/ Register

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

New engine not starting

Discussion in 'Yamaha 250cc In-Line 4's' started by stocky, Dec 18, 2011.

Page 2 of 2
  1. yyzmxs

    yyzmxs New Member

    Messages:
    0
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Nov 10, 2010
    It's either you valve clearance being completely out on some cylinders, or you have a massive air leak someplace. You will not get to the bottom of it, unless you do the valve clearance check first, in my opinion.
     
    yyzmxs, Jan 20, 2012
    #21
  2. stocky

    stocky New Member

    Messages:
    0
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Oct 9, 2011
    Looks like a couple of the ignition leads could be buggered. Any idea if these are easily replaceable, or leads off another model could be used?
     
    stocky, Jan 20, 2012
    #22
  3. dave

    dave Well-Known Member

    Messages:
    2,184
    Likes Received:
    26
    Trophy Points:
    503
    Joined:
    Apr 13, 2005
    Gender:
    Male
    Occupation:
    Instro tech
    Location:
    Tasmania
    My Bike:
    SV1000
    Just a note: When you pull one spark lead off you kill two cylinders. Make sure that you short out the end of the lead so that the other cylinder lead gets a spark.

    The electrical drawing shows the the spark Hi voltage winding is not grounded, so it relies on the spark jumping from one lead, though the plug to ground, back through the other spark plug to the other end of the spark coil.
     
    dave, Jan 21, 2012
    #23
  4. stocky

    stocky New Member

    Messages:
    0
    Likes Received:
    0
    Trophy Points:
    0
    Joined:
    Oct 9, 2011
    Well I'm making progress with it. I replaced the leads today, and gave the spark plugs a good clean. Seems to be running a lot better. I could get it to rev to 12k+ sitting still, so I think that's a good sign. However, after revving that high, it would drop back to around 7-8k and sit there for quite a while. Had to shut the bike off to get it to stop.

    It also seems to need to warm up a fair bit, even when its already warm, upon startup, before it wants to rev. If I start it and open the throttle, it wont rev, but if I give it a minute, it will rev fine. This also happens if say the bike stalls, and I start it immediately. The startup is a bit harder, and it still needs to wait a minute before it revs.
     
    stocky, Jan 21, 2012
    #24
Page 2 of 2

Share This Page