beta 525 rr w/ leo Vince and JD jet kit

getty weird cut out at 1/4" throttle and has been dieing in a few corners.

I'm thinking Pilot jet

I'm here in Texas 300 to 900 ft

weather is 65-70 degrees

40 to 70 % humidity...

42 pilot

178 main

blue needle 3 clips down..

has a good squirt form the ap (it's modded)

Pilot circut screw.. turn in all the way.. high idle.. turn out 1/2 and idle drops.

so I'm thinking I need to go down a pilot to a 40 to see if that will cure the issue.

Just looking for verification and thoughts?

what fuel screw are you using?

forgot the name brand..

it was recommended by the dealer to be the better of what he had in stock and of course it was the more expensive unit than the annodized unit with numbers etc

it's silver aluminum with 1/8" grooves machined in dial.. no knurling, numbers or zero marks has an additional o-ring at the base.

the aluminum screw is.......... well "screwing" you.they are never machined correctly.

I just picked up a 525RR, what fuel screw do you reccomend then for that carb?

merge racing

thank you sir

Well.. no luck so far. thought I had it fix but nope.

put stock fuel screw back in same problem

changed needles ( stock/ jd red) changed a little

moved clip down.

check valves and all electrical(swapped with a friends exc) didn't change problem.

here's a video of the bike in action

only thing I haven't checked

what does it do when you ride it?

engine starts easy and idles takes off good from a dead stop. as I am riding along it Feels like it's missing or jutters as I crack on the throttle or hold throttle at 1/4 or 3/8 steady then at about 1/2 throttle if freaking takes off like a fire breathing dragon. rips my arms off.. does a wheelie. then I have to back off and then it sputters and sometimes stalls as I enter the corners. then it doesn't want to fire up right away and slowly the engine turns faster and faster then it will start (electric start)

if I could ride it like a 125 there would be no problem.. but his is a 510cc ktm rfs motor.:doh:

two things I'm thinking I need to check/chang out is Needle jet and making sure the AP is timed correctly, then changing the floating slide and o-ring.

Went down to a 40 pilot and that seemed to get rid of the missing and cutting out.

took it to 3 mechanics. non could figure it out and didn't believe I should be running a 40 Pilot.

oh well. if it works.. I'm riding

replace the needle jet (what the main jet screws into).

replace the needle jet (what the main jet screws into).

just replaced that today..

throttle is crisp and clean

now she's throwing flames out the exhaust.

figure I need to change back to the 42 pilot to see if that cleans it up as I'm more than 2.5 turns out will need to reset the pilot circuit.


were back to hauling the mail

rode 30 miles of trails today without any issues.

bike's power is just awesome.

finally she's running perfect again....

what an ordeal.... never had a needle jet go bad before..

at least I know what the symptoms are for this problem.

kept everyone scratching their heads for a while..

Start with checking the accelerator pumps action, your statment "its modded" tells us only that its been messed with, stock was screwed up but screwed up and then messed with is whatever it is. At first twist we want a strong stream which ends in abt 1 second. Anytime you have an AC pump you need to ride smoothly, if your wrist is twitching your going to flood the engine!

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