Oil change killed my bike!

Derek & dog,

Just a note. All bikes have their quirks. I ride with a group of guys and there are 3 426's amongst us. No two of them are the same regarding starting. Mine floods occasionally. It has been jetted and set up by the YZF guru hisself Doug Dubach. He says that flooding can be the nature of the beast. It runs awesome but I had to learn what to do and what not to do. I always turn my gas off before stopping the motor. Even when taking a quick break. When the motor stops unexpectedly (read fall) then some times it will start right away and some times it won't. I know by the 4th kick. I took a 17mm wrench, cut off the open end and had a holster sewn in my boot to hold it. Takes me just a few secs to whip out the wrench, drain the bowl and be on my way. Just my dos pesos.

I agree with Klokard, I always turn off my fuel and even let it run for a moment before killing it. It has alleviated any of my starting difficulties. I am on the same plug for over a year. Also what size pilot did they install?, what kind of fuel are you running? and have you adjusted your fuel screw? :cry:

First off, thanks everyone for your input! I'm getting back into riding after quite a few years off, so the whole experience is a learning process again! I'm glad I found this site, the sheer wealth of knowledge is amazing!

Klokard: Excellent point...and good to know. Now, excuse my inexperience, but what do you mean by "drain the bowl"? Sounds like an excellent idea.

Fastest1: My new habit is gas first, then kill. Can't hurt, right? The shop put back the stock .43, but said it would run rich since it was "worked on" by the previous owner. They didn't think it would be enough to give it any problems or foul the plug, but I am going to check it anyway since it has about an hour total on the new plug, so I would like to see what it looks like. I've been running highest octane I can get from the pump, and no, haven't adjusted the fuel screw.

Start by turning in the fuel screw in 1/4 increments, there is no need to be rich anywhere. If adjusting your fuel screw doenst change anything you might have to change your pilot. These things change with altitude, heat and humidity so you might as well learn how to do it. There are so many pages here to help it isnt funny. Buy a Kouba or other extended fuel screw. It makes it adjustable while you are sitting on the bike with no tools. Listen for a slight popping on decel after she is warmed up. :cry:

BTW I also have this belief that the choke should only be needed if it is cold (once a day at most) and the hotstart should be needed if it is hot, otherwise adjustments are wrong. :cry:

Jetting sounds like the answer. AS was said above it could just be a fuel screw adjustment. If not you may have to dig into the jets.


On the very bottom of your carb is a 17mm cap bolt that you remove to drain the fuel. When my bike floods after a fall, draining the bowl is the ONLY way it will start. This should also always be done when putting the scoot away for any extended period. If there is fuel left in the carb it can turn bad and create havoc with your jets and passageways. Some people allow their bikes to idle and burn the gas but these things can get kind of toasty sitting around idleing.

Rockindog, I agree with you- this site and the folks on it kick-ass and really help us newbies. I had inconsistent results starting my 426 until I did some searching on tt...it was like BAM! I got it...maybe this can help with your starting issues as well...the yamaha video was icing on the cake: http://www.thumpertalk.com/forum/showflat.php?Cat=0&Board=UBB6&Number=958953&Forum=UBB6&Words=the%20drill&Match=Entire%20Phrase&Searchpage=1&Limit=25&Old=allposts&Main=957923&Search=true#Post958953 good luck :cry:

Hey Rockindog,

The original owner of my 2001 YZF426 told me to follow this procedure on cold start up.

1. Turn the fuel on

2. Pull choke out

3. Pull in decompression lever

4. Kick the bike three times with lever in

5. Release lever and get the bike to the hard spot

6. Pull compression lever in and go slightly past that hard spot, then allow the kick starter to return to the top.

7. Release decompression lever and kick the bike

8. Keep hand off the throttle

Repeat steps 5-8 if it doesn't start the first time.

When mine is hot, I used the hot start generally. After 2-5 minutes of sitting off, I will not use the hot start.

