XR400 Wont start !!!

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Posts: 3
Joined: Apr 17, 2018
Location: Brisbane
Rides: M109R, GSX750F, KLR650, XR400R, 6 x CX500 and 2 x RL250.

XR400 Wont start !!!

Post by Oldlonely » Mon Apr 23, 2018 6:44 pm

Hi all, I have recently purchased a 2003 XR400 in non running condition. Am desperately trying to get this bike to start and would love some advice please.
I do not have a shop manual yet and there must be something I am missing as the bike doesn't even look like firing !! :(
Firstly there was no spark and i found that the coil lead was loose where it joined the coil so I trimmed a tiny bit off and made sure the coil lead was screwed back into the coil properly. Now have spark but it is not a big fat blue spark and looks yellowish and weak. I checked the resistance of the coil lead with my multimeter before reassembly and think it was just over 5 ohms. Have ordered a new plug from the Honda dealer, but am assuming that this old plug should be enough to get the bike to fire. Have also stripped, cleaned and reassembled the carb. I have checked that fuel is getting thru by cracking the drain screw on the carb bowl to let some fuel flow out the lower drain hose. Also tried removing the plug and putting a small amount of fuel in the plug hole, but to no avail. Have also tried disconnecting the 2 x kill switch wires but that also didn't change anything, which, as I am running out of options, makes me think it might be an electrical or grounding issue.

Electrical stuff really isn't my strong point but I have found a wiring diagram on the forum for 1996 - 2004 XR400R. This wiring diagram shows the bike having 2 x grounding points, 1 at the ignition coil and one near the back of the bike.
I have the green wire grounding at the coil ok and have removed some paint on the frame to make sure it is metal to metal contact. I am concerned as my bike does not have the other green wire grounded anywhere near the back of the bike.
The wiring diagram shows it as being somewhere between the rear taillight and the A.C Regulator but it is not there at all
Could this be my problem or is the green wire grounding at the coil sufficient. ?
Any advice would be welcomed and appreciated. Thank you

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