2000 YZ 426 Question


15 replies to this topic
  • Driftingokie

Posted November 04, 2009 - 09:20 PM

#1

My brother bought a 2000 YZ426 at a auction the other day. Got it real cheap. We have no history on the bike. Here is the problem: It will not start. The thing is almost impossible to kick without pulling the decompression lever. Any ideas why it would be so hard to kick? I havent checked anything on it yet. Just tried to kick it a few times.

Edited by Driftingokie, November 04, 2009 - 09:40 PM.


  • grayracer513

Posted November 04, 2009 - 09:50 PM

#2

That would be normal, and it's why the bike has a compression release.

http://www.yamaha-mo...troke_vid_a.mpg

http://www.yamaha-mo...troke_vid_b.mpg

  • jzb

Posted November 05, 2009 - 08:14 PM

#3

There is a nak to starting those bad boys, hold the comp. release and kick the thing over about 5 times, let the comp release off and kick it real easy till it feels like it locks up pull the release again and kick it all the way down , let the kicker up dont touch the release or the throttle and kick. good luck, they are a bugger 2 start. I 4got to tell u whan u go to kick it after you find top dead center pull the compresson release and move the kicker down just a hair then let the release go and kick. I found on mine if you twist the throttle at all it will foul the plug right now. just use the choke.

Edited by jzb, November 05, 2009 - 08:40 PM.


  • keepinon

Posted November 05, 2009 - 08:39 PM

#4

They also don't like anything less than FRESH premium fuel. The plug may also be fouled.

  • Driftingokie

Posted November 07, 2009 - 04:46 PM

#5

I got the beast started!!!!

Now I have some more questions.
After I got it started it was backfiring bad(popping), and you had to stay on the throttle or it would die. But I did get to ride it around for about 5 mins. and everything seemed to be ok on the bike.
The question is: with it backfiring like it was, would that be spark plug fouled or carb setting?
Next question: Explain to me how this oil thing works. The oil tank is in the frame? And you add as needed? Looking at it, it looks like all the oil you add would go till the engine was full. I have never seen a dip stick up on the frame like that.
As you can tell I am new to dirt bikes. My son has a CRF250R and the dip stick is on the engine.
Any help would be appreciated.

  • cwcarter

Posted November 07, 2009 - 05:16 PM

#6

Sounds like your pilot jet is clogged. They use a dry sump oil system. You must run the bike for a few minutes so oil gets pumped back to the frame. Only then you can check oil level with the dipstick.
Here's the manual http://www.yamahaown...om.au/index.php

  • grayracer513

Posted November 07, 2009 - 05:30 PM

#7

Backfiring:

http://www.thumperta...599#post3710599

Idle speed is set with a black knob on the left side of the carb. Turn the knob clockwise until the engine will idle at a stable speed.

Then, adjust the idle mix:

http://www.thumperfa.../jetting.htm#PJ

On the oiling system:

http://www.thumperta...903#post5221903

All of this info and more came from the Common Threads/FAQs sticky, the first thread at the top of the index for this forum. Browse through it.

  • Driftingokie

Posted November 07, 2009 - 07:07 PM

#8

Thanks for the help

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  • divebobber

Posted November 09, 2009 - 12:07 AM

#9

with it backfiring like it was, would that be spark plug fouled or carb setting?

Along with the jets, make sure your hot start knob (red one on the carb) is not stuck in the open position like mine was. Makes it run real lean for starting when hot. Water can get in there and freeze them up.

  • ninthrazor

Posted November 18, 2009 - 12:08 AM

#10

I got the beast started!!!!

Now I have some more questions.
After I got it started it was backfiring bad(popping), and you had to stay on the throttle or it would die. But I did get to ride it around for about 5 mins. and everything seemed to be ok on the bike.
The question is: with it backfiring like it was, would that be spark plug fouled or carb setting?
Next question: Explain to me how this oil thing works. The oil tank is in the frame? And you add as needed? Looking at it, it looks like all the oil you add would go till the engine was full. I have never seen a dip stick up on the frame like that.
As you can tell I am new to dirt bikes. My son has a CRF250R and the dip stick is on the engine.
Any help would be appreciated.

I have a 2000 YZ 426. The oil in the frame took me for a bit of surprise as well. When you drain the oil, drain the case AND reservoir. Then fill the reservoir to just below the required amount...maybe .2 quarts or so. Run it for 30 seconds, check for leaks. Kill it and let it sit for 10-15 seconds. Then recheck oil level, top off as needed.

