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Thread: Need some help on timing my 400ex

  1. #1
    Join Date
    Apr 2006
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    JeRsEy
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    12

    Angry Need some help on timing my 400ex

    I have a 1999 400ex i went out last month and bought a 440 kit for it and me and my buddy started to take the motor apart (the top end). After we got done taking the motor apart i got invited to go on a riding trip down in florida, but the problem was that i needed to send out my sleeve to be bored for the 440 kit and that was going to take about a month do to the fact that they were sending it to los angeles.I decided to hold of on that so i could ride in florida. Im down here now and im in the process on putting the bike back together and i got to the part with the cam, I need some tips on how to set the timing, i saw that on the cam sprocket there is 2 lines on each side of each other and i was reading that on a 300ex you just line them up with the sides of the top of the motor. Is this true? Is this it? i want to find out exactly what to do so i dont f$ck anything up or hafto take it all apart again, so if any one has any pointers please let me know ASAP, Thanks....Larry....

  2. #2
    Join Date
    Jul 2003
    Location
    Milwaukie, OR
    Posts
    167
    As long as you didn't let the cam chain go loose, your timing is fine, you just put the cam in how it would be at top dead center (assuming you took the thing apart the way the manual says) and make sure the lines are in line with the top of the head. Hotcams used to have instructions on their website. Also, make sure to use lock-tite on the screws that hold the cam to the sprocket.

  3. #3
    Join Date
    Apr 2006
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    JeRsEy
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    12
    Thanks for the info, What exactly do you mean by letting the cam chain go loose? the cam is in now and the chain is really tight so basically make sure the lines are lined up?
    99' 440ex,
    dg nerfs.
    dmc alien exhaust.
    race cut fenders.
    blingstar front bumper
    razr tiresdougles rims
    pro taper bars
    k&n powerpack
    gripper seat
    FUTURE MODS>>
    ELKA suspension
    ROLL DESIGN A_ARMS
    ROLL DESIGN STEERING STEM & STABILIZER

  4. #4
    Join Date
    Jul 2003
    Location
    Milwaukie, OR
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    What I meant was, that when you take the cam out originally, you are supposed to keep tension on the chain. This keeps the chain from falling off the sprocket that is in the bottom end. If the chain is loose, the crank could turn and the chain would be off a tooth or two. This would either advance or retard the timing.

  5. #5
    Join Date
    Apr 2006
    Location
    JeRsEy
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    12
    Thanks, i put eveything together last night and tried to fire her up. It was crankin but didnt fire.Seems like its not getting any fuel.
    99' 440ex,
    dg nerfs.
    dmc alien exhaust.
    race cut fenders.
    blingstar front bumper
    razr tiresdougles rims
    pro taper bars
    k&n powerpack
    gripper seat
    FUTURE MODS>>
    ELKA suspension
    ROLL DESIGN A_ARMS
    ROLL DESIGN STEERING STEM & STABILIZER

  6. #6
    Join Date
    Jul 2003
    Location
    Milwaukie, OR
    Posts
    167
    Are you sure that you put the cam in with the lobes facing the right way? Usually they are down when you take the valve cover off, and that is how they should go back in. Other wise look for simple things. Is the fuel on? If the carb's float bowl was drained when you took the carb off, you may have to pump the throttle a while until it gets full. You can also take the carb off and pump the throttle. You should see fuel squirt out of the accelerator pump. If this is happening, then something is wrong in the engine. Also check to see if you are getting spark.

  7. #7
    Join Date
    Nov 2005
    Location
    Chandler, AZ
    Posts
    4,021
    Lobes up or down doesn't really matter. It's just that if you install the cam with the lobes facing up then after the cam is installed you'll need to rotate the crank 360 degrees to get the engine at TDC on the compression stroke before you can adjust the valves.

    When the piston is at TDC and you install with the lobes facing up your engine is now at TDC on the exhaust stroke. Install with the lobes facing down and the engine is now at TDC on the compression stroke. No reason to install with the lobes facing up but if you do then just rotate the crank 360 degrees and it's just like you installed with the lobes facing down--no need to reinstall the cam or anything.

  8. #8
    Join Date
    Apr 2006
    Location
    Upstate NY
    Posts
    197
    Heres what I wrote in the other thread but in this case you can use the timing marks because im assuming you dont have the sparks timing key.

    Turn the piston to as high as it can get in the bore(TDC)by uscrewing the center plug in the case cover and turning that 17mm bolt till you get it right.put the head on and be careful not to get the timing chain snagged down in the base.After bolting down the head put on the cam.The timing chain sprocket should have 3 marks.The middle points up,the other 2 line up with the top of the head when you look at it from the side.Make sure the cam lobes are facing down.Now continue to install the valve cover etc.Hope this helped.
    2002 400EX
    Wiseco 11:1 Comp Piston
    Cometic Gaskets
    Dynojet Kit
    DG Exhaust
    K&N Filter w/ Outerwears
    UNI Air Vents
    JT Racing 15-38 sprockets
    O-Ring Chain
    Moose Rear Wheel Bearings
    22" Rears

  9. #9
    Join Date
    Apr 2006
    Location
    JeRsEy
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    The lobes are facing down. tonight i tried again and i replaced the plug because when it tries to start it sounded like it wasnt getting any spark but then again it doesnt seem like its getting gas either. the bike shoulda been flouded with the amount of throttle i was giving it, but yet it didnt smell like gas and when your bike gets flouded it stinks like gas. I dont know if a jet is clogged or what, all i know is i spent so much time and money into the bike im gettin so pissed off so any more pointers i would appreciate it. thanks....
    99' 440ex,
    dg nerfs.
    dmc alien exhaust.
    race cut fenders.
    blingstar front bumper
    razr tiresdougles rims
    pro taper bars
    k&n powerpack
    gripper seat
    FUTURE MODS>>
    ELKA suspension
    ROLL DESIGN A_ARMS
    ROLL DESIGN STEERING STEM & STABILIZER

  10. #10
    Join Date
    Apr 2006
    Location
    northern va.
    Posts
    8

    lil help

    if you dont know if you are getting spark you can remove your plug and hook it back up to your coil (the lil rubber piece or cap) and let it rest against your block so its grounded and turn your motor over and watch for spark this will let you know if you have fire!

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