Hard to start = how many kicks?


40 replies to this topic
  • guitarnut57

Posted July 17, 2009 - 01:55 PM

#1

How many kicks should it take to start an '04 YZ 450 cold turkey? When the motor is cold and with the choke engaged, it takes about 5-6 kicks to start my YZ. Once the bike gets hot (after 5-7 laps), I am often forced to let the bike cool down for 5 minutes before I can even start it again-even using the hot start. Is this normal for this year model YZ? I have heard both "yes" and "no" from locals.

  • mjw1

Posted July 17, 2009 - 02:15 PM

#2

Yes and no cold it could take that many kicks but warm it should fire back up in one or two kicks, your bike may need to be jetted do you have aftermarket pipe? does it backfire on deceleration? A little backfire on deceration is normal but if it does it alot you might need to turn out your air fuel mixture screw or put a bigger pilot jet in.

  • grayracer513

Posted July 17, 2009 - 03:13 PM

#3

It should start in 4 or less, dead cold. I can usually light up my '06 in one, and my '03 rarely took more than two. It's a matter of learning just what it likes. My '03 always wanted 2-3 squirts, push it through to the first compression stroke, and kick it with a very slightly opened throttle. The '06 likes to be heavily primed.

Hot starts are more complicated and situation sensitive, but follow the same general pattern; if it's freshly stalled or just shut down, use the hot start first. Otherwise try it without it first.

Starting problems are almost always rooted in carb tuning.

  • guitarnut57

Posted July 17, 2009 - 03:37 PM

#4

Yes and no cold it could take that many kicks but warm it should fire back up in one or two kicks, your bike may need to be jetted do you have aftermarket pipe? does it backfire on deceleration? A little backfire on deceration is normal but if it does it alot you might need to turn out your air fuel mixture screw or put a bigger pilot jet in.


Yes, the bike has as an FMF 4.1 slip-on. The bike has never backfired on deceleration; however, from time to time, it does backfire when trying to kick it over if the bike is cold.


It should start in 4 or less, dead cold. I can usually light up my '06 in one, and my '03 rarely took more than two. It's a matter of learning just what it likes. My '03 always wanted 2-3 squirts, push it through to the first compression stroke, and kick it with a very slightly opened throttle. The '06 likes to be heavily primed.

Hot starts are more complicated and situation sensitive, but follow the same general pattern; if it's freshly stalled or just shut down, use the hot start first. Otherwise try it without it first.

Starting problems are almost always rooted in carb tuning.


The previous owner told me to never give it gas when trying to start it, or the bike would flood and be very difficult to start. So I have never tried it. So when the bike is hot and will not start, just give it a little gas like you would when starting a 2t? Experiment and find the sweet spot?

  • joethunder

Posted July 17, 2009 - 06:12 PM

#5

My 04 was rarely more than 3 kicks cold, usually one or two.:worthy: Hot starting was never a problem, unless it was really hot.

One quick squirt, and kick it from tdc.

  • grayracer513

Posted July 17, 2009 - 07:11 PM

#6

The previous owner told me to never give it gas when trying to start it, or the bike would flood and be very difficult to start. So I have never tried it. So when the bike is hot and will not start, just give it a little gas like you would when starting a 2t? Experiment and find the sweet spot?

Kind of.

What you don't want to do is the typical Real Pinger Guy "twist as you kick" thing....ever.

On your cold start, try 2-3 full twists of throttle, then leave it closed and kick with the choke on. If it hasn't hit in two, try one more squirt. If the third doesn't light it open the throttle just off idle, less than 1/8 throttle, and hold it steady as you kick.

Hot starting, you will usually be faced with an engine that has too much fuel rather than too little. This is why the hot start is there. All it does is bleed extra air into the intake. Experiment with using/not using the hot start and no throttle.

Now, let me ask you this; at starting speeds, does opening the throttle a little give you more gas, or less? Think about it. What pulls gas out of the carb? Vacuum. When you open the throttle at cranking speeds it reduces the vacuum available to the pilot jet, and you bring in more air with less gas. So opening the throttle up will clear a flood, not cause one, as long as you remember there's an accelerator pump in there, and don't get too carried away. Opening more than about a quarter will just about eliminate the possibility that it will start, though, and you'll have more luck with around an eighth.

  • guitarnut57

Posted July 17, 2009 - 07:22 PM

#7

Man you have no idea how much I appreciate your help, as this bike has been giving me fits when it gets hot. One good stall or wipe-out after a few hard laps, and your moto is over!

When I go riding tomorrow, I'll try everything you posted above. I'll let you know how it works.

Thanks Everybody

  • saccityfire

Posted July 18, 2009 - 11:30 AM

#8

Seems too rich already if it never backfires during deceleration.

GR, I used to open up my 250F to full throttle if I dumped it while racing and that fired it in 2-3 kicks after which I close the throttle and it starts next kick. I discovered this after playing around with it after I dropped it in one race and the field literally lapped me twice while trying to restart. The open slide lets in a ton of air to lean out the rich condition plus the extra squirt of fuel from the accelerator pump (I think?)

I'm very green though and look to you for advice on this as well.

  • Aka.Goose

Posted July 18, 2009 - 11:58 AM

#9

After putting in a new motor and new pipe, and reusing my previously ZipTy modded carb, my 07 now likes the throttle 1/8 cracked when cold, 2-3 kicks(I was very surprised at this, took a while for me to accept it)...
Once hot, one kick with no gas with hot start in...

  • kain522

Posted July 18, 2009 - 01:56 PM

#10

The cold starting drill on my '04 goes like this: Turn on gas, Pull choke to full, Twist the throttle twice, Kick all the way through from tdc, Listen to engine run. Even after sitting through a Wisconsin winter, it only took 5 kicks to come to life. Hot starting is a different ballgame. Sometimes it wants the hot start, sometimes not. That seems to change with however warm it is that day. It always takes 3-4 kicks when hot, one when cold.

