Help yx 150 won't rev up backfiring

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Ok here's the last pic I took today for you and this is what I know was causing a problem just haven't tested to see if it will fix the issues I have been having yet. You can see that this is the spacer between carb & intake tube and it was on upside down blocking much of the intake restricting airflow.

 
having the insulator spacer upside down will let air into the air/fuel mix and make it run lean.

also if it has a rubber seal make sure it is facing the manifold when fitted.

the timing looks out to me.
take the spark plug out, and then line them up
the T mark at 12 o'clock lined up with the notch in the case
and the mark on the cam gear should be pointing directly to the centre of the cam cover mounting stud
 
this is my YX engine, pic taken from slightly above to show the flywheel marking lined up

 
when you have the F is lined up at 12 o'clock,
is the little bump on the flywheel lined up central to the black pickup sensor just to the rear of the flywheel ?
 
One last pic. And yes the round deal lines up with the pickup when it is at F

 
I took some gauge pins from the machine shop I work at and figured out what jet sizes I have on there.

main jet- .043 which is a #110 main
pilot- .015 which is a #38 pilot

I am running a stock motor with two bros pipe and silancer should I keep it this jetting? I believe this is stock jetting
 
yeah they should be good for it to run

you need to see if it hesitates /stumbles first, then you can work out if you need a bigger Pilot Jet
then once the idle mixture is set right, do a wot run in 3rd or 4th for 30 seconds and shut it off.
then pull the plug and check the colour of the porcelain inside

then go up or down to give you a coffee colour
 
Sounds good. I got my carb boiling in the ultra sonic that we use to clean parts here at work. It should be perfectly clean now
 
yeah, just make sure you give all the ports etc a decent blow out with compressed air
 
Got it all together put gas line on and now it's pissin out gas. Took it apart and cleaned float needle about 7 times lol the rubber on the tip of the needle looks a little worn and deformed in going to try to find a new one just not sure where to get parts for this carb
 
image.jpg
Believe it or not I just took bike for a ride and it doesn't seem any better at all! Here's a pic of my plug man this things getting on my nerves

Thank you for any help u can give me
 
spark plug looks ok, maybe a touch lean.

what is it doing, and at what revs/throttle position ?
 
1/4 turn throttle it spitts sputters and bogs. Won't rev up at all past 1/4 turn even slowly.
 
Now I can't even get it started plug out kicking it by hand and I see no sparky :(
 
have you checked out the head? my gpx 125 did this exact same thing after i did the valve clearances, i had done them with the flywheel slightly off tdc without realising it had rotated around that little bit. turns out with my hi compression motor the clearances were that tight that i managed to bend a valve stem and put a hairline crack in the piston. i no that doesnt explain your lack of spark now, but if its still not revving at all, might be time to pull the head off.
 
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