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1998 yz400f carb ?

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bike is hard to start cold but when warm starts 1 kick , runs LIKE THERES NO END just wont start cold kick kick kick , also ve had bike since new put a big gun header and tail pipe two weeks after got it never jetted or messed with fuel screw always ran very good to me but i just broke it out after sitting 8 years took carb all way aprt two times new plug new aif filter race gas never ran pump threw it always 104 octain ive screw in fuel screw it idles down screw it out to about 2 1/2 or so idles smooth a bit if i crack it but dont miss a lick no super red pipe never have opened head ever always hard cold start any help here?

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also no air leaks spayed car cleaner all aroun does nothing putting fuel screw in or out dont help cold start 

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Okay,change your pilot jets, its almost impossible to clean them, especially if its been sitting for so long. I also think your bike is supposed to run on about 94 octane pump. that race gas won't do you no good. You would need one of em high compression pistons for you to get good use out of it.

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ok thanks so pilot will stop hot start knob from making idle rise when pulled

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No the hot start knob won't be affected. Like koolaid said, you should check the valve clearances and redo the whole carb, seals gaskets, needle/seat, float, jets. Everything should be serviced.

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so when everything is set right pulling out the hot start at idle will make idle rise??

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Nope, hot start shouldn't make your idle rise much, it just let's cold air in so it's easier to star when hot.

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so when everything is set right pulling out the hot start at idle will make idle rise??

 

Yes, it will make the idle rise, if the motor is cold, and maybe a little if hot

 

It adds air.

 

Don't focus on this, it's not important

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ok my freind i went out  this morning tryed the hit throtle 3 times deal with choke on fired up died did same three times idles good with choke on turned choke off idle drops nice now everything is sweet 3 turn out on fuel all is good but is it posable that i still need valves checked everthing runs great but yet i bought bike new never had any issues the one i just had was card couse bike sat 8 years never fired nothing i no if not broke dont fix just would like input on no valve work since it was new valve cover never off i have always ran moble 15/50 evry 15 hours was changed always ran nutten but race gas i just cant get over never no issues with valves or anything knock on wood!! and bike sitting that long no seals are leaking nothing its just unreal bro!!

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everything on bike is stock never did fork seals nothing change oil ad gas and go just added a big gun pipe a month after i had it header and tale never messed with carb after install it might be alittle lean but not back fires on rev up or decell maybe im missing some power if did need bigger jets IDN nothing about carbs but i did half to take apart first time this week and cleaned very good works well how would i no if did need more fuel couse of pipe i had put  on in 98 omg this bike is old lol but runs as well as when i rolled off showroom floor

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i no i need new fuel oring it is flatend on one side pretty good but is working for now lol i guess i just got realy realy lucky on this bike

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Hey, if it's running that's all that matters. Have fun with er and be safe! :ride:

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Just seems not right I hear all these other bikes halfting to do there valves maybe mine do need it alls I no is it screams like first day on it

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ok guys u have been great HELP here THANK U! one more thing here fuel screw is 3 out for best idle is that cool? and only on a cold start bike pops until its warm not hot when warm stops popping but again thing RUNS GREAT just popping at first COLD start. THANKS GUYS U HELP SO MANY PEEPS MY PROPS!!! OUT TO YA!!!!!!!!!!!


OH just to state EVERYTHING is STOCK inside carb 

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No worries broskii, that's what this sure is for. Three turns out is petty good, it should normally be at 2 and a half but 3 is alright too. The popping to me seems like a valve clearance issue. Does it pop under decel?

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