starting problem

just purchased 02 yz426. Here is the deal, when I first got it, it would start second or third kick, now it takes about fifteen, then it has to be warmed up to idle without the choke on. Just changed the break in oil. Any ideas or help????? Would changing the plug work or is there more to it.

Try first changing the plug and checking it's condition ! Also you can try changing the carburetor needle settings, I don't know too much about jetting but sometimes is the clue to starting problems, also check the air screw and play a little with it until you reach the right idle speed !

Hope this helps ! :)

Do a search for "blue wire" and "bk mod" these 2 things might help you out!

BTW You made sure your airfilter was clean right? If so you made sure you didnt over-oil it (this also can cause hard starting)? Im assuming your jetting is stock right? Good Luck and Welcome to TTalk,



I would like to suggest the more 'conservative' approach. I see no reason that a new bike with stock jetting should have this type of trouble. If you just bought it...have the shop take a look. They should take care of you and not charge anything. I would do this before messing with the jetting and such. Now, that's just me and you might want to dive in and tweak stuff but I'm running the stock jetting after a year on my 01 and have never changed a plug. I will give you the benefit of the doubt and assume you are "following the drill."

For what it's worth,


[ March 27, 2002: Message edited by: eBayThumper ]


The answer to the last question was answered in your own post...the plug is fouling BECAUSE you are not riding it hard.

Break it in the way you feel comfortable, then let her rip!!! These things want to be riden hard.

Have fun with your new toy, and welcome aboard!!

Dennis :)

The 426 has a "waste ignition cycle", which simply means that it fires every time the piston comes up. . . . just like a 2-stroke. Routine changine of the spark plug is probably a good idea. I generally change mine about every 4 races. That includes several practice sessions. I think it makes sense to change the plug BEFORE it starts to affect performance.

Hint: It's a very good practice to blow compressed air through the weep hole on the side of the cylinder before removing the plug. This will blow out accumulated dirt and debris that could fall inside the head when the plug is removed. You will be surprised just how much crud will come flying out. Protect your eyes when doing this.

Originally posted by d_criss:

the plug is fouling BECAUSE you are not riding it hard.

I'm sorry but I disagree. If a bike is jetted correctly, it should NEVER foul a plug. Especially a fourstroke. You should be able to sit and idle for 30 minutes if you wanted to, and not foul a plug. You should never have to ride a bike hard to keep from fouling a plug. If you do...REJET.

If it fouled one plug, and you haven't changed anything...more than likely it will foul another.

BTW, my '01 has stock jetting, no BK mod, no blue wire mod, and has never fouled a plug. I'm roughly at sea level.

[ March 28, 2002: Message edited by: CAL ]

You should not have to ride hard to keep the plug good. I've ridden my '01 with my wife (a beginner on an XR100) and I had no plug problems at all. Needless to say I was just above idle in 1st gear all day (ZZzzzz...). I had plug fouling problems when I used Mobil brand gas. I switched brands and I've had the same plug in ever since (several months now) and it runs like a champ. Another thing that I've found to cause these things to foul plugs is flooding (turning the throttle before you start it, etc..), at least in my experience. But you've learned one thing that took me about 200 kicks to learn. If it won't start relatively easily, change the plug before you do anything else. Have fun with the new toy! :)

hey man

my bike was a big pain and always fouled plugs and now i don't know because i did the blue wire trick and haven't ridden since, so i don't know what good it did. anyways, make sure that you don't over oil the air filter, i did that and became very frustrated when it did not start. i am glad to welcome you to the brotherhood of the yzf.


Itrosson Or ?

try looking here for a pointer on starting the beast

My Wizer starts Hot or cold on the first Kick every time. Follow these steps

and follow the one golden rule

Never never never touch that throttle untill the beast is lite

Golde rulle Number two

Kill Any one that attemps to put there hand on the throttle when its not running


As Motoman points out Look for the Blue Wire Threads and make a desision if its right, Bottom line is alot of people here have had problems with fouled plugs, I think most follow the leads and suggestion of the threads here, We will not stear you wrong, Well Maybe Thumper4life but well advise to read the threads.

Ride the bike as you are able get used to it as stated above, the primary goal is to have fun

[ March 28, 2002: Message edited by: EgoAhole ]

hahaha, not the blue wire! cut the red one! :D thanx for the lil advertisement :D

Make sure you tell him how to relieve his issue with his red header after 4 minutes of idling too....hopefully he's not a dog lover. :)

And remember kiddies! Change that spoke oil! :D

hahahaha, that made my day when i heard that one

One thing to add, if you had this problem with just one plug there is also the chance the plug is bad. Just last week I was doing the maintenance thing and put a new plug in my bike because I hadn't changed in a couple of months. Brand new plug my bike sputtered and spat around the track like my bike was on it's last leg. Put the old plug in and it ran like a top. Went and exchanged the plug and everything was fine. So it is conceivable you just had a bad plug.

I agree about holding off on the mods because BK indicated that the 02's solved most of the problems the mod was designed for. If you do have to resort to jetting you can try tinkering with the Hot start and choke. Hot start = leaning the bike out. Choke = richening the bike up.

Check the air filter. My friend rode his new beast without checking the Filter. Needless to say it was dry. It let some dust in the Carb. After he cleaned the Carb and Filter it started first kick.

This bike is a beast and must be ridden like a beast. She doesn't like to stall because you are too much of a wimp on the throttle. She doesn't like rollers. She likes fast only. She wants someone that can give her a hard kick. If you fail to give it to her hard than she will rather sit than go slow.

oh i give it to her hard! i give it to her hard ALL NIGHT LONG! when it fouls a plug :)

Everyone who has done any research knows the woes of the YZF but the whooos outweigh so here she goes, I bought an 01' after 15 years of riding used bikes (mostly yamahies) and much to my dismay she fouled two plugs the first weekend and wouldn't even run the second. I took the $6k trailer queen back to the dealer immediately and they told me at first that I wasn't riding it hard enough (not true). And thankfully with a four-stroke not much else can be blamed (no-mixing of oil right) so I got the real answer from a guy who worked at the dealership who rode one and he insisted that they could be riden any way you liked. Making a long story short they replaced the carb for something like $1400 (they said) and it runs alot better now, only fouled two recently and once was because I left the gas on. Doing the blue wire thingy tonight though

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