Rounded off head nut

[YZ250H]

Hi Guys,

Finally started work on the 250 motor  .
Problem - one of the nuts on the head is rounded off.  Before bonehead kicks in with comments on my spanner wielding ability it was done before I got to it .
It is in a bit of a tricky spot down between the fins, so the only thing I can think of is to grind a groove in it with the rotary tool until it "lets go" (without damaging the thread on the stud) and then try to remove it.

There must be other ways.  Anyone any suggestions .
TIA 

[Hoony]

buy a "Metrinch"  (brand name) socket for that size, they may work as they grip on the flats of the bolts/nuts instead of the Hex corners. worth a try. most tool shop will stock them or get them in (hopefully you can buy them seperate intead of a set)

[yzhilly]

Hey Tony have you got a single hex socket , like a impact socket and put a strip of emery tape over the nut and tap ya socket on ,stick ya tongue out to the left and gently increase pressure . If that doesnt work ,swear,abuse me and tap the top of the nut with a nice square edge pin punch and try again good luck

[Lozza]

If you can get on the side of it whacking with a centre punch can move it enough to get another socket on there.

[vandy010]

sticking your tongue out to the left only works if your left handed!
think carefully about this first and make sure you stick your tongue out to the appropriate side.
HTH

[pokey]

Drill two  holes opposite each other in the nut so only a thin wall remains then split the nut with a chisel. Voila its off.

[Freakshow]

i

Drill two  holes opposite each other in the nut so only a thin wall remains then split the nut with a chisel. Voila its off.

like that idea, must remember that one - but also remember not to drill into the thread, which would be my luck !  :'(

[Doc]

..put the other 5 nuts back on and simply plead ignorance 

failing that you could try tapping (rather firmly) on a 13mm a whitworth or sae socket of similar size instead of the 14mm (11 instead of 12 depends what fitted)

[pokey]

easist way  is if you have enough thread to put another nut on top .... screw it down hard  and lock the nuts..... then screw the stud out

[DJRacing]

Pokey that would be the easy way but I think the nut YZ250 is talking about in an ali deep reach nut so the stud doesnt thread through.

[YZ250H]

I knew I could count on you blokes for some ingenious solutions All really good thanks.

I tried the alternate size socket Doc - no joy  :'(

Doc's other idea of putting the other nuts back on is the easiest , but I need to have a look in as there is not too much compression  .   
I think I will try Hilly's solution first and see how I go.  I guess it will be a bit of a progression from there to the more drastic measures.  One thing I'm not short of is tools (my father inlaw's).  Just have to make sure I put them all back or he gets the sh1ts .  He doesn't have any Metrinchs though, so I must mention how great they are 
Pokey's drill idea is excellent and will certainly work.  Mind you my luck's a bit like Freaky's so easy does it.
Unfortunately I can really only get at it from the top.  Not enough thread to get another nut on and the other ones where very tight.  It's just an ordinary garden variety nut on top of the head - nothing too special DJ.

Soo now all I need to do is work out which side to hold my tongue on and it will all be plain sailing .
Thanks again guys - some great tips.  Hopefully i don't have to use too many of them.  Old hat for you blokes, but great info for us newbies.
Cheers

[yzhilly]

No left side for undoin & right for doin up ,that way you know which way to pull the drive bar !!!. If you have one of those butane solder irons use the heat torch  to warm the nut up might loosen it and you can hit it hard enough to distort the nut a little.