The easiest way to kick it over is just as the others have said. This is what I have found works awesome for me. First start of the day, pull the compression lever and hold while kicking the bike over 5-6 times (thus clearing out any fuel, etc.). Release the comp lever until it feels as if it has "locked" up. Bring the kick lever full up and pull the comp lever while moving the kick lever down an inch or two. Release comp lever, bring kick lever full up again, then give it heck!! My bike starts first most times, someitmes takes a second kick. If it takes a third, I get upset because I know I screwed something up :excuseme:

Hope this helps a bit.

  • ninthrazor

Posted November 18, 2009 - 12:11 AM

#11

I have a 2000 YZ 426. The oil in the frame took me for a bit of surprise as well. When you drain the oil, drain the case AND reservoir. Then fill the reservoir to just below the required amount...maybe .2 quarts or so. Run it for 30 seconds, check for leaks. Kill it and let it sit for 10-15 seconds. Then recheck oil level, top off as needed.

The easiest way to kick it over is just as the others have said. This is what I have found works awesome for me. First start of the day, pull the compression lever and hold while kicking the bike over 5-6 times (thus clearing out any fuel, etc.). Release the comp lever until it feels as if it has "locked" up. Bring the kick lever full up and pull the comp lever while moving the kick lever down an inch or two. Release comp lever, bring kick lever full up again, then give it heck!! My bike starts first most times, someitmes takes a second kick. If it takes a third, I get upset because I know I screwed something up :excuseme:

Hope this helps a bit.

Oh and one more thing...DO NOT GIVE IT ANY THROTTLE WHEN STARTING!!! This shouldn't cause any "damage" per say, but it will fail to start. The reason is that you have an "accelerator pump" on the bike and when you give any throttle input (bike running or not), it squirts a steady stream of fuel into your carb. Thus creating a "flooding" condition. Have a good one and enjoy the bike!!!

  • DrThumper

Posted November 18, 2009 - 09:49 AM

#12

Backfiring alot? Maybe your using the hot start instead of the choke. On the older bikes, the hot start is red, the choke is behind it and black.

My '00 426 has never fouled a plug in 9 years. In fact, I've never fouled a plug on a 4 stroke, ever. That's a 2 stroke thing.

  • l_campionero

Posted November 18, 2009 - 09:51 AM

#13

+1 on the 426 not fouling plugs, but my '98 400 would foul one worse than any two-stroke I ever had! When it started snapping and popping, I had to head back to the truck IMMEDIATELY, because it was going to stop dead soon!

  • ninthrazor

Posted November 18, 2009 - 12:59 PM

#14

Backfiring alot? Maybe your using the hot start instead of the choke. On the older bikes, the hot start is red, the choke is behind it and black.

My '00 426 has never fouled a plug in 9 years. In fact, I've never fouled a plug on a 4 stroke, ever. That's a 2 stroke thing.

On my YZ 426 F, yes the "hot start" is only used for starting the bike after it has been running and you kill it from lack of throttle to horsepower-need demand :excuseme: Used to happen to me all the time. The hot-start lever is red...do not use this to start the bike cold only use the choke lever which is black. Also, if you end up using the hot-start feature, which you will, after you get the bike started, DO NOT RUN THE BIKE WITH THE HOT-START LEVER PULLED!! I cannot stress that enough. Yes it leans out your fuel mixture a lot, but can, over time if misused, cause engine damage, so my mechanic says :bonk:

  • grayracer513

Posted November 18, 2009 - 02:08 PM

#15

DO NOT RUN THE BIKE WITH THE HOT-START LEVER PULLED!! I cannot stress that enough. Yes it leans out your fuel mixture a lot, but can, over time if misused, cause engine damage, so my mechanic says :excuseme:

Your mechanic is wrong. In the first place, the engine would run so poorly underway with the hot start pulled that no one with any sense would not stop to see what the problem was. Secondly, four-stokes are far more tolerant of lean mixtures than two-strokes are. There's no real risk of engine damage from running with the hot start open.

  • ninthrazor

Posted November 18, 2009 - 06:39 PM

#16

Your mechanic is wrong. In the first place, the engine would run so poorly underway with the hot start pulled that no one with any sense would not stop to see what the problem was. Secondly, four-stokes are far more tolerant of lean mixtures than two-strokes are. There's no real risk of engine damage from running with the hot start open.

noted...thx





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