03 400ex start issue

[buckiguy]

Great forum, any suggestions welcome. All factory parts, no mods on mine (yawn I know :) Been hard to start last month or so. Would turn and fire, idle rough, if hit gas would stall, if didnt hit gas would often stall. Choke position didnt seem to make much difference. Then would seem like was flooded, could wait few mins and try again all the while getting better/warmer. Would finally get to start then ran great, no stalling at idle, etc. Ran other day for 1hr or so, temp outside was approx 30 deg. Went to start yesterday and turned, only fired once but rest of time only starter ran and seemed to have no spark. Replaced plug today and same thing so tested plug on side of block (I believe thats how to do it) and no spark whatsoever like I suspected. Any ideas on where to start? Any simple way to rule out bad kill switch? I have read all related posts and while helpful I didnt see a situation that was quite like mine. Thanks in advance. BTW, has gas, kill switch off provided its not broken, fuel on, choke on or off no difference, starter fluid made no difference.

[hondarider2006]

you said there twords the bottom of the post that the kill switch was off, doesn't that make it so it doesn't spark(I could be wrong) and also did you play with your fuel mixture screw? You may want to try going out on that, or going with a 42 piolet. Hope this helps a little;)

[cals400ex]

yes, i would first try messing with the fuel skrew. this is the bronze color skrew on the very bottom of the carb. it is hard to see and get too without turning the carb on its side. i would try to turn this skrew out 3 full turns from lightly seated. make sure you do a full 3 turns and not 1.5. if that doesn't work, you should probally just purchase a 40 or 42 pilot jet. that should fix your problem.

[buckiguy]

Thanks guys. I have the kill switch in the run position. I have tried the air/fuel screw in different positions. Shouldnt I still get a spark despite the air/fuel ratio if spark testing on side of block?

[BeltSlipper]

I had the same problem with my sons bike after getting the motor work done to it. But I think you mentioned yours is stock. Anyway, have you changed your plug? You might be running to cool of a plug. You should have a DPR9Z. If that doesn't fix it, try checking the fuse back by your battery. If thats good, you might want to test your Rectifier,Regualtor. Those often go bad. If that doesn't work,,,,,I'ld have to give it more thought.
Hope this works for ya.

[buckiguy]

Fuse is ok, plug is DPR8Z, brand new with correct gap checked.

[cals400ex]

dpr9z is a colder plug which could make it harder to start.

[BeltSlipper]

Cals400ex you are correct. I put in the wrong number. DPR8Z is the correct plug.

buckiguy do you know if you have a aftermarket CDI by chance? That will result in hard to start in the winter. I'm running out of Ideas for ya. This might be caused by it's 3am, and I'm old. But you might check to see if you battery is putting out the proper voltage. And last thought for the night (morning) is your plug boot tight on the coil wire? Those are my final thoughts I hope they helped. If not, you have to go to the professionals.

[Nausty]

yup, even if you get it to work go up on the pilot jet. 400ex's are cold blooded and both of ours don't start that well in the winter. Sometimes it takes what seems like forever to finally get it going and I gotta let it warm up forever.

[sickmojave]

mine was the same way till I went up to a #40 pilot jet. it would start then stall or would foul the plug. if I tried the choke I would have to change the plug. I went to the 40 now it starts right up and I haven't need the choke sence.;)

[buckiguy]

The cdi is factory, was reading manual and have it down to one of only a few locations based on the troubleshooting. I should be able to try them out in the next few days. What is a good site to obtain the 40 jet etc. or is it just an adjustment to the current carb?

[hondarider2006]

Originally posted by buckiguy
What is a good site to obtain the 40 jet etc.


C&D Racing;)

[ewalker302]

Quote

"Went to start yesterday and turned, only fired once but rest of time only starter ran and seemed to have no spark. Replaced plug today and same thing so tested plug on side of block (I believe thats how to do it) and no spark whatsoever like I suspected."





If you arent getting fire then no jets or anything else is gonna help.

I would check the plug wire connections at the plug & at the other end? for corrosion/tightness.

If they look good check the wire's continuity.

If the wire & connections are good ??

There is a main fuse also that may be blown.

Do you have a service manual?

:bandit:

[skemp]

To check the spark, hold it on a bolt or bare steel part grounded to the frame. This will at least tell you if it is getting spark, but you can't tell the intensity of it. Usually with these it is spark or no spark.

[buckiguy]

Service manual is on the way. No spark when I spark test. Fuses all ok. Per repair manual that I downloaded, it is either the cdi, faulty kill switch, or ignition coil. I will rule out the kill switch by bypassing it provided that it is that simple and go via the repair manual to test the other 2. I agree that the jetting wont make a difference since no spark currently. Does it make sense though that repeated tough starting has caused one of these others to fail?