Sputtering at mid to high RPM

[2000]

my 2000 warrior sputters at mid to high rpm. I have a k&n air filter and an fmf power core 4 with a power bomb header. It has a 42.5 pilot jet and the air screw is 1.5 turns out. And a 136 dinojet main jet. The plug is black so I cleaned it and put it back in and ran it 5 minutes and it was black again. So I bought a 45 pilot jet and a 150, 152.5 and a 155 jet to try since dinojet uses different numbers. I know the 45 jet won't help but I wanted to see if it added power. I haven't installed the 45 jet yet. I also did the valve stem cap mod and bic pen spring mod and it was still like this before i did it so it wouldn't be that. I tried the 150 main jet and it still did the same but the plug looked a bit better. I also tried it with out the air box lid and no difference with the 150 main so I will try the 155 just to see. What could be the issue??

 

[Warrior1996]

If the plug is black then you're running rich. You need to get smaller jets, not bigger ones.

 

[hashish420]

mine was doing this run it abit and shut it off check if your vents are leaking the damn ethonal in gas is reecking havock on carbs these days.i cleaned and re adjusted mine like 30 times yet same problem.put in a carb kit and problem solved.also the valve stem cap made mine boggy.

 

[2000]

If the plug is black then you're running rich. You need to get smaller jets, not bigger ones.

Yeah I know but the dyno jets are different numbers so I ordered the common ones I read people use.

 

[2000]

mine was doing this run it abit and shut it off check if your vents are leaking the damn ethonal in gas is reecking havock on carbs these days.i cleaned and re adjusted mine like 30 times yet same problem.put in a carb kit and problem solved.also the valve stem cap made mine boggy.

Great idea I will try that

 

[YAMAHAULER]

the air screw should be 2 turns out

 

[2000]

the air screw should be 2 turns out

Tried that.... What jets do you have in yours? The 150 I had was almost there just a bit black with a bit of tan. So I should probably do a 147.5 ? To me that sounds a bit small with a k&n air filter and power core 4 exhaust with a powerbomb header?hno:

I may just get a zoom zoom carb and jet that :argh:

Thanks for the advice

 

[YAMAHAULER]

I'm running a 07 YFZ 450 FCR carb

 

[YAMAHAULER]

I would try the 147.5 but if the 150 was just a hair rich it's better to be a tad rich than lean

 

[2000]

I would try the 147.5 but if the 150 was just a hair rich it's better to be a tad rich than lean

but it still cut out at over 1/3 throttle. it will accelerate fine but if you keep it at a set rpm it will sputter

 

[2000]

but it still cut out at over 1/3 throttle. it will accelerate fine but if you keep it at a set rpm it will sputter

So a 147.5 may do the trick? should I mess with the needle position?

 

[YAMAHAULER]

You can try adjusting the needle clip 3rd notch down from top is stock moving the clip down richens it and moving clip up leans it

 

[YAMAHAULER]

If it was close with the 150 put the needle clip up 1 notch at a time and see if it leans it out the little bit it needs

 

[2000]

If it was close with the 150 put the needle clip up 1 notch at a time and see if it leans it out the little bit it needs

Ok do you know how to do the needle? I looked in the tutorials but found nothing?

 

[YAMAHAULER]

The plate on top of carb with the 3 screws in it remove and you'll see the slide and there is a white plastic piece with an arm hooked to it with 2 little screws holding it to the slide remove those 2 screws and pull the plastic piece and the needle is under there it will fall out if you tip carb upside down

 

[2000]

The plate on top of carb with the 3 screws in it remove and you'll see the slide and there is a white plastic piece with an arm hooked to it with 2 little screws holding it to the slide remove those 2 screws and pull the plastic piece and the needle is under there it will fall out if you tip carb upside down

Ok thanks i will try that tommorow thanks for all the help!

 

[2000]

Ok so I tried a 155 main and a 45 pilot and it was much worse. so next I will try a 147.5 and go back to a 42.5 pilot. Does this sound like the right track?

I also bought a zoom zoom carb to try

 

[YAMAHAULER]

If its rich then yeah going with a smaller jet will lean it out you just gotta figure out what size jets will get you close

 

[YAMAHAULER]

Did it idle good with the 45 pilot?

 

[2000]

Did it idle good with the 45 pilot?

It idled fine just was a bit hesitant below 1/4 throttle and I just tried the 155 to see what would happen.