Jump to content

2003 Honda 400ex starting issue


Recommended Posts

Hello! New to the forum and I have an issue with my project quad and I’d like to see if anyone here has any insight on how to narrow down the exact problem as I don’t have the money to just replace and test. I purchased the engine from someone and went ahead and replaced the top end with new pistons, rings, cylinder jug, and gaskets. It also has a hot cam so I don’t think the decompression valve is an issue. The quad turns over too slow (I think) to fire up which upon further inspection and research I discovered that the starter idler gear is supposed to free spin one way and not turn the other way, which it did not. So I took the stator cover off and messed with the starter clutch until it would freespin counter clockwise as it is supposed to, before it was acting like it was seized to the stator. After putting everything back together and turning it over I discovered that whenever the starter spins it locks back up again every time I fix it. Is this the one way clutch bearing, starter clutch, or something I am overlooking? Sorry for the long post I just feel like more info provided, the easier the diagnosis. Thanks for your time!

Link to comment
Share on other sites

The one way  bearing is actually a sprag clutch. . It  should  lock to  allow the  starter  to turn  over the motor in one  direction  and free wheel  in the other.  This is  so  when  you start the  motor the  revs of the  motor  do  not feed back through the  gearing  and spin the  starter  to  destruction.

The starter  should  lock the  sprag  to  turn the  motor  over.  If it doesn't the  stater will  just spin free and nothing else happen. From  your description  the sprag is working properly.

If  it  seizes when  the  motor  starts  it will  spin the  starter as I  mentioned..  When  the  motor  is running  the  sprag  clutch is disengaged.  The  outer  part  spins with the  motor. the inner part  is where the  special   rollers  are  that  lock  the  clutch  when the  starter is spinning the  motor  over.

Link to comment
Share on other sites

Thanks for the reply! Just so I know we are on the same page because I’m not sure if I explained it as well as I could have. I would crank it over for just a second and take the stator cover back off to find that the starter clutch would no longer freespin counterclockwise, it would have a lot of resistance and turn the stator (and the crank) with it the same as spinning it clockwise. I then hold the stator in place and turn the starter clutch and eventually it will freespin again counterclockwise and turn the crank going clockwise (as it should I believe.) I put the cover back on and repeat with the same results every time.  

Link to comment
Share on other sites

I can't if that is  normal  or  not. It  may  be wearing a bit  and binding but the  only way I know  of  it  to  actually  have it start the  motor. When the  motor  starts the sprag  should immediately  release as the   motor speed exceeds that  of the  starter  gear train.  It's very possible it  is worn enough  to  bind  a bit when the  motor  doesn't start but  that hurts nothing as long as it  instantly releases  on motor starting.   The  special "rollers " in the  sprag  are  actually  either  a figure  8   shape or  could be  a  sort of  half round  shape  so  in the  one direction turned by the starter  they  twist  a  bit in their  slots  and  bind the   inner  and outer  parts together . . When  the  outer  part ( connected to the motor) spins  faster than the  inner,  those  rollers  lay  down  and release the  bind   between them.

There  are   tutorials on  Youtube   that explain  how a sprag works  much better than  I  can

Link to comment
Share on other sites

The  working of that sprag  should have nothing  to  do with the  speed the starter  turns the motor  over  unless it  was actually  slipping  when  it  should be  bound  tight.  If the  motor  is  slow to  turn  over  on the starter  it is  more likely  either a low battery ,  starter dragging  or  possibly just  tight   rings  in  the  new cylinders .Are  the   piston  and  ring  clearances  on spec?..  It's   possible  for  some binding there   if they   are too tight  in the  bore.

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.

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 Spritee1
      having an issue with the unit when running under a load up a hill or in high gear, seems like the belt is slipping, there is a clapping sound coming from the primary clutch like it releases and snaps back in. i don't think I should have a noise like that. this is a friends unit and he has already replaced the primary twice with the same result.
      not sure where to look next
    • By semicolon
      Hi, I am having issues with my TRX350D fuel pump.  It suddenly stopped running so I have replaced all the fuses and cleaned all the terminals.  I have fitted a new pump, fuel cut-off relay and rectifier.  Still nothing!!  The pump runs when attached to a battery.  The engine will start on the choke and the filter fills with fuel but it will  not rev and dies when the choke is closed. I have power to the relay but nothing at the pump black/white wire when cranking the engine.  Any ideas where to go from here would be very much appreciated!!
    • By HSTAR
      Hey I have a 1997 big bear 350 4x4
      I replaced the shifter shaft and the shift arm linkage and the rod when I installed them all I was unaware that you had to line the dot on the shifter shaft with the gap on the linkage arm gap put it all back  together and rode it I can't get it to shift in the right gears  I can move the shift cam by hand and goes in different gears but with the shifter shaft in it riding I can't put it in R or N 
      Anyone know how to line up the shifter shaft and the shift cam s
    • By NZrider
      My king quad 700 runs rough when cold then won't start some times but not often when it's hot. And occasionally smoke's a lot when it's cold I'm guessing that's rings but I'm worried unless it's causing the other problems
      All help is appreciated thanks
    • By jatho
      Has anyone else had an issue on older king quads where the oil would leak from the top of the head (due to a failed gasket) and drip onto the hot exhaust? Mine got so hot one time it caught fire. Just wondering if this is a common issue, as I've seen the same thing happen on multiple bikes that were the same model. 
  • Create New...