49cc Huasheng misfires at speed.

Discussion in 'Motorized Bicycle Trouble Shooting' started by BikeSmith, Sep 6, 2016.

  1. BikeSmith

    BikeSmith New Member

    Joined:
    Nov 28, 2015
    Messages:
    15
    Likes Received:
    0
    For a couple of weeks now my 49cc Huasheng engine seems to be misfiring. at speed at a constant 1/2--2/3 throttle, and going downhill while still on the throttle, it sound like it is hitting a governor or something. it is fine while adding throttle. also a couple of times now after riding for lets say maybe 30-40 min. the engine has puttered out and just died. after about 5min it will start right back up and go. but will still have the misfire. I run strait 91 octain gas no ethanol. the only mod I have done is I built a 12in strait pipe out of electrical conduit pipe. I left the factory steel shim plate on between the pipe and head, could this be impeding air flow to the head fins? I did go to an iridium plug but it did not change anything. also put in 10-30royal purple oil after break in.scratgscratg could it be an electrical issue to the coil? Do these engine have a govenor? and if so can they be removed. already checked the fuel filters, and they seem to be good. Lastly I have noticed that after it does die, that there is some oil in the air filter. I would say I have had to clean the filter out bout every 6-7, 20min-1 1/2 hours rides.
     
  2. BikeSmith

    BikeSmith New Member

    Joined:
    Nov 28, 2015
    Messages:
    15
    Likes Received:
    0
    So after an extensive search over the workings of the bike. I have found nothing. Then today my friend comes over and the first thing he says is "why are there air bubbles in your fuel line?" Light bulb. the gas cap is NOT venting. after a quick blast of compressed air thru the cap vent. my bike once again runs great. sometimes it is the little things that we over look the most.:)dnut
     
  3. Tyler6357

    Tyler6357 Member

    Joined:
    Mar 15, 2012
    Messages:
    803
    Likes Received:
    10
    Sweet...I saw your post but had no idea what it could be.
     

Share This Page