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  • grayracer513

Posted July 18, 2009 - 04:45 PM

#11

GR, I used to open up my 250F to full throttle if I dumped it while racing and that fired it in 2-3 kicks after which I close the throttle and it starts next kick. I discovered this after playing around with it after I dropped it in one race and the field literally lapped me twice while trying to restart. The open slide lets in a ton of air to lean out the rich condition plus the extra squirt of fuel from the accelerator pump (I think?)

It works like that on the 450, too, but all you'll get is a couple of gurgles out of it at big throttle openings. It can't generate enough vacuum to start on, even though it's flooded. Clearing the flood like that is a step in ther right direction, though. Closing the throttle back to around a quarter strikes a balance between the clearing the flooded condition and providing an adequate draw on the fuel circuits to get them started. Experiment.

  • Justin89

Posted July 18, 2009 - 05:16 PM

#12

Could also be time for a valve adjustment...

  • saccityfire

Posted July 18, 2009 - 06:16 PM

#13

It works like that on the 450, too, but all you'll get is a couple of gurgles out of it at big throttle openings. It can't generate enough vacuum to start on, even though it's flooded. Clearing the flood like that is a step in ther right direction, though. Closing the throttle back to around a quarter strikes a balance between the clearing the flooded condition and providing an adequate draw on the fuel circuits to get them started. Experiment.


Thanks GR. That would explain the need to close or at least reduce the throttle before it will run.:worthy:

  • guitarnut57

Posted July 20, 2009 - 04:29 PM

#14

Well, I took the YZ out for a 4 hour run this weekend at the track, and I tried the new starting techniques (squirts of gas here and there). Here is what happened:

Cold start - 4th kick with choke, fired up

20 minutes of hard riding, 15 minute bike cooldown - 1st kick, fired right up

20 minutes of hard riding, but bike stalls - kick, kick, kick, kick, kick, kick and kick again. Nothing. 1/4 squirt, kick, kick, kick, 1/4 squirt, kick, kick, kick, blurbbbbb, kick, kick, kick blurbbbb (ok you get the idea). This went on for about 5 minutes. At times it sounded like it was going to start, but it would fizzle out and die. I eventually let the bike sit and cool down for about 5 more minutes, 1st kick, fired right up. :banana:

I am kind of short (5'8"), but I do my best to get a full kick in. My hot start lever is stuck, so I did not have a chance to see if it would help. I can tell you that it only helped a little in the past.

What am I doing wrong guys? :worthy:

  • yzf426boss

Posted July 20, 2009 - 04:38 PM

#15

i have a 2000 426. i am 124 lbs and this is how mine starts. Cold-choke, no gas, one kick from tdc. hot-hot start, no gas, one kick from tdc. its all about your jetting and knowing your bike!

  • grayracer513

Posted July 20, 2009 - 07:10 PM

#16

My hot start lever is stuck,

You need to fix that.

  • husqy360

Posted July 20, 2009 - 08:48 PM

#17

i start mine first or second kick cold first when its hot. my buddy got a 500 2 t and lol he kicket it like 200 in 1 day.

  • roylo

Posted July 21, 2009 - 01:01 AM

#18

Well, I took the YZ out for a 4 hour run this weekend at the track, and I tried the new starting techniques (squirts of gas here and there). Here is what happened:

Cold start - 4th kick with choke, fired up

20 minutes of hard riding, 15 minute bike cooldown - 1st kick, fired right up

20 minutes of hard riding, but bike stalls - kick, kick, kick, kick, kick, kick and kick again. Nothing. 1/4 squirt, kick, kick, kick, 1/4 squirt, kick, kick, kick, blurbbbbb, kick, kick, kick blurbbbb (ok you get the idea). This went on for about 5 minutes. At times it sounded like it was going to start, but it would fizzle out and die. I eventually let the bike sit and cool down for about 5 more minutes, 1st kick, fired right up. :banana:

I am kind of short (5'8"), but I do my best to get a full kick in. My hot start lever is stuck, so I did not have a chance to see if it would help. I can tell you that it only helped a little in the past.

What am I doing wrong guys? :worthy:



My 450 usually starts first kick when cold or hot. But, every now and then for no apparent reason, and starting in the same way it may take 5 or more kicks.
Ive found after a stall is the hardest to start and can take quite a few kicks sometimes. I find a tree or something to lean on so I can stand right up to kick it, and use the hot start aswell. Make sure you get the piston at the top of the compression stroke with the kick starter then give it a good hard kick each time right through is the best advice I can offer.

  • guitarnut57

Posted July 21, 2009 - 05:49 AM

#19

You need to fix that.


Hopefully, I will be able to fix it this afternoon.


My 450 usually starts first kick when cold or hot. But, every now and then for no apparent reason, and starting in the same way it may take 5 or more kicks.
Ive found after a stall is the hardest to start and can take quite a few kicks sometimes. I find a tree or something to lean on so I can stand right up to kick it, and use the hot start aswell. Make sure you get the piston at the top of the compression stroke with the kick starter then give it a good hard kick each time right through is the best advice I can offer.


Get the piston at the top of the compression stroke? Forgive me of my ignorance, but how do you know when the piston is at the top of the compression stroke?

  • kain522

Posted July 21, 2009 - 05:54 AM

#20

Hopefully, I will be able to fix it this afternoon.




Get the piston at the top of the compression stroke? Forgive me of my ignorance, but how do you know when the piston is at the top of the compression stroke?


You will feel it. Push the kicker over slowly, and when it comes up on the compression stroke, you will feel resistance. If you don't, there are other issues that need to be resolved.





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