Pls help new YZ426 1st 4 stroke many problems

30 replies to this topic
  • shanet1975

Posted April 04, 2005 - 02:43 PM


I have recently purchased a used 2001 YZ426. I have owned many 2 strokes, but this is my first 4 stroke.
Issue1-It took me about 30 minutes to get it going yesterday and today. I've been following the steps to the T. Pump til stopped at the top, pull in lever, pump another inch or 2, release kicker, release compression lever, then kick through. After getting awefully tired and p1ssed I started trying like the old 2 strokes. A little throttle. After a few more kicks she fired up.
Issue2-It think this may be connected to issue 1. I shut off the gas and she stayed running for over 5 minutes. I read somewhere that people let her run out of gas in the lines for easier starting the next time. Maybe theres that much fuel in the line that it'll run that long. Shut it off because......
Issue3-Muffler was getting red hot at the motor. Kinda scary. I think I got ripped pretty good on this bike unless I just don't understand the way these 4 strokers are. Forewarning, not very mechanically inclined...
Any help on any of this would be greatly appreciated.....

  • shanet1975

Posted April 04, 2005 - 02:50 PM


One other thing....I have antifreeze leeking too........Forgot about that.....Is it time for the shop already????

  • Thumpy79

Posted April 04, 2005 - 02:57 PM


Here's the starting proceedure for the first start of the day:

1. Turn on Gas - Pull the choke
2. Give the throttle two twists
3. push the kick start down until it stops
4. pull the decomp lever
5. Push the kick start down an inch
6. release the decomp lever
7. Bring kick start all the way up and kick it through

It seems like a lot, but is really easy.

The Red hot pipe is normal, it happens to all of them.

If you let it sit while running or go real slow for a long period of time it will over heat and lose radiator fluid.

  • shanet1975

Posted April 04, 2005 - 03:01 PM


Thanks for the input....So this is by no means a trail bike huh? As long as I'm moving along will I be okay. I live in MA so the rails we have you can get moving pretty well on.
Is it normal for the bike to keep running even after I shut the gas off?
I followed that procedure and it still took quite some time to get it going. Should I always use either the choke or the hot start? How bout both, or neither?
Thanks again......I love the power and speed, I just hate the aggrivation of starting it......

  • kizzle426

Posted April 04, 2005 - 03:55 PM


I just bought my first 4 stroke a couple of months back. It's an '02 426. I leave it running with the gas off and it takes a while for all the gas to get out of the carb. It's totally normal. 2- strokes empty alot faster because they are firing twice as much as 4 strokes. starting is not that bad. Here's a tip that helps me out a lot. If it doesn't start after about ten tries, turn the gas off. Then, pull the decomp lever and hold the throttle open all the way. Kcik through with the decomp lever and the gas open all the way about 10 times. Then, trun the gas back on and follow the normal start up procedure. If it's cold, choke it. If it's hot, hot start. Nobody real puts that tip on here too much so that ought to help you out. The gas wide open with the decomp pulled empties out the carb and the fuel in the cylinder. The bikes are easy to flood. NEVER pull the throttle while attempting to start it. Do that on accident and you'll have to do the procedure I just layed out. Also, 426's are pretty good for trails. I race motocross and I ride trails. If you want full on trails, get a heavier fly wheel and drop the idle down a bit. Voila!! You will have a wr without the headlights. Enjoy the bike my friend. I love mine!!!

  • 02YZ426

Posted April 04, 2005 - 03:57 PM


First of all, I would put a new spark plug in the bike. That should help, because who knows how old it is and how many time its been fouled up. If you want to empty your carb out after riding, then just shut the fuel off, and open up the allen head bolt on the float bowl. That will let the gas drain from the carb, and you wont need to run the bike for 5min to empty it. :naughty:

  • Chipstien

Posted April 04, 2005 - 03:59 PM


The bike is going to keep running untill all the gas in the float bowl is gone. Can take quite awhile before it dies.

As said, the pipe is normal.

As for hard starting... you will prolly need to jet the bike properly before it will start easily when the weather is cool. As the weather warms up the bike will start much easier.

As for the starting drill... don't sweat it. It will take a couple of rides until you have it down but once you do it will become second nature to you. However if the drill really gets to you then buy a 450 cam and drop it in. Then the starting drill is the same as a 2stroke. :naughty:

  • 02YZ426

Posted April 04, 2005 - 04:03 PM


Ya...definaty a good idea to do the 450 cam upgrade. I can start my bike sitting down on the seat. :naughty: No more bruised bottoms of the feet either. :naughty:

  • 642MX

Posted April 04, 2005 - 04:14 PM


Ya...definaty a good idea to do the 450 cam upgrade. I can start my bike sitting down on the seat. :naughty: No more bruised bottoms of the feet either. :naughty:

You beat me to it. The 450 cam will solve the majority of starting problems.

