wr 400 help maybe timing or carb ??

6 replies to this topic
  • yellowsnow

Posted March 17, 2009 - 02:07 PM


ok i'm working on a 99 wr 400 for a freind . the bike sat long enough for the carb and petcock to be good and clogged, but the guy says it ran good when parked. well i cleaned the petcock, tank, all jets, float bowl, and put in a new float needle assymbly. the bike has good fire, good compression, the float bowl is filling with fuel. but will not try to fire, if i spray some starter flued in the back of the carb it will backfire once or twice but not try to run at all. so i'm remembering having the timing chain tensioner off to make it easier to remove the carb and forgot it was just put back on loose and kicked the bike over. but the marks seem to line up perfect. on the cams the middle of the 3 dots is up while the I from HI flywheel is to the line...unless i'm doing it wrong. do you go by the I on HI ????? or is their something else on the carb that needs to be cleaned before it'll do anything? thanks for any help...i'm kinda stuck on this one

  • yellowsnow

Posted March 17, 2009 - 03:07 PM


well now i'm figuring carb, or maybe stuck valve. if i have all the jets clean and fuel in the bowl it should start right? i only cleaned jets and stuff under the float bowl and didn't mess with anything else on the carb. but when i pull the spark plug its always dry. what else on this carb would make it not start at all?

  • William1

Posted March 17, 2009 - 03:38 PM


Replace the pilot jet, make sure the hot start closes and clean all the passage ways in the carb very carefully. Use only rubber safe solvents, no strong carb cleaners.

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  • maxtherat

Posted March 17, 2009 - 05:11 PM


Does the 400 Have a TPS? If so, I hope you only unplugged it and did not remove it from the carb itself. That will contibute to your problems but, as stated above, the PJ is the best place to start.

  • Usedup

Posted March 17, 2009 - 06:23 PM


If the carb. is not the issue, remove the valve cover, do the I thing with the timing mark, and then look at the lobes. They tell much more than the marks on the cams. I can testify! Somewhere on here is the trick of rolling back the intake cam by hand to take up the slack on the timing chain. Timing can be off enough w/o jumping a tooth that it will not start.

  • yellowsnow

Posted March 17, 2009 - 07:54 PM


thanks yes i only unplugged the tps. i'll mess with it some more tomarrow

  • matt4x4

Posted March 18, 2009 - 03:34 AM


TDC should be the mid point on the H mark - but verify this by removing the plug, sticking a long pencil in the hole - pencil at it's highest is TDC. At this point, the lobes should point towards the outsides (and just slightly up) and the outside dots on the gear should be LEVEL with the top of the head where the gasket would go.
Change plug to a new one - many times the plug can cause this.
If you have good compression you won't have a stuck valve.

If you've cleaned out the carb and are sure the pilot circuit is clean, then use the normal starting procedure for this bike which is:
Kick until TDC
Press decom lever, move kicker so you're just past TDC
Release decomp lever
Bring kicker to top
One good kick NO throttle at all and it should fire right up.

Have you checked your valve lash?
You'll probably have to clean out the AP circuit too the diaphraghm might be broken or clogged up, but this should not stop it from starting it'll just make it bog when you give it gas.
Also - when you had the carb out and apart - did you put the plate on the slide back in the right way - right way is Curved side UP - a common reassembly mistake.


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