02 crf450r starts up fine.... let choke off then

nice engine get rid of the choke all together you dont need it its just to choke the engine for cold starting i would get a 725 cfm without choke for it or turn it over to injection tbi or port. do you have an electric fuel pump you will want one when doing without the choke

First- turn on the gas. wait for it to get to the carb. Next switch on- close the choke, give 1/4 throttle, Kick it - if it's a no start after about 4 kicks - open the choke and give 1/2 throttle and close the gas.(your flooded)- 4 more kicks and check the spark plug for wet fuel or dry. If dry- dip the business of the plug in fuel and try again. Still no start- replace the plug.

If all that fails- you can disconnect the ignition switch and that will separate the wiring from the ignition- be careful here because you can not shut it off with the switch it can be killed with the choke or pull off the ignition wire to the spark plug.

Still no start, do a compression test as it needs at least 80# to fire.

Standard starting procedure for YZ400/426/450 is as follows: Push the engine around using the kick starter until you hit the compression stroke. The kick starter will get impossibly hard to push at this point. Now pull in the decomp lever and push the kick starter down a fraction, and I mean a FRACTION. This is where most people go wrong, they push it down too far with the decomp lever pulled in. Now give it a full kick without throttle and it should start.

The above should work fine for a motor that's already warm and was NOT stalled. If the motor stalls it will usually need the hot start button opened as well to let extra air in and bleed out the fuel that usually gets stuck in the motor when it stalls.

For cold starts, you will need to put the choke on, and if it's really cold you might need to prime the engine with a twist of throttle to get the accelerator pump to shoot some fuel in before you start.

As a general rule, NEVER twist the throttle while kicking when you are actually attempting to start the bike, it won't help at all. Also, having your idle screw adjusted correctly makes all of this a lot more easier. Standard setting is usually 1.5 turns out but it should be set to give the smoothest idle you can get using the minimum number of turns out from all the way in. If you have to wind your screw right out to get a good idle you need a bigger pilot jet. Conversely if you have to wind it most of the way in (less than 1 turn) you need a smaller pilot jet. I'm not sure about the 450 but my YZ426 came standard with a 42 pilot jet and changing to a 45 made it idle and start MUCH better. Incidentally the WR model uses a 48.

How to use your choke correctly. The choke is only to be used for starting a cold engine. If it is a lever, usually you pull it up for on , and push it down for off. look for some type off arrow, or up & down. To start your cold engine, turn on fuel tap, give full choke, turn key on and press starter or kick start, it is very important that you do not use the throttle while starting with the choke, just turn the key on, and press the starter with full ckoke, and no throttle. Once the bike fires and starts, turn down the choke a little and find a idle, after a few minits, you can turn off the choke and ride off. The use off the choke is only for starting a cold engine.

first drain the carby, then set your air mixture screw 2 turns out, from the fully turned in position. The starting proceedure is as follows, when the engine is COLD, turn on fuel, pull on the choke fully, and kick the engine over. DO NOT use any throttle, when the engine is cold, and the choke is on. Remember Choke on, NO throttle.
When warm, no choke, and a little throttle when kicking.

Hi
This sounds like a cold start system fault, which is a number of things.

1. Cold start temperature sensor not operating correctly so the cold start system won't work when the engine is cold.
2. The idle needs to be set to the correct RPM of the engine when warm, if it is idling ok when it is warm then this wont be the problem.
3. Spark Plugs are worn and need replacing.

Most case's its the cold start system not operating correctly and if you have a good workshop to take it too they should pick this up quite quickly. Hope this helps, let me know how you get on.

There is a proper way to start the engine. Four controls are on your bike to assist in starting. Below are generic instructions.

• The choke, used when the engine is cold. Pull the red knob for choke.
• The " Hot Start " Lever, used when the engine is hot. Pull the lever to lean the fuel mix when the engine has been running.
• The de-compression lever, always used.
• The throttle, used to prime the cylinder, (power valve).

