wr400 HELP!1


23 replies to this topic
  • wr400mutt

Posted March 14, 2013 - 05:04 AM

#1

OKAY SO I HAVE BEEN READING FORUMS FOR OVER A WEEK
and i cannot find anything that helps with the problem i having so anyhelp is greatly appreciated,
i have a 99 wr400, on a 03 trx400ex frame, and it is extremely hard to kickstart, i know how to do the
top dead centre trick,

i got this bike about a week n a half ago and it wouldnt idle i took carb apart cleaned it, with no luck,
then i did it again two days ago did a thorough cleaning of everything! got the bike to run with air/fuel screw at 1.5 turns
it kick start easily then, cut off wouldnt start back, if i jump start it itll run great! and then last night wouldnt start and then i pulled
HOT START not CHOKE and it started idled for a second and cut off! PLEASE HELP have a big ride saturday would like to go!

  • wr400mutt

Posted March 14, 2013 - 05:41 AM

#2

anybody have any ideas?

  • Krannie McKranface

Posted March 14, 2013 - 05:48 AM

#3

Your symptoms are those of worn intake valves: starts very hard with kick, starts easy with push/tow start.

  • wr400mutt

Posted March 14, 2013 - 05:50 AM

#4

okay so even though it started right up after i cleaned carb and would idle but i couldnt give it any gas without it cutting off, im extremely sorry computer messed up that wasnt in my original post, you still think its valves?
ive had those checked already for clearance

  • wr400mutt

Posted March 14, 2013 - 06:15 AM

#5

i just jump started it and when you get on it theres kind of a hesitation like it doesnt want to give it all of the fuel

  • Do I Care?

Posted March 14, 2013 - 11:41 PM

#6

I am having this same trouble as we speak. I am fixing a mates bike that is a WR 1999 400 with the Keihein Flat CR carb. First of all my starter jet was blocked (the little jet inside the carb sticking out),so I used a small pair of pliers & a strand of wire from an old throttle cable & used it to clean out the starter jet. I thought,maybe my problems would end there but NO...
I still have a problem with the fuel not getting into the diaphragm bowl (located on the side of fuel bowl). I'm still not sure why but I guess the little valve inside there needs replacing. If I stick a needle in the diaphragm inlet (located inside the fuel bowl),fuel goes into the diaphragm bowl. I tested it by filling the fuel bowl up with fuel with it removed from the carb,then using the little diaphragm rod (starter rod),I pushed down on the diaphragm. When I pushed a pin into the diaphragm inlet (located inside the fuel bowl) fuel shot up through the little hole on the side of the fuel bowl like it should. But,without the pin in there no fuel comes out at all because it cannot get into the diaphragm bowl.

This carb is VERY annoying to work on & seems to have a lot of troubles with this so I am looking into using a YZ carb or the WR 2000 model carb.

  • Do I Care?

Posted March 15, 2013 - 01:30 AM

#7

Just a quick update....
I kept poking the diaphragm inlet (hole in the bottom of the float bowl) & seem to have had a win with this method :banana:
Also the float needle seat needed a new oring. Not sure whether I want to buy new float/float needle for this one but maybe it's worth it??
Still looking into the Yz carb though & should be here soon.

  • MANIAC998

Posted March 15, 2013 - 02:52 AM

#8

Mutt, It's extremely difficult for us to diagnose your bike with the limited symptoms you've given us. Your going to need to figure out if your valves are tight, that's where I would start, and from there go in a systematic approach slowly eliminating one thing at a time. You say it runs fine whenever you get it running, so that kind of eliminates ignition issues and leads me to believe it is a fuel issue, of course this is just a guess, but that's where it's leading me. Those accelerator pump circuits are a pain to get clean and if they are plugged up, will certainly cause some of your issues!

  • Do I Care?

Posted March 15, 2013 - 04:24 AM

#9

I read your post ''better'' and realized that you don't have the 1999 FlatCR carb by how you described the last bit Ie.....
wouldnt start and then i pulled
HOT START not CHOKE

The FlatCR carb only has a choke. That said it would still be good to check the starter jet squirts fuel out in a nice stream. Rubber grease is AWESOME stuff for lubricating old diaphragm seals ,it turns a hard seal soft. If the diaphragm has splits in it though it will need replacing.
Maybe the starer jet/accelerator pump is squirting though & I wrote all this for nothing lol. Might help someone in future though if not now?

  • miweber929

Posted March 15, 2013 - 04:36 AM

#10

I'll echo Maniac's statements about a lack of info, and just add another set of questions to the mix and ask if you've ever gotten it to start correctly (as its a WR motor in a quad frame if I'm reading it right) and its just now acting up? Did you do the swap? If not did the PO switch over everything WR and do it right or was it cobbled? Was the PO able to start it without issue?

Reason I ask this if you don't have a baseline to start with, you are grasping at anything and need to start with motor health (valves, rings, timing, etc) before doing much else. This could be fuel, motor, electrical, really anything even down to your starting routine. I've been kick starting bikes since I was 4 (36 years now) and never had an issue with BSA's, Triumphs, old XR's, XL's, SP600, 2 strokes, whatever but I looked at a 99 YZ400 several years back and at 6'3", 235 lbs I could not get that thing to fire. The PO was a 5'7" 160lb soaking wet guy and could get it first kick; these things have a certain routine (not just the typical 1/4 kick past compression and back up) and may take a bit to find what it is.

