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YZ250f won't start... help?!

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Posted by: stormer94---------------------

I've owned like 50 bikes, I'm no rookie. I understand that the new yz250f requires a different technique. So I read the manual back and forth. And feel I have a good handle on it.

I'm still on the first quart of gas mind you. I got it to run yesterday and I ran it for about 45 minutes. This Morning I tried to get it to run, and it took about 10 minutes of kicking to get it to go. At 2:30 this afternoon I thought I would go home, ride till dark and that would be about the end of it as the snow is about to fly. I kicked that thing from 2:30 to 4:30. 2 HOURS!!!! I suppose on a purely exercise related case I got more bang for the buck than if I had actually ridden it, but that's not gonna last forever, I WANT TO RIDE IT!!!

Here's the drill. It's got fresh gas in it. I check and also turn the gas on. It's about 50 degrees outside, but nice. I pull the cold start lever and kick until I get the compression stroke...NOT the exhaust stroke. I pull the decompressor until the kickstarter moves about 20 degrees (let go of the decompressor), let the kickstarter return and KICK. (repeat for 1/2 hour). I'm taking great pains to see that I am not accidentally cranking on the throttle by even going so far as to put my throttle hand on the crossbar so I can't accidentally flood it.

I decide that maybe it needs cleaned out or something. So I pull the decompressor and kick it 20-30 times with the hot start button out and the cold start button in.

Repeat kicking for another 60 minutes... :scream: with a few random minutes where I would take some time off and lay on the ground wheezing...

At the 90 minute mark, I check the plug... It looks like a plug, not wet, slightly black. I put in a new plug (an interesting ordeal on it's own). Repeat 10 minutes of kicking and me hunched over the bars, wheezing and then finally giving up... (insert total disgust). I very carefully push the bike back in the garage with what little strength I still have. I really wanted to beat it with a sledge, but resisted. I maintained my calm and here I am asking for ideas.

I've decided that maybe the gas I put in it is 87 octane. The manual says 95. So I brewed up a batch of 95 and am about to drain the gas and try that. I can't imagine that is the problem, but I'm willing to try about anything at this point. Other than that, I'm stumped.

Maybe I need an exorcist.

I'm at 2200 feet in elevation if that matters.

My back hurts, my right foot and leg are KILLING ME. And when I'm done stuffing this bike in somebodies ARSE at the Yamaha shop I'm gonna feel a lot better.

Any ideas... Anybody?


Posted by: Mxer426---------------------

this has always worked for me. when the bike is cold dont touch the hot start button, and dont touch the throttle, pull out the choke, kick to top dead center (TDC), when you get there, turn the engine over very little and kick, repeat until cranks
this method has never faild me yet, and just to make sure just start with a new plug just to make sure and make sure your filter isnt overlubed.


Posted by: holeshot---------------------

The 95 octane listed in the Yamaha manual is RON (Research Octane Number) , which is about 91 or 92 pump octane. I doubt if your problem is the gas.


Posted by: oabike---------------------

I had an 01 250F.

Try this...when it is cold,give it 2 blips of gas before you do the start drill. If you do flood the carb you can drain the bowl by turning off the gas and tipping the bike over or you can unscrew the 3mm allen head and the gas will flow out of the bowl. Try turning the fuel screw in or out depending on your altitude and temp.

You can also try this...when it is cold, pull the hot start and give it gas like a 2-stroke. It worked for me in a pinch.

You can always...bump start it using the decompression lever QUICKLY.

The good news is...the bike WILL start easier after a few tanks of gas.

The bad news is...the bike is tempermental. There will always be a starting drill. Yamaha needs to work on this . It is unforgiveable.

Investing in a BBR kickstarter and doing the BK mod to the carb will aid in starting too.

On a side note...I put a Dubach pipe on mine and it is the best mod you can do for performance. They are coming out with a cool airbox too.


Posted by: biglou---------------------

Stormer-I've got to say that I had a chuckle at your expense here! Sorry!

A couple of ideas: Are the carb settings as they should be? (ie: pilot screw, idle adjust at x.x turns out, etc.) I'm also thinking you could have some debris lodged in the pilot jet or a journal somewhere. You say it started once, so I would assume (possibly incorrectly) that there is spark.
Remeber, it takes three things: Fuel, spark and compression. Not to over-simplify this or anything, I realize that these three things are each very complicated in themselves.
Sorry I can't be of more help. It really pains me to see someone have this much trouble. All the myths I had heard about starting the 4-stroke yammies have been laid to rest for me in the last year. Several of my riding buds ride them and both they and I can most times start them in one kick, hot or cold. I realize you probably already know this, but I'm willing to bet that something is out of adjustment or otherwise not just right. The problem is finding that needle in the haystack. Best of luck.


