What have I done?!

[Scoobisteve]

I have a 2005 1200GS, just bought it a few weeks ago...changed all the fluids, and the valves were kinda noisy, so I thought I would check the clearances. Didn't seem to be able to get the cover off with the coach bars in place, so set about removing them. Prior owner was a fan of LokTite, so pulled out the map gas and still wound up breaking one off. The big one. Part of the frame one. I've spent 2 days trying to get the rest of the bolt out, (there's still about 1/2" of thread in there) and have made a mess. I've ruined $40 worth of bits, and have come to a point of defeat. I managed to drill all the way through the bolt, but the blackness behind the bolt freaks me out. I started the bike to see if oil sprayed out (no), but am unsure of my next move. Here are some pics if you have any wisdom for me...(let a real Machanic work on it next time?)

[Rougarou]

Have you tried reverse cut drill bits.  Really, really slow.

[dirtrider]

17 hours ago, Scoobisteve said:

I have a 2005 1200GS, just bought it a few weeks ago...changed all the fluids, and the valves were kinda noisy, so I thought I would check the clearances. Didn't seem to be able to get the cover off with the coach bars in place, so set about removing them. Prior owner was a fan of LokTite, so pulled out the map gas and still wound up breaking one off. The big one. Part of the frame one. I've spent 2 days trying to get the rest of the bolt out, (there's still about 1/2" of thread in there) and have made a mess. I've ruined $40 worth of bits, and have come to a point of defeat. I managed to drill all the way through the bolt, but the blackness behind the bolt freaks me out. I started the bike to see if oil sprayed out (no), but am unsure of my next move. Here are some pics if you have any wisdom for me...(let a real Machanic work on it next time?)

Afternoon Scoobisteve

 

If you keep messing with the broken bolt trying to work through that frame bar you are going get to the point that nobody can get it out. 

 

You might have it to that point now, difficult to tell from the picture. 

 

In any case, if you keep drilling off center it will get even worse. 

 

You need to unbolt the other side & whatever else you need to unbolt to allow that frame bar to swing away from the broken bolt, THEN you need to weld a washer on the broken bolt (quality weld ONLY on the bolt ). Either use a non-plated washer or grind the plating off on the washer that you do use (nice thick washer)

 

Then once you have washer welded to the broken bolt, then weld a nut to that washer, then back the broken bolt out.

 

My best suggestion is to get a machine shop, or a shop that has the equipment & expertise, to remove that broken bolt. 

[Scoobisteve]

Ok, I wound up getting the bolt out, but destroyed the threads...seems like some of the threads came off with the 1st half of the bolt that came out(it came out in 2 or 3 pieces)..finally got the wall of the bolt thin enough I could peel it off the wall with a thin chisel...I was looking into fasteners, Helicoil vs just tapping out to a larger bolt, and settled on a fix that may wind up failing, but if it does I don't have much invested in it. I bought some of the JB steel reinforced putty and packed it in with one of the many broken drill bits I had, then after a couple of hours drilled it with a 11/32 (?) bit and tapped it out to the original 12 x 1.75 bolt. Found a bolt at ace hardware that was an exact match (except not stainless) for $7...I tightened it to 10 ft/lbs, , I know thats not spec, but I was afraid to strip it again... I can't find the torque spec for that bolt.  I think the M8 right in front of it is 14 ft/lbs...If I do strip it, those threads will be easier to drill out again. If I wind up getting a helicoil, is the wall around that bolt thick enough to drill oversize at 12.4mm? 

[dirtrider]

9 hours ago, Scoobisteve said:

Ok, I wound up getting the bolt out, but destroyed the threads...seems like some of the threads came off with the 1st half of the bolt that came out(it came out in 2 or 3 pieces)..finally got the wall of the bolt thin enough I could peel it off the wall with a thin chisel...I was looking into fasteners, Helicoil vs just tapping out to a larger bolt, and settled on a fix that may wind up failing, but if it does I don't have much invested in it. I bought some of the JB steel reinforced putty and packed it in with one of the many broken drill bits I had, then after a couple of hours drilled it with a 11/32 (?) bit and tapped it out to the original 12 x 1.75 bolt. Found a bolt at ace hardware that was an exact match (except not stainless) for $7...I tightened it to 10 ft/lbs, , I know thats not spec, but I was afraid to strip it again... I can't find the torque spec for that bolt.  I think the M8 right in front of it is 14 ft/lbs...If I do strip it, those threads will be easier to drill out again. If I wind up getting a helicoil, is the wall around that bolt thick enough to drill oversize at 12.4mm? 

Morning Scoobisteve

 

The torque is:  --- rear frame to engine, bottom, (M12 x 50)  55 Nm --

 

That is a fairly important attachment bolt so you really should get some threads in there then torque the bolt to the prop[er specs.

 

If that joint is allowed to move  around it could eventually crack or even break the engine case boss. 

 

It looks like enough boss material to properly Helicoil. Just be sure to use a drill stop so you don't drill too deep into the crankcase. 

 

 

 

[Scoobisteve]

Ah, thanks so much for the illustration...I am going to go ahead and order one today from Grainger and just plan on it...thanks for the expertise

[Joe Frickin' Friday]

3 hours ago, dirtrider said:

It looks like enough boss material to properly Helicoil. Just be sure to use a drill stop so you don't drill too deep into the crankcase. 