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  • wr400mutt

Posted March 15, 2013 - 12:40 PM

#11

1'. i am getting fuel,
2. i did not do this swap original owner did, po couldnt figure out bike,
3. ive gotten the starting routine down and yes it is in a quad frame,
4. i have spark, took valve cover off last night inside the head looks great im going to check the valve clearance tonight
when i get off of work, from what ive been informed and read the intake clearance should 0.15-0.20 and exhausty should be 0.25-0.30
is this correct?!
5.the hot start isnt integrated into the carb it is mounted on frame,
6. the timing is good factory wr400 timing, i thought about doing light blue wire mod, and setting it to yz timing, but not sure, gotta new jew pj,
and main jet today, going to let carb soak while i check valves tonight,

  • Do I Care?

Posted March 15, 2013 - 03:45 PM

#12

1'. i am getting fuel,
2. i did not do this swap original owner did, po couldnt figure out bike,
3. ive gotten the starting routine down and yes it is in a quad frame,
4. i have spark, took valve cover off last night inside the head looks great im going to check the valve clearance tonight
when i get off of work, from what ive been informed and read the intake clearance should 0.15-0.20 and exhausty should be 0.25-0.30
is this correct?!
5.the hot start isnt integrated into the carb it is mounted on frame,
6. the timing is good factory wr400 timing, i thought about doing light blue wire mod, and setting it to yz timing, but not sure, gotta new jew pj,
and main jet today, going to let carb soak while i check valves tonight,


When you put the carb together, before fitting the bowl, fit bowl & hold it closed with your hand. Then connect your fuel line & wait for a few seconds & make sure it's not coming out the overflow before disconnecting it. Then check the float level. If it's okay (which it should be if the needle is clean & the needle seat o-ring is not perished). Next..
Fit carb together, connect to the fuel line. Check that it squirts fuel out from the starter jet. You will be able to see it squirt if it is in fact working. If not clean carb as described in an earlier post.

  • Do I Care?

Posted March 15, 2013 - 03:52 PM

#13

I hate editing so I thought I had better say. BE CAREFULL THAT PETROL DOES NOT SQUIRT IN YOUR EYES! This could cause some trouble (if you know what I mean) :lol:
If you want Yamaha manuals go to the Yamaha website by clicking HERE. It has very good info regarding the jetting,valves etc.

  • miweber929

Posted March 18, 2013 - 03:52 AM

#14

1'. i am getting fuel,
2. i did not do this swap original owner did, po couldnt figure out bike,
3. ive gotten the starting routine down and yes it is in a quad frame,
4. i have spark, took valve cover off last night inside the head looks great im going to check the valve clearance tonight
when i get off of work, from what ive been informed and read the intake clearance should 0.15-0.20 and exhausty should be 0.25-0.30
is this correct?!
5.the hot start isnt integrated into the carb it is mounted on frame,
6. the timing is good factory wr400 timing, i thought about doing light blue wire mod, and setting it to yz timing, but not sure, gotta new jew pj,
and main jet today, going to let carb soak while i check valves tonight,


So where are you at with this?

From your list above and with no follow up since I'd suggest again getting a baseline by making sure everything is hooked up right and transferred over from a WR, including the wiring harness and CDI. Make sure your carb is set up and functioning like was suggested earlier, though unless it has an aftermarket kit I don't remember the 400's having a hot start lever not mounted directly on the carb; you may have a different one on there. It's not a bad thing, but something to not.

Let us know what you found, search here for a service manual to verify valve spec.

  • wr400mutt

Posted March 18, 2013 - 09:19 AM

#15

I checked the valves myself and they were a lil to tight, so I adjusted the valves its starting fine, but the carb is still out of wack, but I cant find a rebuild kit anywhere,

it seems to be a 99 wr400 carb fcr with external hot start everything im reading about the 99 it comes with an external hot start
any ideas of where to get a rebuild kit

  • wr400mutt

Posted March 18, 2013 - 10:53 AM

#16

its a keihin carb has fcr on top of it

  • Do I Care?

Posted March 18, 2013 - 12:39 PM

#17

its a keihin carb has fcr on top of it

Well, you didn't read my post then lol.
The carb that is on my mates that I got going for him is a FlatCR (has it on top of carb). Still yet to find the external hot-start, but somehow I don't think that I will :)

  • wr400mutt

Posted March 18, 2013 - 01:58 PM

#18

Well, you didn't read my post then lol.
The carb that is on my mates that I got going for him is a FlatCR (has it on top of carb). Still yet to find the external hot-start, but somehow I don't think that I will :)



yeah i read your post and the hot start button is mounted on the frame and goes to the carb; therefore being external,
and did you get his bike going?

  • Do I Care?

Posted March 18, 2013 - 02:41 PM

#19

Yeah I figured that it was on the frame on your bike but I cant find it on my mates 99 model. Not sure how the hot-start integrates into your carb but there is none on this bike unless it's missing?
I did manage to get my mates bike going, but now it idles high at times & normal at others. Then TPS is unplugged as it makes it rev out too hard. I'm guessing that it is the fuel screw needs adjusting & it has the wrong size pilot jet. The fact that the float needs replacing isn't helping but not the actual problem I don't think. My mate had replaced it for a leaner PJ from a YZ so I will be putting the original one back in & adjusting the fuel screw.
Once I buy a new float for the YZ carb I will be installing that. It does run pretty good though for now.

  • MANIAC998

Posted March 18, 2013 - 02:57 PM

#20

A bad float will cause all kinds of jetting issues!!! This is the foundation that all jetting starts from, so the floats have to be set correctly or you will end up chasing your tail. FOREVER!!!




 
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