new plug in it again. I tore the carb apart again yesterday, triple checked and all passages are clear. Float is set at 13mm. No fuel filter on tank right now, good flow from tank to carb. Throttle slide boot had no visible holes, or rips, same with the side rubber enrichment thing. what are the symptoms of a bad CDI?  

Share this post


Link to post
Share on other sites


I've  never  had  to deal  with a failing  CDI,  but it  is possible  for  one to  become weak and intermittent  as it  heats  up . You seem  to  have pretty much eliminated  everything else .  Hopefully  you  can  borrow  a good  one to  try  before  putting out  the bucks for a new  one .  Friends of mine who  had  CDI problems  had them  fail  completely  when they went.  Like  anything electronic though, a component  can  get  weak  or out of spec  and  cause problems.  

  • Like 1

Share this post


Link to post
Share on other sites

Great updates and advice in this topic! I’m enjoying following it. If it now runs better with the stock carb but on higher throttle bogs down, could it be jetted incorrectly?



Sent from my iPhone using Tapatalk

Share this post


Link to post
Share on other sites

So here's the challenge. I have 7 days to make this ( never ran right) ATV and get it running, so that I can't take it to Colorado on vacation next week.  I also have to work 6 of those days.... So got some work ahead of me.  My next step is to pull the stock carb, and rip all the jets out of it, swap them into the ( new) zoom carb.  If it still doesn't run right, I should know for sure that it's not a diaphragm issue, or carb issue and more then likely electrical. We will see what happens. 

Share this post


Link to post
Share on other sites

Update:   No solution was found... not the greatest outcome but I wanted to update this thread.  I sold the Bear tracker as it was.   I will try to update the original post to state that to save people looking for the same problem in the future time. 

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 jimybud
      Below is a quote from a response to similar question from yesterday: 
      "Easiest thing to check is trash in the main jet.  if it idles fine, then the idle circuit and low speed jet is clear.  if it bogs off idle that's when it's transitioning to the main jet." 
      I will go ahead and open up the carb and check the main jet, but please respond to this post as if the main jet is squeaky clean.
      Below is my post:
      Only starts and runs on Full chock. 
      Does not matter what position I have my "mixture" screw.   Tried it at zero, 1 turn, 2 turn, up to five turns.  Spent a few hours confirming that the position of the mixture screw does not resolve issue.
      Runs great at idle and if I slowly engage throttle, it will rev up as expected.  But, quick rev up or when I am trying to drive it, it spits and sputters and looses power.
      I also use a propane bottle and did not find any obvious leaks, and the vacuum port is hooked to fuel peacock and I also made sure to simply block the port with my finger to see if that would resolve the issue.
      New Carb (after market), New Coil, Fresh Gas.  No leaks at manifold boot, hot battery.  Good gas flow.    Runs too good to be a valve issue, or cylinder, great compression.
      I can move the choke out a tiny bit, and it will still run, but will still bog down when I try to power it up.
      I also have a 250 trail boss Polaris that I require to run at full choke, but it has power at all throttle potions.
      I suspect it is running rich as the choke is on, but will not run with it off.
      Any details would be appreciated.
    • By donerightautomotive84
      Ok so 2000 sportsman new.caltric carb new fuel pump new jug and piston new cdi and coil finally get to start it and itll idep for 5 to 10 seconds and die what am i missing people any help id love ya forever lol
      Sent from my LM-Q720 using Tapatalk
    • By dctaz37
      Hello, the ATV doesn't stop anymore so I guess it is time to replace the brakes. Looking for part number and instructions. I think it may have shoes front + back and the front would be hydraulic. 
    • By Hunter19
      How are you doing guys I just joined I have a 1998 Suzuki King quad I’m having problems with high RPMs the ATV idols perfectly but soon as a throttle up it doesn’t stall but it just bogs down it has no power any suggestions thanks
    • By Thehick344
      I have a 2001 650 quest that ran great. Shut it off, wont start. Got tinkering at a buddies, it ended up in a snowbank. Lost my train of thought since then.  I have a black, red, green  top with two plug in wires yellow and yellow and red I believe.. I have a new battery. Just dunno what to do. I tried hooking the wire coming up to the solenoid on the far side, then directly across I put the positive cable and it instantly started turning over without the button being pressed until I took the cable off.  The little black resistor box has also been eliminated.   Any help would be greatly appreciated.. 
  • Similar Tagged Content

    • By David Goff
      So i have an old yamaha bear tracker that was given to me from an old farmer I know. I decided to refurbished it and fix all the quick fixes on it. I am pretty sure that it is either a 1999 or 2000 based upon the original wiring harness. Little did i know when I bought a new to me wiring harness from ebay that it was from a 2003 or 2004. My question to everyone is do I need to have all the stop switch assemblies hooked up? I think there are three on the 03/04 models and only one on the 1999 to 2000. Any help I can get for this would be great. I haven't run it yet due to the motor and crankcase is in two totes. 


    • By Brent Mason
      IMG_4272.MOV Originally had my griz600 stop running and then wouldn’t start ! After testing all coils , valve lash , compression (115psi) and all tested ok I bought a used cdi . After cdi install it still wouldn’t start (no spark) ! So even though the stator , pulse/trigger and charge coils check within good range I decided to switch the stator etc ! It started but It is very unresponsive on throttle and acts like it is running in 2 Different spark timing ! With slight throttle it will take off good but instantly go into a very different running mode with no power like timing very retarded but it will switch back to running good for short period then bad again !  Since I replaced the stator and it started I then decided to install the cdi I replaced and it did the same thing ! Also I noticed the Used cdi I Took off had a capacitor that had swelled and extruded from the back of the cdi . I had always heard and I believed that when these CDIs go bad they machine will quit and will not run . Is that true ? I also checked the cam/valve timing and its ok ! Checked with timing light and it does fluctuate on idle ! I am thinking I have 2 bad CDIs . I also switched the trigger Coil wires and would not start then . Man , this thing ran good before and I am confused ! Video below may help !
      IMG_4272.MOV
    • By Brent Mason
      1998 Grizzly600 ! Slowly died then wouldn’t start ! All coils check good ohms ! Checked ac voltage from source coil get OL ! Is the source coil bad ? 
    • By Aj Hurtibise
      Hey guys I'm new to the Forum I just got a 2000 Honda trx90 looking to make it go a little bit quicker I don't know much about four wheelers but I am a technician at a dealership so I know my way around a motor.
    • By Arnold Schimberg
      Hi Guys
      I have 88 4trax FW , it has a booster circuit
      In the cdi control fed from a leg in the alternator. 
      MY Honda service manual says you will get no spark without this circuit on this model. 
      Can someone explain a little about this please ?    Thanks
  • Recently Browsing   0 members

    No registered users viewing this page.


×
×
  • Create New...