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Can warm start only using choke !!!! Help !!!!

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New with 05 WR450F (2 weeks).

My WR starts cold after 5 tries (back-fire), but after its warmed up (several miles of riding) it doesn´t start again even using the "warm knob", it back-fire a lot. The only way to start it up again is using the choke. :)

Also on 1st low it doesn't work smooth, it accelerates & decelarates alone.

On 3rd,4th & 5th its a rocket but also with a lot of backfire (gun-machine).

Its incredible how fast it is compared with my old '99 YZ400F.

Did all the free mods:

- Throttle stop cutting

- Baffle removal

- Snorkel out & holes in air box

- Grey Wire

- AIS out

- Jets stock

What can I do? :D

Marco

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Put the baffle back in, and turn the air screw out for more gas. The removal of the baffle makes it backfire. It might be getting too much air in, so try to get more fuel in the CARB. Let me know if it works.

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OK, but to increase fuel on Carb, wich screw do I have to turn out, Air or Fuel Screw ?

Can I turn out the screw without removing Carb ?

Changing PJ from #45 to #48 would help ?

Thank you

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Sounds way too lean-Put in a 72 starter jet, 48 pilot & 40 leak. I recommend the JD jetting kit w/ a 170 or 175 main. Leave the baffle out & jet your bike :)

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OK, cause I'm new in Re-Jetting have some questions.

- Can I change Jets without removing Carb ?

- Are the Air & Fuel screws close to the Jets ?

Thank you

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OK, cause I'm new in Re-Jetting have some questions.

- Can I change Jets without removing Carb ?

- Are the Air & Fuel screws close to the Jets ?

Thank you

The air/fuel screw is on the bottom of your carb underneath a little metal disc. You have to pop out the disc to get to the screw. It is better to put in an adjustable screw. U can buy the Zip ty fuel screw right her on Thumpertalk. U can also jet the carb without pulling it off. Takes a little time to position the carb and I find it easier to loosen the subframe and pull the intake boot off to help the carb twist. Your main, pilot and leak jet are all in the bottom of your carb-change the needle from the top. Happy Jetting!!

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i know i was told not to give it gas when using the e-start, but when its warm, i give it a 1/4 throttle and hit the e-start and it starts up everytime...might wanna give that a try with ur warm starts...p.s. i do the same thing when its cold and it works on the 2nd or 3rd try, im to lazy for the kickstart.

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Well, the future looks better for me now with all your advice.

I have learnt a lot in just one week.

You are very considerated.

I´m thankful.

Now....hands on again.

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OK, cause I'm new in Re-Jetting have some questions.

- Can I change Jets without removing Carb ?

- Are the Air & Fuel screws close to the Jets ?

Thank you

You DON'T have an AIR screw....you need to rejet as mentioned above.

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Well, the future looks better for me now with all your advice.

I have learnt a lot in just one week.

You are very considerated.

I´m thankful.

Now....hands on again.

Go to www.thumperfaq.com. All your questions should be answered with this website. :)

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Changed PJ #45 to #48 and MJ #165 to #170 ---> NO MORE BACKFIRE :D:D

Still having problem with WARM STARTING. :)

Could help changing Starter Jet ? Where is that jet ?

Moving Fuel Screw seems too dificult. :)

In the Owners Manual what name they give to the Fuel Screw ?

Thank you

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i have to give my 05 wr a little turn of the throttle and hold in then hit the e button and starts every time also it popped a little in the cold weather now that it is warmer no problems

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My "Warm Starting" problem IS ALREADY SOLVED. :worthy::D

Gave 1/2 more turn out to the fuel screw and things are really good.

Also "no more backfire". :):D

Overall, what I did in my brand new '05 WR450F was:

- Throttle Stop cut.

- AIS off.

- Grey Wire.

- Silencer Baffle off.

- Snorkel off & two holes to the air box.

- Pilot Jet: #45 ---> #48

- Main Jet: #165 ---> #170

- Fuel Screw: 1/2 aditional turn out from stock position ¿?.

Now my only problem is a "off idle bog". :) (Leak Jet ?)

Also don´t know if the stock position of the neddle is ok for my riding conditions (0-2000 feets, 60-70 deg) ??? :D

Many Thanks to all of you.

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The stock needle is not adjustable. Get an '04 WR needle or a YZ needle. Start with a 35 or 40 Leak jet to help with the bog. If that doesn't eliminate it totally, you can try soldering your stock leak jet closed...SC

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Change the leak jet first. If it runs fine after that, leave it alone. If not, report back.

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