 

The trick is to drill (and more importantly, tap) deep enough (without breaking through) so that the tap cuts finished threads for the entire length of the helicoil.  The tap will leave some incompletely cut threads at its max extent, and if those incomplete threads are at a shallow enough depth from the hole entrance so that the helicoil runs into them, then the last few coils of the helicoil get tapered in to a smaller thread diameter, and can bind your bolt when you try to screw it in.  Depending on the circumstances, this may split the boss, break the bolt, or result in inadequate clamping force on the parts you're trying to assemble.  

 

When you've got the Helicoil installed, screw the bolt in by hand and (after breaking off the helicoil installation driving tang) make sure it goes in far enough without binding so that it will definitely clamp the frame to the engine when you do the final assembly.

[dirtrider]

2 hours ago, Joe Frickin' Friday said:

 

The trick is to drill (and more importantly, tap) deep enough (without breaking through) so that the tap cuts finished threads for the entire length of the helicoil.  The tap will leave some incompletely cut threads at its max extent, and if those incomplete threads are at a shallow enough depth from the hole entrance so that the helicoil runs into them, then the last few coils of the helicoil get tapered in to a smaller thread diameter, and can bind your bolt when you try to screw it in.  Depending on the circumstances, this may split the boss, break the bolt, or result in inadequate clamping force on the parts you're trying to assemble.  

 

When you've got the Helicoil installed, screw the bolt in by hand and (after breaking off the helicoil installation driving tang) make sure it goes in far enough without binding so that it will definitely clamp the frame to the engine when you do the final assembly.

Morning Mitch/ Scoobisteve

 

Heilicoil does make 12mm bottoming taps. In the past (with blind holes) when I don't have a bottoming tap handy ,  after I have tapped as deep as possible with the tapered point tap,  I have ground the tip & first few tapered threads off of the tap then used that as a bottoming tap to clean up the last few threads in the blind hole. Not as good as a true bottoming tap but in alloy it works OK if using proper lube for tapping alloy & working tap in slowly. (remove tap often to blow out the chips)

 

Those BMW alloy engine cases are pretty darn thin so I really caution against drilling any deeper than the factory hole. 

[Scoobisteve]

Roger all that and thanks...after ordering the kit, I noticed that all the inserts are fairly short, probably 12mm...they also sell 18 and 24 mm inserts...should I use one of those vs the 12mm? I notice there's about 1 1/4 of thread on the bolt itself

 

[Scoobisteve]

kit includes: (10) 12-1.75 mm-1.5D MC Wire Thread Insert; 12-1.75 mm STI MC Intermediate HSS Tap; 12.4 mm Bright HSS Jobber; HIT15 Powercoil Hand Installation Tool; TB15 Powercoil Tang Break Tool

 

Don't understand what 1.5D is...

[TSConver]

Personally I would use a timesert for a critical bolt like that.  Much better than a helicoil.

 

https://www.timesert.com/

[dirtrider]

1 hour ago, TSConver said:

Personally I would use a timesert for a critical bolt like that.  Much better than a helicoil.

 

https://www.timesert.com/

Afternoon TSConver

 

A Timesert would be a difficult install through the frame pocket as the Timesert has a flange on outer end. I'm not sure how you would get that flange under the frame pocket without loosening & moving the entire rear frame assembly. But even if you could that would leave a very small ring for the frame pocket to seat onto.   

[dirtrider]

2 hours ago, Scoobisteve said:

kit includes: (10) 12-1.75 mm-1.5D MC Wire Thread Insert; 12-1.75 mm STI MC Intermediate HSS Tap; 12.4 mm Bright HSS Jobber; HIT15 Powercoil Hand Installation Tool; TB15 Powercoil Tang Break Tool

 

Don't understand what 1.5D is...

Afternoon  Scoobisteve

 

The suggested requirement for bolt thread engagement  in alloy (typically aluminum) is 1.5 times the bolt diameter so that 1.5D probably represents 1.5 times diameter.   You can get away with 1 times bolt thread engagement (ie 12mm bolt equals 12mm engagement) in steel & harder materials but for softer stuff like aluminum alloy you should shoot for 1.5 times bolt size thread engagement.   

[Scoobisteve]

OK, thanks for that...so a 12 x 1.75mm - 1.5D insert is 18mm long...looks like an Algebraic equation. Kit will be here today, looking forward to finishing this up, and calling it a lesson learned.

[dirtrider]

29 minutes ago, Scoobisteve said:

OK, thanks for that...so a 12 x 1.75mm - 1.5D insert is 18mm long...looks like an Algebraic equation. Kit will be here today, looking forward to finishing this up, and calling it a lesson learned.

Morning Scoobisteve

 

Just make sure that you use a drilling depth stop so you don't drill until you hit oil! 

[Scoobisteve]

HaHa Dirtrider, thanks for all your advice...I got it drilled out, tapped and new threads inserted...Torqued it down to 40 ft/lbs with no problem. Won't make that mistake again!

 

[MichiganBob]

It's threads like this that reinforces how good this web page forum is. Excellent outcome and knowledgeable guidance provided. Ride on.