Quantcast
Jump to content


1989 Moto 4 250 not starting.


Andy7734

Recommended Posts

Picked up a 89 moto 4 250 for cheap a few years back from a friend that was moving.   It ran and drove then, but wouldn't idle without quitting.  Anyway, I pulled it out recently after it has been sitting to see if it would start with a new battery.  It cranks but won't run.  Fuel is getting to the carb from the fuel tank and I have good spark.  If I pull the plug and pour a little gas in and replace the plug, it will run for a few seconds and quit.  I figured it has to be carb related so I pulled the carb and have been inspecting it.  There is some gunk in the bowl.  The big jet looks ok, but I think the small one is completely clogged.  I am guessing this would be enough for it not to start, correct?  Am I on the right track?  I like to dig into this kind of stuff but don't have much experience with small motors.  Any suggestions would be appreciated.   I did order a carb rebuild kit on ebay with new seals and rings for putting it back together too.

Link to comment
Share on other sites

THe small  jets  being plugged are  most likely the reason it's not running at all. The big jet is the main  one for  large throttle openings . The smaller jets and holes are for idling and part throttle.. You  can  use   welders   torch tip cleaners to  poke out the clogged  jets.  Blow the passages out  with "canned air" like they  use for  dusting out computers .

 

Link to comment
Share on other sites

Yes definitely  clean the tank too.

Get all the old gas and  any sludge that settled out of it  out .. I  have an  ol tiller that  gas was never drained out of  and it sat for years . There was still liquid in the carb  but a sticky  goo had settled out of it ..  The  seat  for the float pin was plastic and  swollen up as well as jets and passages were plugged .. I ended up  replacing the  carb.   I had to  completely fluch the fuel tank because it also  had that sludge in it .

Link to comment
Share on other sites

I  searched and like you didn't find a great video or instructions for adjusting your  carb , but this exploded view parts list will help you identifying the parts. The idle adjustment looks to  be the screw by the fuel  inlet.   The coughing , backfiring and uneven running is most likely caused by running lean. It is either a setting  out of adjustment or there is still a partial  plug  somewhere..

I hope this  helps.

https://www.partzilla.com/catalog/yamaha/atv/1989/moto-4-yfm250w/carburetor

Link to comment
Share on other sites

  • 3 weeks later...

Quick update.  I got it running much better but it is idling high.  The idle screw doesn't seem to have any effect.   I checked for an air leak and can't find any.  Could it be the something with the throttle?  Maybe the slide is getting all the way to the bottom?  Any ideas would be appreciated.

Link to comment
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 Forum Topics

    • By Mhatayas
      My uncle bought a Baja 250, 2006. Knew there was no spark since the get go. He don't know anything about quads so is getting me to help him try to get it running...
       
      battery is bad so I connected battery charger to it to crank it over , cranks over well , but no spark .... 
      Lights and everything work fine , but with each crank over using the e start switch , the display reads 999 888 777 666 ... Right down to 000 and repeats itself . 
       
      He managed to get a parts bike , I changed over the CDI and the coil and the stator from the parts bike and there was another black box by the voltage regulator I changed over ... I used my multimeter to confirm as much as I could works , it's hard without knowing which wires are which , and I cannot find any diagrams online for this bike ? 
       
      Do you think it could be the Killswitch? There's so many wires coming from there I don't know where to start . Also I should mention it appears the fan on the front of the bike has been taken off (the wires have been cut too ) 
       
      If this bike sparked it would run . The previous owner said he parked it one day and it just wouldn't start after.
    • By Mhatayas
      What should I do about this , bad oil leak where the filter cover bolts on . Can I use some gasket maker 

    • By Uglyside38
      I have a 1988 Quadrunner 250 2wd. My brother in law sold it to my son for $20...had been sitting outside for several years. Got it home and had it running in about 30 mins. Ran it a bit and then went to looking at the carb as it was having trouble idling. Was getting it pretty close, then started losing spark...Also, it wouldn't start up every time...only about 1 in 5 tries. Anyway...now, it has what I can only describe as "intermittent" spark. I can get 1 light spark right when the start button is pressed and sometimes one when it's released...but none while cranking. 🤷‍♂️

      I have replaced the spark plug, ignition coil/wire, and traced wires best I can. I noticed a couple frayed wires at the pickup coil where it enters the case. So, now I have the cover off, stator and pickup coil out and trying to test the coil. I do have about 114 ohms resistance for pickup best I can tell. And I can read minute voltage when I drag a magnet across it. Could it still be bad? Can a bad ignition switch/button cause this? (I did have the switch off to oil the choke cable)...pulling rope makes no difference though...any ideas or help would be greatly appreciated!!! It's the intermittent part that's throwing me off! 

    • By N00bie
      From Arkansas. Just bought a 2012 Gator 850i RSX because I could not pass up the price. BUT it has an idle problem. So, to be honest, I joined just to get a service manual. I have a choice: 1)Buy a hard copy: ~$100; 2)Buy a CD ~$35.00; Get a direct download for free posting 10 times; or get a download for $29.00 (subscription). Haven't decided what to do yet.
    • By Louznmemind
      Howdy y'all, I'm trying to fix a neighbors 2015 Brute Force 300. Came in with hard to start and won't idle except on choke issue. I pulled the carb and found the pilot jet as well as the emulsion tube partially clogged. Cleaned up everything, put it back together, still having issues...  It will start right up on choke and will also start off choke if you give it just a touch of throttle but it absolutely will not idle unless it's choked just a touch. Also, excuse my ignorance but I'm assuming the "dial" thingy attached to the carb that turns in and out is for setting idle?? 
×
×
  • Create New...