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raptor 250 carb issue

10K views 16 replies 4 participants last post by  setbrew45 
#1 ·
Im in need of help!! i have a raptor 250, just got done replacing starter and cleaning carb twice!! it idles fine but any kinda throttle i try to give it the quad just dies. It has a pipe open air box 170 main jet.
 
#2 ·
What size is the stock main jet, is the 170 much bigger. Try it with the choke on, see if it's better or worse.

WELCOME TO THE FORUM.
 
#4 ·
^^^^ Try this.
Is the 170 main jet a mikuni jet or dynojet? also look at your needle to see if it's adjustable (will have notches in the top side for different clip settings). The stock main is 133.8 size, so 170 seems a bit large to me for just an exhaust and lid removed. You need to check your float level too. Post pics if you can it may help.
 
#3 ·
im working on it for a friend. It already had mods done and was running but it had been sitting for some months. The starter and gear shaft were broken, i repaired them got it to turn over but no start. I took the carb off and found some trash in the inlet screen. Soaked carb and cleaned all jets and cleaned tank. Im def getting a lean issue but not sure why its super clean inside??
 
#5 ·
Pulled carb off for the third time. Not sure what kind of jet it is. Set the float at 13 mm. Itll fire right up and idle like a champ as soon as i hit the throttle it pops spits breaks up and dies........if i spray some gum cutter in the air cleaner while i hit the throttle it will pick up the rpms ....ive never had a quad act this ignorant
 
#7 ·
Make 1/4 turn adjustments each way to your mixture screw. See if that helps. If so, then fine tune it 1/8 turn or less. If not, raise your needle up one notch.
 
#10 ·
Will it stumble when riding, or in neutral sitting still?
What is your idle set at? Can you increase it?
Raise your needle once again.
You may need the next bigger size main jet, and fine tune again.

You need to tune it to find just the correct combination. It takes time, but so rewarding.
 
#12 ·
^^^Need more answers.^^^
 
#13 ·
What comes with the gytr jet kit? 4 mains, 1 pilot and a needle, correct? I had a friend buy one for his kids raptor 250, he said they had a hard time getting it right too.
Did it come with instructions/guidelines to start with?
I did re-jet my daughter's raptor 250 using a dynojet kit, it ran pretty close to the instructions. The main is a 150 dynojet# which is close to a 140 mikuni jet, the needle is on the 2nd or 3rd clip,(can't remember) and mixture screw around 2-2-1/2 out.
Our raptor setup is: Barkers full exhaust, GYTR intake, Uni and gytr filters used, open airbox, dyna ignition, dynojet kit...

I still think you're way big on the main, i didn't think the gytr kit comes with anything larger than a 140 or so...try dropping the needle to the 2nd-3rd clip, also check the diaphram at the top of the carb for tears in the rubber.
 
#14 ·
^^^ The OP said it's better with the choke on. ^^^ So it seams he needs more fuel.

What does the plug look like?
 
#15 ·
Yea if you pull the choke or turn the idle up it makes it easier to accelerate. I can adjust the main later my primary goal is the pilot system. If I try to feather the throttle it spits and pops and eventually dies if I keep accelerating. Its stubborn I've adjusting the fuel screw out 31/2 and does not make a difference. The diaphragm looks good I checked for air leaks.
 
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