Snapped EXUP valve bolts off flush with header. Can't drill bolts out to re-tap.

Helldiver14

New Member
Recently I heard a rattle in my exhaust, so I decided to investigate by removing the exup valve and seeing what was in there. After doing some research later I found out that some FZ's after awhile will develop a rattle from the small bushing/washer located on the exup valve. Well through the process of removing the cover, I snapped two bolts holding the cover on flush with the exhaust. I used very little torque and they just decided to snap (again, heard this was common.) I thought well, drilling these out shouldn't be an issue, boy was I wrong. I can only drill out maybe a quarter of an inch and now I cant go any farther. I've gone through 4 bits to see if they were the problem and even tried a Dewalt Cobalt bit and still can't drill through that bad boy. If I could just get it a little farther to tap I would be good, but I've ran into a brick wall it seems like. Does anyone have any ideas how I can drill any farther into this bolt so I can get a heli-coil or something in there? I've completely ran out of ideas and patience.
 

smittynsc

Member
Since you have already drilled them it may be too late but I have welded nuts (or washers) to broken off bolts and let it cool. This works often. Sometimes I weld a bigger nut to the first one just to add heat.
 

super googan

New Member
Only thing I can offer is try low rpm while drilling and keep lubricating the bit. High speed and no lube will just kill the bit faster.
Take your time.
 

delbert

Member
What size drill bit you using ? ,, start with a 1.5 mm or similar and work your way up in small increments , time consuming but the only way :)
 

Helldiver14

New Member
I started out with a small bit and slow speed, really seemed to get the job done. I got the drilling far enough and wide enough to insert a heli-coil. Tomorrow I'm going to clean out the crevice with a q-tip and apply a thin layer of JB Weld in there for the heli-coil to be inserted. Wish me luck!
 

aclaytonb

New Member
I just replaced my whole header with a fleabay Unit for $60. Machinist wanted $100 to drill and tap the broken bits and I've done it before with poor results. Took 20 minutes to swap the header - simplicity and lack of hassle were worth it.

Sent from my SM-G970U using Tapatalk
 

wallydude440

New Member
The same thing happened to me eight years ago. I took the header of and took it to my local Yamaha dealer. The dealer was able to remove the broken bolts and charged very little....can’t remember, maybe $30.
 
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