Don't kick, instead, push the kick lever downward. You will feel the back pressure as the piston is going upward on the compression stroke to the point the pressure is great enough that the kick lever "locks up". You are very close to TDC. NOW, pull in the de-compression lever. Push the kick lever a little bit more to get the piston past TDC. Now release the de-compression lever. Give the throttle a 1/4 turn then let it snap closed. A diaphragm, (Power valve), in the carb gives a shot of gas when this is done. DO NOT do this multiple times because you will flood the engine. Leave the throttle closed when kicking. A flooded engine will often backfire. Now give a strong kick through the full sweep of the kick start lever. Quickly get your foot off the kick lever at the end of the kick to avoid any chance of "kickback" from the kick lever. This happens in the case of a misfire, aka > backfire. It can be very painful, and can even break a leg. I am serious about that. Repeat the process (but without the throttle priming), for six kicks. After six kicks go ahead and twist the throttle again for a second priming. A good battery, a clean spark plug, a clean carb and clean air filter will also aid in starting. Note that not all carbs have a power valve. When a power valve is not present you should crack the throttle open only 1/8 inch from closed on each kick.

There is a proper way to start the engine. Four controls are on your bike to assist in starting. Below are generic instructions.

• The choke, used when the engine is cold. Pull the red knob for choke.
• The " Hot Start " Lever, used when the engine is hot. Pull the lever to lean the fuel mix when the engine has been running.
• The de-compression lever, always used.
• The throttle, used to prime the cylinder.

Don't kick, instead, push the kick lever downward. You will feel the back pressure as the piston is going upward on the compression stroke to the point the pressure is great enough that the kick lever "locks up". You are very close to TDC. NOW, pull in the de-compression lever. Push the kick lever a little bit more to get the piston past TDC. Now release the de-compression lever. Give the throttle a 1/4 turn then let it snap closed. A diaphragm in the carb gives a shot of gas when this is done. DO NOT do this multiple times because you will flood the engine. Leave the throttle closed when kicking. A flooded engine will often backfire. Now give a strong kick through the full sweep of the kick start lever. Quickly get your foot off the kick lever at the end of the kick to avoid any chance of "kickback" from the kick lever. This happens in the case of a misfire, aka > backfire. It can be very painful, and can even break a leg. I am serious about that. Repeat the process (but without the throttle priming), for six kicks. After six kicks go ahead and twist the throttle again for a second priming. A good battery, a clean spark plug, a clean carb and clean air filter will also aid in starting.

There is a proper way to start an engine. Most bikes have four controls to assist in starting.

• The choke, used when the engine is cold. Pull the red knob for choke.
• The " Hot Start " Lever, used when the engine is hot. Pull the lever to lean the fuel mix when the engine has been running.
• The de-compression lever, always used.
• The throttle, used to prime the cylinder.

Don't kick, instead, push the kick lever downward. You will feel the back pressure as the piston is going upward on the compression stroke to the point the pressure is great enough that the kick lever "locks up". You are very close to TDC. NOW, pull in the de-compression lever. Push the kick lever a little bit more to get the piston past TDC. Now release the de-compression lever. Give the throttle a 1/4 turn then let it snap closed. A diaphragm in the carb gives a shot of gas when this is done. DO NOT do this multiple times because you will flood the engine. Leave the throttle closed when kicking. A flooded engine will often backfire. Now give a strong kick through the full sweep of the kick start lever. Quickly get your foot off the kick lever at the end of the kick to avoid any chance of "kickback" from the kick lever. This happens in the case of a misfire, aka > backfire. It can be very painful, and can even break a leg. I am serious about that. Repeat the process (but without the throttle priming), until the bike starts. Go ahead and give it another primer shot after the 5th kick attempt. A good battery, a clean spark plug, a clean carb and clean air filter will also aid in starting.

It usually wont idle very well when it's cold, Goto #1 on the choke give the rope a couple of "quick" tugs, and then move it to #2 Give it one or 2 more tugs with a little throttle, now it should be running witha little throttle, let it run like that for a minute then move it to #3 kinda still pumping the throttle a little and it should take off fine. If this is the 4 stroke, mine did the same thing until it was broke in good. (About 4-5 uses), now I have to say its more reliable than any 2-stroke I've owned and I use it commercially. 1st or 2nd pull everytime and is ready as soon as it fires! Hope this helps!