  • shanet1975

Posted April 04, 2005 - 04:18 PM


Sounds like all my symptoms are normal. Good to hear. Thank you all for the input. Bunch of helpful folks here...About the 450 cam mod. Easy to do? Even if I'm not good at wrenchin'? ow much is this mod and where abouts do I look? Sounds much better than the way it is now. I'm sure after a few times out it will get easier. Thanks for the draining the fuel tip with the gas off. I'll definitely try that. It is still a little cool here in Mass. Are these impossible to start when winter comes?
Again, thank you all for your helpful input....

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  • 02YZ426

Posted April 04, 2005 - 04:22 PM


They are easy to start in the winter if you re-jet your carb for the cold. Usually 2 twists of the throttle then kicker over and fires right up. There is a ton of info on the cam upgrade in this forum. Look at the top of the front page.

  • 642MX

Posted April 04, 2005 - 04:23 PM


Mine starts fine when its cold. Do a search on this forum about the 450 cam mod, there are probably a zillion posts on that topic.

  • shanet1975

Posted April 04, 2005 - 04:29 PM


Will do. Thanks again....I'll have to search on oil changes too. Didn't come with the manual or anything so I'll check on that as well.
Thanks again....

  • buck_y_lee

Posted April 04, 2005 - 04:40 PM


When you kick, kick strongly all the way through. A strong, steady, FULL kick and the beast will roar. Short two-stroke-like jabs and she'll laugh at you for being a girly-man.

I never use the throttle, though I am probably in a more moderate climate than you.

Use the choke when cold, nothing when warm, hot start when hot, stalled or dropped.

  • shanet1975

Posted April 04, 2005 - 04:47 PM


So 450 cam mod or no???? I did a search and am seeing that there may be some long term things to worry about. Things not being the right size and lining up quite right. It would be quite nice to just be able to kickstart it without having to think about what I'm doing....Didn't see anywhere yet as to how to make the change. Is there a step by step site that walks you through the mod? Any websites anyone recommends that carries the cam?

  • buck_y_lee

Posted April 04, 2005 - 04:56 PM


No mod for me. This bike is the easiest thing in the world to start. No more than three kicks ever. I even filled it with water a couple of weeks ago and she still fired up.

Seriously, get the drill down, understand what the hot start and choke do and you won't have a problem. I can think of many better things to spend a few hundred bucks on.

  • 02YZ426

Posted April 04, 2005 - 05:00 PM


No mod for me. This bike is the easiest thing in the world to start. No more than three kicks ever. I even filled it with water a couple of weeks ago and she still fired up.

Seriously, get the drill down, understand what the hot start and choke do and you won't have a problem. I can think of many better things to spend a few hundred bucks on.

If you had one on your bike you wouldnt be saying that. No way in the world is the bike easier to start without the mod!. :naughty:

  • buck_y_lee

Posted April 04, 2005 - 05:06 PM


OK, easiest thing in the world except for a yz with auto decomp. Still, it's dead easy and to me a waste of good money.

If you're a serious racer and you want to save yourself 2.5 seconds after a crash, then do the mod (if you're that serious you'd be riding a newer bike anyway). Otherwise, if you're a weekend rider, why on earth would you bother with the mod if you don't have money growing on a tree?

  • grayracer513

Posted April 04, 2005 - 05:08 PM


Yes to just about everything said.

I can trail ride my 450 for a ridiculous distance with the gas off (don't ask), I can only imagine how long it would idle. Certainly long enough to turn the pipe red and boil it over. I don't really see that the bike will start any easier for draining the carb unless it sits for several weeks at a time.

The Decomp cam and the '01 clutch mods are the best money you'll spend on it. In the meantime, a picture is worth a thousand words, and a video is a thousand pictures.


  • 02YZ426

Posted April 04, 2005 - 05:15 PM


In most cases you are saving more than 2.5 seconds after a crash. More like you are saving LAPS rather than seconds. I agree that you can start the bike easy if you know the drill, but I'm just saying why even bother with it if you dont have to? The upgrade isn't that expensive anyway. It cost me only $230cdn. for the HotCam, and thats the best 230 I've ever spent. In fact, I would pay double that if thats what it cost. Save the leg! and do the upgrade.

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