YZ426 Trouble starting. STILL!!

Hey everyone. im still having major problems with my 426. it wont start! Today it took me 30minutes. i kicked and kicked until my face was blue. Finally it back fired. and 5 kicks after that it started kicking over. it would sound like it was going then would die. sound like it would start then die and so on and so on for 10 kicks Then finally started up. the bike couldnt have been flooded. because the last time ih ad started it i turned the gas off and left it running until it ran out and died on its own. ive changed out my spark plug. i dont know what else to do to get it working. any idea's? im probably going to take it to the shop sometime but any help would be much appriceated.

How much oil do you have in that air filter? I had that problem a few times when I overdid it with the oil.

>Air filter is a good start.

>Also check to make sure you are not twisting the throttle by accident when going to start it.

>What is your current jetting?

>Have you done the BK mod? If so, did you update the jetting to coincide with the mod?

>Old gas? Bad gas?

>When you get it started turn off the choke within 10-15 seconds (or less)

Hope some of this helps you.


Done all that, No mods. stock jetting. worked fine a month ago then all of a sudden out of the blue it started doing this

maybe your fuel line is cloged up a bit. try cleaning out you carb and jets run some carb cleaner in with your gas.

just a thought

What is the temperature overthere ? What about when engine hot how difficult was it to restart?

To me I think you have cloged up jet,take carburator

out and blow with compress air and double check with carburator cleaner just to make sure that all jets unclog.It happen to me before.

Good luck


The temp have been in the 60's and 70's around here.

You might try giving it two twists of throttle before you attempt to kick the bike. Mine requires that she will fire up the first or second kick. If I don't then it can take 5-10 kicks with the light,die that you described.

If you are still having problems let me know and maybe we can meet up to look at the bike.

Hey scott. I Usualy do give it 1 or 2 blips of the throttle. still doesnt start up. its just weird it was working fine a month ago but right when the weather changed. it just stopped working right. i dont know if its because of the weather or something else. and ive tried everything i could think of. If you have time sometime it would be great to meet you and to take a look at my bike since the fact i know nothing about it as far as working on it. If you want to get ahold of me email me at reed@kc.rr.com or just ask for my number and you can give me a call.

[ November 16, 2001: Message edited by: reed YZ426 ]

I'm new to 4-strokes myself, and had a lot of problems starting. Fuel on, No choke, maybe a blip of fuel. Here is what has been working for me: I turn the Idle knob 1 full turn Clockwise. This seems to help the motor 'catch' when kicking over. After it warms up, I return the idle back.

Good Luck.

P.S., I try to park on hilltops, to give myself a rolling start!!!

I also like to give the idle screw a turn or two when cold starting. If I do that and follow the drill it starts even in 25 degree weather.

Have you ever had the valves checked on your bike

My 01 426 had a really tight exh valve which made it hard to start and it would pop and backfire when it would first start up. maybe yours doesnt backfire but it might be why its so hard to start.

Riding Tips


There is no doubt that the Yamaha YZ-F will encourage lots of new riders into the four-stroke fold. The rite of passage for any neophyte four-stroke rider is starting one of the beasts. The golden rule--tattoo this on your forehead is: "Thou shall not touch the throttle at any time during the starting process."

If you are smart, you will do exactly what we tell you. If you’re not smart...good luck.

Step one: With the transmission in neutral, turn the gas on and pull the choke out.

Step two: Kick the engine through slowly until you come to the hard spot (where the kickstarter will not move). This is called "bringing it up on compression."

Step three: Once you have brought it up on compression, follow these three steps: (1) Pull the compression release in. (2) Move the kickstarter about one inch past compression. Do not move the kickstarter so far that the piston goes through compression and moves too far down into its intake stroke. A little dab will do ya. (3) Once you have nudged the piston over top dead center, allow the kickstarter to return to the top of its arc.

Step four: Release the compression release.

Step five: Kick with a steady but full stroke (from the top of the kickstarter’s arc all the way until the kickstarter hits the footpeg). If you did everything as prescribed, the YZ-F will start. However, if you touched the throttle, it will not.

Throttle tip: instead of holding onto the throttle with your right hand, hold onto the brake master cylinder.

Hot starting tip: Pull the hot start button out and follow steps one through five. Push the hot start button in as soon as the engine starts.

Cold start tip: Before you start the YZ-F for the first time, give the throttle two little blips. This will put a small dose of fuel into the top-end. No more than two blips. Never blip the throttle before starting a hot or warm engine.

Enemy tip: If you don’t own a YZ-F but want to ruin the day of a YZ-F rider who you don’t particularly like, go over to his unstarted YZ and give the throttle four or five healthy twists. The accelerator pump will fill the engine with fuel and it won’t start until the following Thursday.

The word: The Yamaha YZ-F isn’t the easiest starting full-size four-stroke engine made--that honor goes to the KTM 520SX or anything with an electric starter, but the YZ-F will start every time--if you follow the drill..


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