Posted by: MikeOK---------------------

Yo stormer- this may not help you start your bike but it may make you feel better... Try doing the same thing but on a 426, in the middle of a moto after a stall on an Oklahoma track on a day when they were saying it was 112 degrees!!! To make it worse the old chuckle-headed vet riders made sure to blow a bunch of dusty roost all over me as they went by lol... Tears would have been running if I weren't so hot and dry...


Posted by: ACS---------------------

Screw up the idle a fair way and make sure the fuel screw is set to the factory specs. It should then start. They idle fast but its the only way. As others have said they are much better when run in.


Posted by: IBWFO---------------------

Just to get ya goin' try getting someone to pull ya so you can "Push-Start it.
The one thing I do when I have a problem (426) is to shut the gas off, then hold the throtle wide open and kick it over say,...........15 times. Then go back to your normal starting routine, but leave the gas off until it starts.
Regards


Posted by: stormer94---------------------

The idle thing sounds like a good idea, I was thinking about that as well. I might try that.

I decided that no two wheeled demon is gonna get the best of me!!!! So after dinner I went out to try it again. It's now about 45degrees in the garage. I turned on the gas, did NOT pull out the cold start nob. I had previously decided to call that the choke. Yamaha calls it a cold start knob. It's not that I'm smart or anything, I actually forgot to pull the knob. So I give the throttle 4 full twists. I kick it 4 times and it makes a gurgle, I was so happy I nearly wet myself. I pulled the cold start nob and within 10 kicks it finally started. :scream:

I rode it around for about an hour. Killed it twice, and it started second kick the first time I killed it. Started the second time the first kick. I actually got brave and shut it down on purpose, and dang if it didn't start up again. The last time I shut it down to chat with some buddies, I started it WITHOUT the hot start button after it sat for about 15 minutes... first kick. I think I can hot start the thing now. But I'm still dubious as to the method for when it's cold.

I think I'm gonna try this tomorrow. 3 twists of the throttle, 2 kicks WITHOUT the cold start knob, wave my MAGIC chicken foot over the carb, say a few hail Mary's, then pull the knob and kick till it fires.

I sure enjoyed it when it ran, so I'm willing to put up with it. My back is frickin KILLING ME!!! Gonna take 30-40 ibuprofen and go to bed. :confused:


Posted by: yz250-effer---------------------

When I first got mine last year, the first ride consisted of 1 hour of kicking my leg and foot were jello. They are just hard to start when brand new for some reason? After 2 or 3 rides you will do everything the same as on the first ride from hell, and it will fire right up.

I only do one thing different. When it is cold I give it one "teeny" blip ( very teeny ) and then pull out the choke. THen I get it to TDC and use the comp. release to go just 1 inch ( I think that is less that 20 degrees). THen I bring the kickstarter ALL the way to the top and kick forcefully, but not too fast and let my foot stay on the bottom of the stroke. If you bring the starter up too quick the dogs engage and can kill the motor right when it was about to start.

After 3 rides I never had a hard time starting it and I would tell friends, " If you can start it, you can ride it! " Cuts down on the free rides


Posted by: MWEISSEN---------------------

Just a couple more tips on starting, learned from owning a WR400F and a Yz250F:
1. When new, both of my bikes were a bear to start. With break-in time, they both got easier.
2. Both react identically - when cold, a twist of the throttle helps "prime" the engine.
3. When they don't start within 4-5 kicks, they're usually full of gas. I've NEVER got the pull-the-compression-and-kick-20-times routing to work. What works for me when warm is to also pull the hot-start button to give the engine a shot of lean air.
4. When REALLY flooded badly, a fresh plug is in order. After pulling out the plug, turn off the gas and kick the engine through to blow out the gas still in the engine. When cold, and I just want to get the thing going, I've loosened the air cleaner and shot the carb with starting fluid. THEN the thing will start first kick!
So far I've found the 250F more tempermental in the cold to start than the 400 to start. And the 250 seems to not like more than one twist of the throttle.

Hope these help too!


Posted by: biglou---------------------

Don't crank on the throttle too much when it's cold or you will flood it.
Cold: Gas on, choke on, one tiny blip (Maybe) then bring her just past TDC and kick it like you own it!
I've read in here somewhere about gas on the cylinder walls compromising the seal between the rings and the wall, thus killing one of your three required situations for starting: compression.
Also-Double check your adjustments to the carb and set the idle up once she's warmed up. That should help you from this point forward.
Glad you got her goin'!


Posted by: stormer94---------------------

Thanks for the help guys.

I've ridden know a few times and here's what's working.

