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Running rich?

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So last weekend i put a new vertex piston in my yz269f along with a stage I intake cam (stock exhaust), new cam chain, went through carb which the ap bowl was rough. Guess when i drained the bowl and ran it out best i could it didnt all come out of there last fall. Cleaned that problem tho. Checked valves after assembly, ap squirt before i put carb back on etc.

So i got bike together fine and it runs but not as well as it should be. I currently have a jd jet kit and running a 40pj. Weather has been 80s and humid. Bike doesnt start with choke ON, it actually seemed to be getting flooded as i smelled gas after a number of kicks with it on. Once started n running however it was decel popping quite a bit. Then it also feels kind of boggy up to about quarter throttle and hesistates to where it make acceleration not smooth. I just find it hard to believe a 40pj is too rich. Does it seem rich though?

Just seems like a weird combination of things so I wasnt 100% sure where to start.

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Check to see that your hot start (cable)plunger is working properly. Mine gave me trouble couple times on that bike.

42pj was spot on  for my built 269.

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48 minutes ago, J_YZ2fittyF said:

Ill check that. Just seems itd WANT choke if hot start was stuck open upon cold start. It starts without choke! With it on as i said it seemed to flood.

I'd bet you didn't check float height and you have an aluminum fuel screw. Float height may be high.  If you have aluminum fuel screw, replace it with a brass one.

 

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1 hour ago, ronbuell said:

I'd bet you didn't check float height and you have an aluminum fuel screw. Float height may be high.  If you have aluminum fuel screw, replace it with a brass one.

 

I have checked in the past and this is a recent happening. Used to start normal with choke a couple weeks ago but it wasnt as hot n humid as it is now. Just seemed going any lower on pj would be odd. 

I also have the jd jetting fuel screw, its quality.

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Probably gonna take a look at it tomorrow. I'll re-check the hot start and the boots for leaks. I should add that I re-packed my silencer while i was doing my top end with the FMF pillow type stuff that was actually really easy to install. I doubt this would be causing any sudden issue. 

One last question I suppose....and I know it doesnt affect starting because I am not cracking the throttle when I start it but maybe the hesitating issue in the lower throttle turn range, if my AP squirt is TOO long, would it be enough extra fuel to make the bog? I know when I checked it it felt like it was about 1 second (but didnt stopwatch it) and it certainly sprayed 6ft or so/ missed slide. I have a #50 leak jet at the moment.

Edited by J_YZ2fittyF

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23 hours ago, ronbuell said:

I'd bet you didn't check float height and you have an aluminum fuel screw. Float height may be high.  If you have aluminum fuel screw, replace it with a brass one.

 

Gonna laugh but my fuel screw oring must have fallen out during carb install bc it was stuck up in there. I checked that thing first and lo and behold the oring was gone. Put a new one in and it started in three kicks with the choke on. Although it is also about 10 to 12 degrees cooler today but it's still a little bit rich I think on the bottom but it's a little Chuggy down low

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3 hours ago, yz250f 78 said:

Was AP mod done? Tie arm to spring

that is your bog! 

What year is bike?

Yep actually threw a new oring on that for heck of it when i was doin bike work. Ap squirt was strong, missed slide, perhaps even too much duration. Would that be causing it?

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Possibly, actually "too much fuel" can cause a bog as well... and I've seen that little o-ring cause a multitude of issues.  I had mine stick up in there, stay on the fuel screw, crack and split but stay together, crack and split and fall off the fuel screw.  The last carb rebuild kits I bought had brass replacement fuel screws, so I used them.  Temps can play havoc as well... that's why you need to adjust the fuel screw.  We routinely adjust while riding out on the trail.  I like mine to pop on deceleration, so I watch and listen for it.  If its not popping enough I'll lean it out, too much I'll richen.  Never more than 1/2 turn though in 1/4 or 1/8 turn increments.  Small changes make huge differences.  Hang with it, you'll get it!!!!

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