BTW.. I am located at 95th and Beardsley. We go riding alot with a pretty good crew. All 4 strokers right now too! :cry:

Email me at greg@emotoman.com sometime......... give me your email and I will put you in the loop for future rides too.

Good luck with the starting demons. One thing I learned from buying this bike used is..... take nothing for granted. I thought since he had put a Yoshi Ti pipe on my bike that it was re-jetted. NOPE Now I know why it was running hot in lower elevation and running like a rapped ape in the high country.

PLUGS GO BAD whenever they feel like it......I always keep 1-2 with me on the trail.

Glad to here AES Motorsports seems to be a decent place to do business. I have been sending all my business to Screwie Lewies since I got my bike. Rode with Justin, who works up there. Deer Valley and 25th ave.

Good luck! Hope to hear from ya! We are doing and 80-100 mile ride tomorrow if you got the bugs worked out!

Found this off of Yamaha site:



Make sure the bike has fuel, then turn on fuel petcock.


Pull out choke knob (black knob on left side of the carburetor).


Prime the engine by giving the throttle two full turns (only if the bike has not been started in a day or two).


Apply firm pressure to the kick-starter with your foot until you hit distinct resistance (this is the compression stroke/hard spot).


While keeping pressure on the kick-starter, pull in the compression release lever and push the kick-starter past the compression stroke/hard spot. The kick-starter needs to only move about 1 to 2 inches past the hard spot. That is all!


Release the compression release lever and return the kick-starter to the top


Now, kick to start. Do not touch the throttle, as the engine will start and idle on it's own


If the bike does not start, repeat steps 4 through 7 only until the engine starts.



Pull out the hot start knob (red knob on the left side of the carburetor).


Follow steps 4 through 7 until engine starts.


You may have to apply some throttle after the engine starts until you get the hot start knob pushed back in because the carburetor is sending a lean mixture while the hot start knob is out.

The only difference between hot and cold starting is which knob you use, choke or hot start. There is no need to deviate from these simple steps. Remember, DO NOT touch the throttle during hot or cold starting. Also, there is no reason to prime the engine again on the same day of riding.


It helps to become comfortable with steps 4 through 7. By becoming familiar with these steps you will become more efficient and will be able to perform them quicker. The faster you can get through steps 4 through 7 the quicker you will get going.

You need to give the engine what it wants! Understand that the choke will give the engine a rich mixture and the hot start will give the engine a lean mixture. If you have kicked the engine several times during a cold starting procedure and it still won't start, maybe it has too much fuel. Don't be afraid to push the choke back in and use the hot start, even though the engine is cold, this will give the engine a lean mixture and that might be just what it wants.

Again, make sure you don't go more than an inch or two past the hard spot when setting up your kick, and return the kick tarter all the way to the top, especially on the 250F. This will ensure that you get a proper kick and make your race day more enjoyable.


yesterday i took it to a shop on 83rd & union hills. it is called AEO powersports". "this guy does a lot of MX prep work out at some of the tracks. the guys name in the back is Jamie... from first impression he seemed to know his stuff.

Just to let you guys know there is another mechanic in that shop named Bob Blose, Im sure all of you guys have heard of Chris Blose, well this is father and he definetely knows what he is doing. HAHA look at his kid! Anyways i know all the people at AEO and they are great people, plus they help me out by sponsoring me so I would definetely recommend their shop over any other shop like metro or YSA. Oh and for future reference both YSA and Metro are owned by the same owner :cry: anyways its 4:20 on friday Time to hit up the track lata guys!

-MotoX #352 <---- look for me out at the track @ Canyon Raceway. Thats my real number btw!

The guys up at Carefree Yamaha are really good to work with. They're in the same chain as Extreme in Scottsdale and Apache in Phoenix. I'm pretty convinced that Metro is only good for picking up a quart of oil, and that's only because it's closest to me. I've been by AEO, but never been in. I'll have to stop by there too.

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