WR400F questions


14 replies to this topic
  • TTR-boy

Posted May 29, 2008 - 01:07 AM

#1

Well I havent posted on this site in years. Yet I am on now and again to read up but never post:bonk:

Some background(feel free to skip)
Well I bought a new bike about 3 months ago(finally graduated that TTR haha)

Its a 1998 WR400F bored and stroked to a 450 with high compression piston and rings, White brothers pipe, and some other little stuff. all I can say about the bike is WOW. I can hardly keep the front end planted :thumbsup:

I had a starting issue when I first bought it, I was told incorrectly how to start it with the decompression lever and after a snapped kick start lever and a swollen ankle, I finally was told how to start it properly. Now it starts first kick every time.:ride:

The problem
I let it run and warm up, turn off the choke and run it for however long. Well if I turn it off just long enough to slightly cool off, it is hard to restart. And god knows I dont want to be kicking this bike 100 times. Should I rechoke it at that point or not?

Weird question I know but it really boggles me. Ive never had this problem before.

Any input appreciated. Thanks alot guys:worthy:

  • matt4x4

Posted May 29, 2008 - 04:06 AM

#2

3 things are needed for a bike to run, fuel, spark and air.
Simple things first - have you replaced your sparkplug yet?
I presume you clean the air filter regularly - too much dirt or oil on the filter can inhibit the bike's breathing.
If the bike was stored any length of time, did you drain the carb - even then, it isn't unheard of for carbs to gum up or get some debris stuck in the jets.

  • creeky

Posted May 29, 2008 - 04:32 AM

#3

My WR400F is occasionally hard to start after shutting down for a few minutes. The problem is solved by using the hot start button.

  • TTR-boy

Posted May 29, 2008 - 07:24 PM

#4

haha I wish I had a hot start button lol.

I do clean the air filter regularly and cleaned the carb recently. I had issues in the past with carbs clogging up due to the ethanol in the gas, so now I only run race gas.

I havent checked the spark plug in a while, I dont know why but I will definitely check that out. Thanks alot!

  • SXP

Posted May 29, 2008 - 09:28 PM

#5

haha I wish I had a hot start button lol.


You do (unless it's been removed or you meant the "button" part literally). It's attached to the left side of the frame in between the carb and the air box.

It's the red knob with "Pull" pictured below?

Posted Image

  • TTR-boy

Posted May 29, 2008 - 10:09 PM

#6

really. I do have one of those. Its black but it is on my bike. How do I use it?

I always thought you had to pull that if you flooded the carb?

  • wobblyknobby

Posted May 30, 2008 - 12:09 AM

#7

You do (unless it's been removed or you meant the "button" part literally). It's attached to the left side of the frame in between the carb and the air box.

It's the red knob with "Pull" pictured below?

Posted Image


he is tricking you, do not pull it, it is the auto destruct button, or pull it and run like hell.

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  • matt4x4

Posted May 30, 2008 - 03:20 AM

#8

sxp - if that's your bike, cut about 1/2" off that fuel line, it's not looking too good!

  • SXP

Posted May 30, 2008 - 07:28 AM

#9

sxp - if that's your bike, cut about 1/2" off that fuel line, it's not looking too good!


It's run kinked like that since 2003 and never starved the carb for fuel.

I do get a lot of grief for that though:busted:

  • TTR-boy

Posted May 30, 2008 - 04:56 PM

#10

anyone want to explain how its used??:thumbsup:

  • SXP

Posted May 30, 2008 - 06:09 PM

#11

anyone want to explain how its used??:thumbsup:


If you stall/kill the engine while hot (i.e., not a normal engine shut down), chances are there's unburned fuel in the combustion chamber. So, you end up with a very rich condition which make re-starting the bike a biatch. This is where the hot-start comes in. Pulling the red knob opens up an additional bypass air circuit into the intake manifold, thus leaning out the mixture and making a "hot start" easier. As soon as the bike re-starts, push the red knob back in.

Make sure you don't mistake the choke knob (black) with the hot start knob (red).

  • husqvarnarider

Posted May 30, 2008 - 06:55 PM

#12

If you stall/kill the engine while hot (i.e., not a normal engine shut down), chances are there's unburned fuel in the combustion chamber. So, you end up with a very rich condition which make re-starting the bike a biatch. This is where the hot-start comes in. Pulling the red knob opens up an additional bypass air circuit into the intake manifold, thus leaning out the mixture and making a "hot start" easier. As soon as the bike re-starts, push the red knob back in.

Make sure you don't mistake the choke knob (black) with the hot start knob (red).


Well said..........:thumbsup:

  • kjr247

Posted May 30, 2008 - 07:05 PM

#13

IMO, when you get that WR REAL hot. You have got to let it cool a bit. If I cook mine, stall it... just have to wait. I have tried many things...I use the hot button but it is like the gas is boiling in the carb. With the 450 bore maybe it get a bit hotter. KJR

  • TTR-boy

Posted May 30, 2008 - 08:10 PM

#14

ahh ok I get it. Now that you have mentioned it, I did stall in once in the trails and it was tough to restart. Ill have to give this a try.

Thanks for the help guys:ride:

  • pdrides

Posted June 01, 2008 - 04:12 AM

#15

Yea, don't despair. These bikes are notorius hard starters untill you figure out what works best w/ yours. It wasn't untill after I got my bike really dialed in that I got the full benifit of the hot start. Now when I need to restart when it's hot... 1 kick and I'm off. Just make sure you push it back in right away after it starts, it wont hurt it or anything , it'll just run like crap.




 
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