It's like 40-50 degrees here right now, and I ain't gonna quit riding till the snow flies!!!

When cold, like in the morning, I crank the throttle 4 times. do the decompress routine and try and kick it 3-4 times. If no fire in the hole, I pull the cold start button and it will start on the 3-4th kick.

When hot. I pull the hot start and one good kick and she's runnin. I've even been able to start it 50% of the time without the hotstart. Usually seems like it will do it if I come to a stop and kill it. Kill it on the trail and it seems like I need the hotstart button.

I'm getting more comfortable with the routine, and really enjoy the bike. I'm thinking about putting the clutch perch and decompressor lever off the CRF450F on the thing. I like how compact it is. I can't see why it wouldn't work.


Posted by: oabike---------------------

If I get a Works Connection unit I'll sell you mine. The little lever on the 450 is a hot start. I'm not sure the cable travel/throw is the same. Check it out and let me know.


Posted by: hoosierf---------------------

Here goes boss, the end of your troubles. Your bike is a little bit lean. Turn your pilot screw 1/4 to 1/2 turn out and the gremlin will light much easier for you. The giveaway is the blipping of the throttle 4 times then it is cold.

I made a pilot screw tool by pressing a wire nut with an aluminum insert onto a screw driver bit like you would use in a drill. Turn the pilot screw out, you won't be sorry. You need the blips of the throttle when it's cold to get enough fuel to light it up.

There's no magic to riding it more and then it will suddenly start easier. You get better at starting it! You don't break the bike in, it breaks you in.

If it starts hard in the spring when it warms up, you'll need to go in on the pilot to reverse what you've done. Good luck.


Posted by: hoosierf---------------------

Here goes boss, the end of your troubles. Your bike is a little bit lean. Turn your pilot screw 1/4 to 1/2 turn out and the gremlin will light much easier for you. The giveaway is the blipping of the throttle 4 times then it is cold.

I made a pilot screw tool by pressing a wire nut with an aluminum insert onto a screw driver bit like you would use in a drill. Turn the pilot screw out, you won't be sorry. You need the blips of the throttle when it's cold to get enough fuel to light it up.

There's no magic to riding it more and then it will suddenly start easier. You get better at starting it! You don't break the bike in, it breaks you in.

If it starts hard in the spring when it warms up, you'll need to go in on the pilot to reverse what you've done. Good luck.


Posted by: Boozer---------------------

give it time. my 250F was an absolute disaster in terms of starting when new. the only way to start the thing when cold was to use the choke and hot start button at the same time. started without a drama. after it was broken in, it started second kick with just the choke. give it time and it will come good.


Posted by: stormer94---------------------

hoosierf,
Quote:
There's no magic to riding it more and then it will suddenly start easier. You get better at starting it! You don't break the bike in, it breaks you in.


Amen to THAT!!!!


Posted by: mxracer724---------------------

You know I have had my 250f for almost a year now and still can't start the thing when it is cold! It bugs me so much. I don't know what I'm doing wrong. Don't laugh when I ask I've been riding for over 2 years and no one has really explained what top dead center is when you are starting it.

Anyways, can some one tell me what that means? Thanks


Posted by: biglou---------------------

Top Dead Center, or TDC for short, is when the piston in at the very highest point it can travel to inside the cylinder. You want it to be just past TDC before you kick it so you don't break your leg or the kick starter trying to push the piston past TDC on the compression stroke. This is why you kick it until it essentially stops due to the compression, pull the decompression lever and let it go just a bit further (past TDC) so that the piston is on the down-stroke before kicking it.


Posted by: biglou---------------------

I did just remember one thing: I have heard of a couple guys having their pilot screw back out on them, some to the point of even falling out. I'm not sure how prevelant a problem this is and I'm not sure what the fix was, but it is something that you might want to keep an eye on.


Posted by: WRecker---------------------

Stormer94, you'll probably get it started with fewer kicks if you DO use the choke from the get-go. My drill for starting my WR250F is: choke on, gas on, kick just past TDC using the comp. release, and 2-3 full twists of the throttle to prime the cylinder, then kick. It will start on the second kick 98% of the time. The other 2% of the time is usually due to a boneheaded maneuver on the owner's part. If, during your struggle to start it, you find gas dribbling out of the vent tubes onto the ground, shut the gas off and lean the bike over on it's side to completely empty the carb. Then, start over, only this time don't touch the throttle.

The one problem I DO have from time to time, and maybe somebody can shed some light on this, is I have intermittent success with using the hot-start button when the bike is hot. Sometimes it needs it to start, sometimes it doesn't. And it seems like if I make the wrong choice in whether or not to use it, I end up kicking the bejeezus out of it to get it going again. Any suggestions?



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