Pulled the choke bike wont start

the chock must be bad.
on all carb cars , since 1964 i remove it and make it a manual choke
then hot starts are easy, hot, its not touched. (instant starts hot)

chokes this old never work right, they are TOO old
the spring in side (bimetal) is NO GOOD. it fails to open properly.
try setting the choke calibration more lean.
if at higher altitude, even leaner.

the book is free. see it here
http://www.fixkick.com/sammi-stuff/index.html

The choke is a device on most old carbs (varies by country)
that closes a butterfly valve, (google that) and starves the engine of air, thus the word "CHOKE" as in Choking it.
this causes higher venturi vacuum and more fuel flows from the jet nozzles.
if the chock is set too rich the engine floods
if set too lean , you have to pump the gas pedal to keep it alive.
if the bimetal spring is slow, it floods
if the choke is electic the heater needs to work or the choke sticks on.
if the choke is water heated, the water needs to flow there. again
the motor floods and stalls.

rtm. read the chapter on the Choke, the book is free.
http://www.fixkick.com/sammi-stuff/index.html

minha yz426f quando vou de terceira marcha devagar mas quando eu acelero a fundo ela engasga , mas ? so de terceira marcha de rewsto nao faz isso

try pulling the choke when you start with a little gas, if i remember right the NSR has a carb & choke right?

Is this a new saw? If yes return it or at least ask for a recommended repair facility. Your saw is actually a Dolmar (owned by Makita) and a fine saw. In order to meet EPA requirements they are set very lean (many 5100s seize with factory settings). To protect your investment and not invalidate your warranty I recommend it be adjusted by the
professional recommended by the merchant where you purchased it or one recommended by Makita.
The starting procedure is probably similar to this:
Start Procedure
Cold:

1. Ignition on/off to on.
2. Set compression release – optional step even if saw is equipped with a compression release.
3. Pull (close) choke, set fast idle (done when choke closed on some saws); pull starter and listen for an attempt to start. once heard (usually two pulls; no more than 4).
4. Set compression release – optional step even if saw is equipped with a compression release.
5. Push (open) choke pull starter until it starts. (usually first pull).

Warm:

1. Ignition on/off to on.
2. Set compression release – optional step even if saw is equipped with a compression release.
3. Pull (close) choke, set fast idle (done when choke closed on some saws) – Do not pull with choke closed.
4. Push (open) choke, pull starter until it starts. (usually first pull).

Most new owners miss opening the choke after it tries to start or do not hear the pop when it does and flood the saw.

If you have more questions or need additional help please reply below and I will get back to you. Thank you for using FixYa and Good Luck. HTH
Lou

Start at 1.5 CCW form lightly seated then tune for performance like this:
Carburetor Adjustment by Madsens.com
http://www.madsens1.com/saw%20carb%20tune.htm
CW is leaner; to lean will destroy the saw. If over tightened closed (CW) the adjustment screw faces are easily marred; marred adjustments are difficult to impossible to set properly.
Clean the air filter; adjusting with a dirty filter can cause a run lean condition once cleaned and the saw run.
There are 2 wav (sound - idle & full – may not be highlighted) files that I find most helpful, I think you will too.

I think your starting procedure may be the cause of flooding. Flooded is the #1 cause of hard starts in 2-cycle engines. Read carefully the recommended start in your manual. most miss the second note. It should be similar to this (read 3, read it again):
Warm start in the manual says 1/2 choke BS. Close choke, (sets fast idle) open choke, pull rope.
Start Procedure
Cold:

1. Ignition on/off to on
2. Set compression release – optional step even if saw is equipped with a compression release
3. Pull (close) choke, set fast idle (done when choke closed on some saws); pull starter and listen for an attempt to start. once heard (usually two pulls; no more than 4).
4. Set compression release – optional step even if saw is equipped with a compression release.
5. Push (open) choke pull starter until it starts (usually first pull).

Warm:

1. Ignition on/off to on
2. Set compression release – optional step even if saw is equipped with a compression release
3. Pull (close) choke, set fast idle (done when choke closed on some saws) – Do not pull with choke closed.
4. Push (open) choke, pull starter until it starts (usually first pull).

If you still have trouble reply as you did before. I will get back to you. HTH
Lou

I am going to assume you are following the warm start procedure in your manual. Most start problems with 2-cycle engines are caused by flooding.

Before you shut if off roll it to the side and loosen the fuel cap (vent tank - leave it loose until restart) Better? Repair fuel vent. No better carburetor needs small adjustment. This explains it better than I can but you will need to experiment some.
Carburetor Adjustment by Madsens.com
http://www.madsens1.com/saw%20carb%20tune.htm
CW is leaner; to lean will destroy the saw. If over tightened closed (CW) the adjustment screw faces are easily marred; marred adjustments are difficult to impossible to set properly.
Clean the air filter; adjusting with a dirty filter can cause a run lean condition once cleaned and the saw run.
There are 2 wav (sound - idle & full – may not be highlighted) files that I find most helpful, I think you will too.

Just because this is the most likely cause:
Start Procedure
Cold:

1. Ignition on/off to on
2. Set compression release – optional step even if saw is equipped with a compression release
3. Pull (close) choke, set fast idle (done when choke closed on some saws); pull starter and listen for an attempt to start. once heard (usually two pulls; no more than 4)
4. Set compression release – optional step even if saw is equipped with a compression release
5. Push (open) choke pull starter until it starts. (usually first pull)

Warm:

1. Ignition on/off to on
2. Set compression release – optional step even if saw is equipped with a compression release
3. Pull (close) choke, set fast idle (done when choke closed on some saws) – Do not pull with choke closed.
4. Push (open) choke, pull starter until it starts. (usually first pull)

I hope you found this helpful. You can reply below if you need additional help.
Lou

It is unusual for a trimmer to flood itself. It is common to have a lean condition diagnosed as rich.
So lets start by seeing if its lean or rich. Get unit running and apply as much throttle as possible and keep unit running then slowly close the choke. If unit starts to run better as choke is closed then it is lean. If unit dies immediately and is hard to start again it may be flooded.
4 possible reasons for flooding...
1. piece of debris in inlet needle, needle lever adjusted too high
2. adjustment screwd turned too far out
3. exhaust screen clogged
4. low compression
If unit has a stuck inlet needle it will flood while engine is off and be very difficult to start- remove fuel source and/or turn adjustment screws all the way in and pull rope until unit starts ( 4 or 5 times)
clean the carb, screws should start at 1 and 1/2 turns out on the low and 1 turn out on the high.
clean the screen.
If the unit has low compression it is not worth repairing- the cost of repair will exceed the cost of replacement.

With the battery charged fully. And the fuel turned on pull the choke out and try starting and one it does push the choke back in so you don't flood the engine.

I think you are saying it sputters but won't run. Once it attempts to fire open the choke or it may flood. My 359 start:
Cold: pull out choke control, pull starter (usually twice) while listening for attempt to start. Once it fires push choke control in and
continue pulling (usually once more).
Warm: pull out choke control (sets fast idle), push choke control in, pull starter.
Page 19 of my manual.
Lou
Once flooded these are a bear to start.

colder plug for NGK. Should I stay with that plug or go with a hotter plug ? That's really ... weird. You have to use the choke ... which indicates you went lean The old exhaust needed no choke shich indicates rich... But you went back to stock which should, by normal standards, make the bike run RICHER if the jet sizes were increased,,,