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seized pilot screw nightmare, help please?


EazyDuz
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Bit of background:

Exhaust popping on decel, changed gaskets and it still remains. One screw is fine and turns, but the screw for the carb which requires adjusting had a ruined head. There was a tiny bit of a head left so i purchased a JCB branded screwdriver and used that. When applying force the handle on the screwdriver came loose.
That is how tight the pilot jet is...

So i used a pinvice with a 1mm drill bit to create a pilot hole. I then made it bigger with roughly a 2mm drill bit. I put an allen key in the hole and it grips but it still wont come lose. I tried gorilla gluing the allen key too which helped but again the seal snapped and its still stuck.

My remaining ideas are:

1. leave it alone and put up with it popping constantly on decel.
2. Create two new holes either side of the centre hole using a pinvice with 1mm drill bit, then using a flat head screwdriver and trying again that way.

Any advice would be greatly appreciated.

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Personally i wouldn't drill any more holes in it,

once you do that its going to be "last resort" because if you put your flat blade screwdriver in and snap off the remaining sides your only option left will be to drill it out!

if you've got a hole in the centre I 'd consider a "screw extractor". assuming you're not familiar......its like a "tap" but with an opposite thread, so as you wind it in and it screws itself in, you are in fact screwing it in anticlockwise so the actual part , all being well will start to unscrew.

That is providing you're confident it is a screw in the first place and not pressed or sweated in! in other words it was not designed to be removed! but fixed in a factory set position.......somethings are!

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  • 2 weeks later...

I HAVE GOT THE SAME PROBLEM ON MY 535.

I HAVE BEEN TOLD THE ALLOY COULD HAVE OXIDISED AND SEIZED THE SCREW.

I HAVE ALSO BEEN TOLD VINEGAR WILL RID THE OXIDIZATION, I HAVE NOT GOT AS FAR AS YOU HAVE YET.

SO TRY VINEGAR OR WD 40 TO FREE THE SCREW.

GOOGLE NRP IN MANCHESTER YOU WILL GET A PILOT SCREW THERE.

IF YOU WIN LET ME KNOW.

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The popping is caused by air getting into the cans are they strait through? Altering the the air screw wont make a lot of difference, the screw its self, its probably Electrolysis and Oxidation you could try heat but only after the fuel has been removed.

The resort would be machining it out but that will depend on how good a engineer you are.

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it only happens on overrun. If the throttle is even 1/10th open when decelerating it doesnt pop. It hints at a lean low speed circuit.

Either way i intend to get a Drag next year anyway, i dont want to spend loads of money on this bike.

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