Quantcast
Jump to content


big bear 400 miss fire when cold


gangle04

Recommended Posts

Dont kno if i would exactly call it a missfire but sometimes when i fist get on my quad( after letting it warm up with choke for five mins ) and rip away usually right after shifting it will miss 1 spark blow that air/fuel into exhaust and backfire then run normal sometimes itll do this 2-3 times aways in the beginning of a ride usually if i warm it up a little less then usual, just curious what would cause this. It did it since i got the quad 6 months ago and theres a different head cyl. And piston in it now...also what would cause oil to stop flowing into a head??? Or did i screw something up??? On the new head i noticed oil poors out behind cam sprocket on the old one it didnt

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 BruceG
      Hi guys. I have a problem where the quad will start and run well for about 5 minutes and then it dies. On inspection the airbox has oil in it (quite a lot). The oil is pumping through the cylinder head breather hose. This problem first happened suddenly. I have since done the top end including, piston, gaskets, rings and valves. I have also done the carb (not that I thought that this was the problem). The compression seems normal. The only thing that I can think of, is that I did not grind the valves well enough. Anyone experienced this? If so, how did you fix it? Any other thoughts?
    • 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 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 mehim
      Hi everyone. 
      Let me explain the thread title. 
      My husband and I are very active in the nudist community, and we have stayed at many and most of the mainstream nudist and clothing optional campgrounds in the USA. We are now approaching our retirement and would like to start a podcast to share those off the road / backwoods / little known camping areas where nudity is allowed. We have purchased a 5th wheel camping trailer with a rear garage for the ATV and now need some good reports on the one to buy. 
      We are most interested in a side by side unit but would love to get your thoughts. 
      Feel free to stop by and say Hi and ask anything you would like to better understand what we are looking for in an offroad unit. 
      Thanks for reading and hope to hear from you. 

    • By hardcastle
      My friends KQ 300 starts fine and runs, as soon as you put it in gear and try to accelerate its bucks and farts like crazy, not moving... I cleaned carb and it worked good for 1 day... now back to same problem.... could it be such as a bent valve????
×
×
  • Create New...