'00 WR400 Carb Question


14 replies to this topic
  • FasYankee

Posted August 17, 2009 - 06:46 PM

#1

Ok, just got a '00 WR400 that I'm planning on converting to sumo duty.

The bike has sat for at least 1.5-2yrs without ever starting.

I ran fresh gas through it, with some carb/injector cleaner. (the old gas wasn't even flammable anymore.:thumbsup: )

Here's the symptoms, hoping someone could point me in the right direction before I start off like a blind rat in a maze:

Cold: Bike will not start with choke out, only with choke in. Then bike will not stay running unless choke is pulled out.

Hot: Bike will not start with choke out, same as above, but occasionally pulling the hot-start out will aid in quicker re-starting.

So basically the bike will start but then needs the choke to stay running even when the bike is warmed up.

The bike is bone stock, with the exception that the cap on the end of the stock muffler has been removed. (guy must have thought it was ohh so "cool" to be able to make that noise:bonk: )

Is there a baseline that I should be working from as far as needle height/jet selection?

I know that I need to take the entire carb apart and thoroughly clean everything. I'm worried that this guy got advise to "get a jet kit" since he removed the silencer plug, and muddled everything up, especially since there's notes in the jetting section of the service manual....all chicken scratch mumbo jumbo.....

I plan on doing the throttle stop/grey wire mods eventually, but would like it to be reliably starting first, and then work from there.

  • pablo83

Posted August 19, 2009 - 01:24 PM

#2

I know that I need to take the entire carb apart and thoroughly clean everything.


Exactly. Who knows, he may have jetting the thing properly. No matter how it's jetted it shouldn't be acting like you describe, so clean the thing up real good first. Make sure the AP is working well too. If not, check out the O-ring mod.

One question: are you giving it gas when you try to start it? If so, don't.

  • tribalbc

Posted August 19, 2009 - 03:18 PM

#3

Replacing the pilot jet, as your syptoms point to a clogged one, would probably fix things up.

And as you said a carb cleaning will be good as well.

As far as baseline jetting I have no idea on the older models.

  • FasYankee

Posted August 23, 2009 - 08:07 PM

#4

well, here's an update, and the list of things that were fubare'd

A: on the slide of the keihn fcr's there's a black plate...that was installed upside down, effectively cutting off the air supply at closed throttle.

B: the needle clip was exactly opposite as to where it needed to be.....remember ya'all raise the clip to LOWER the needle and vice versa.

C: the float bowl vent tube (1/8" dia brass tube to snorkel air into bowl) was snapped off and had some sort of JB weld holding it on.....explains the leaky vent hose...

D: the 175S jet was "drilled" out.....really, some people should just keep their hands off......

That was it, items replaced, repaired and re-set..and the thing starts 1st/2nd kick every time, runs mint too. Has a slight hesitation if the throttle is yanked to it's stop from low down, but it's negligable.

Apparently this guy bought this bike, let a friend "borrow" it for a trip, and it never ran right when he got it back, so he hardly rode it. His loss, someone elses stupidity, and my elbow grease becomes my gain!

bike will be 'tarded soon!

  • pablo83

Posted August 24, 2009 - 11:46 AM

#5

well, here's an update, and the list of things that were fubare'd

A: on the slide of the keihn fcr's there's a black plate...that was installed upside down, effectively cutting off the air supply at closed throttle.

B: the needle clip was exactly opposite as to where it needed to be.....remember ya'all raise the clip to LOWER the needle and vice versa.

C: the float bowl vent tube (1/8" dia brass tube to snorkel air into bowl) was snapped off and had some sort of JB weld holding it on.....explains the leaky vent hose...

D: the 175S jet was "drilled" out.....really, some people should just keep their hands off......

That was it, items replaced, repaired and re-set..and the thing starts 1st/2nd kick every time, runs mint too. Has a slight hesitation if the throttle is yanked to it's stop from low down, but it's negligable.

Apparently this guy bought this bike, let a friend "borrow" it for a trip, and it never ran right when he got it back, so he hardly rode it. His loss, someone elses stupidity, and my elbow grease becomes my gain!

bike will be 'tarded soon!


Good job. :ride: I had that same "upside down" plate issue. It can be difficult to find if you don't know about it.

Try to O-ring mod to get rid of the low end hesitation. It's super cheap and easy and often has an amazing result.

  • FasYankee

Posted August 27, 2009 - 05:27 AM

#6

Well, another update, everything was running fine, went and did the grey wire mod.....now it's got a wicked hesitation down low. Going to lower the needle clip and see how that fares.....if not, maybe have to fatten up the pilot jet I guess....we'll see.....

They should have designed an easier way to get the damn carb out......taking the subframe 1/2 off is such a PIA!

  • pablo83

Posted August 27, 2009 - 07:08 AM

#7

Well, another update, everything was running fine, went and did the grey wire mod.....now it's got a wicked hesitation down low. Going to lower the needle clip and see how that fares.....if not, maybe have to fatten up the pilot jet I guess....we'll see.....

They should have designed an easier way to get the damn carb out......taking the subframe 1/2 off is such a PIA!


Make sure your AP is working and do the O-ring mod.

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  • FasYankee

Posted August 27, 2009 - 08:43 AM

#8

Make sure your AP is working and do the O-ring mod.



AP is functioning properly.....eh...what's the O-ring mod? did a search and came up with too many results to read through....

  • pablo83

Posted August 27, 2009 - 10:14 AM

#9

http://www.thumperta...ad.php?t=651977

There's a better how-to somewhere in the CRF section, but I couldn't find it. This shouild be added to the FAQ sticky post

  • mrlopez

Posted August 27, 2009 - 01:05 PM

#10

Wow lots of info since I have the same problem basaclly on the same exact bike, plus some electrical issues. And mine it's Been convert it to Supermoto :-D

  • FasYankee

Posted August 28, 2009 - 06:01 AM

#11

http://www.thumperta...ad.php?t=651977

There's a better how-to somewhere in the CRF section, but I couldn't find it. This shouild be added to the FAQ sticky post



sweet man, thanks!:ride:

I'm assuming that makes the ap return on the cam immediately, kind of like a desmo, eh?

  • pablo83

Posted August 28, 2009 - 03:43 PM

#12

sweet man, thanks!:ride:

I'm assuming that makes the ap return on the cam immediately, kind of like a desmo, eh?


Exactly. For some reason the AP spring one most FCR's is weak and doesn't keep the two in contact or even allow the AP to run through a fill squirt. Merge Racing makes a stronger spring for $15 which is great, but the O-ring mod is cheaper and easier.

  • William1

Posted August 30, 2009 - 05:16 AM

#13

After the oring mod (or better the Merge AP spring), you may also want to try a smaller leak jet, like a 40~55. Then check the AP squirt timing, you want it to just barely miss the slide, to adjust, turn the screw on the AP cam. Tun no more than 1/2 turn at a time, test by riding and not just reving in the garage.

  • pablo83

Posted August 30, 2009 - 03:59 PM

#14

After the oring mod you may also want to try a smaller leak jet.


These bikes didn't get leak jets until '03.

  • William1

Posted August 30, 2009 - 05:25 PM

#15

LOL, did not notice the year.... my bad, sorry.




 
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