Purpose of small bolt in bottom of head


Information and questions on GL1100 Goldwings (1980-1983)
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Oldbear
Posts: 289
Joined: Fri Jun 24, 2011 7:02 pm
Location: Linden, Alberta, Canada
Motorcycle: 1983 GL1100A Aspencade

Purpose of small bolt in bottom of head

Postby Oldbear » Thu Mar 12, 2015 10:44 pm



I was doing a valve set tonight and general check of the cylinder heads. I often put a socket to the bolts (light touch) looking for wiggles and loose bolts... I found one. The small bolt under the right cylinder head was loose. Tried to tighten it. No go, and it didn't want to turn out (just spun). Got the bolt out... it's snapped off around where the threads start. I re-did the head gaskets 10 years ago, valve set 2 years ago... nothing was loose then. I've ridden about 6,000 km with nothing but the standard old bike leaks.

My question is about the little bolt under the head. What does this bolt hold? The torque is only 8 ftlb.

I'm a few hours from being ready to ride and a few months from being able to do a head job to remove the bolt and repair it.


My wife is the greatest - she won't let me sell my bike - I'm less grumpy when I ride...

Earl43P
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Location: Elizabeth City, NC
Motorcycle: 82 GL1100, parked in Pa.
93 GL1500 Interstate DD
99 Valkyrie IS

Re: Purpose of small bolt in bottom of head

Postby Earl43P » Fri Mar 13, 2015 6:52 am

Once you remove the head you'll see whether that gasket leaked there.

If it hasn't yet, you can expect that it will. That bolt simply secures the bottom of the head, that area is an oil drain galley.
It isn't under oil pressure, but it'll leak without that bolt, almost certainly.

For the remaining thread, you should file it flat if it protrudes enough.
Then, shock it with a good rap with a center punch and a substantial hammer.
Next would be to use a left handed drill bit with the likelyhood that once you start the drilling, it'll simply spin itself out since the threads aren't bottomed, just engaged with whatever crud has built up. Might use penetrant, heat, whatever you are comfortable with.

Under no circumstances would I use an EZ Out. Last resort would be drill it all out and install a Timesert thread repair.
When all else fails, RTFM!

99 Valkyrie Interstate
82 GL1100 nekkid-ish
93 GL1500 Next!

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Oldbear
Posts: 289
Joined: Fri Jun 24, 2011 7:02 pm
Location: Linden, Alberta, Canada
Motorcycle: 1983 GL1100A Aspencade

Re: Purpose of small bolt in bottom of head

Postby Oldbear » Fri Mar 13, 2015 7:11 am

Are the head gaskets a "one time use only" item? I did go with OEM.

I have the lefthand drill bit/tapered bit combo. It was just late last night that I found this extra issue. I'll visit it tonight.
My wife is the greatest - she won't let me sell my bike - I'm less grumpy when I ride...

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RBGERSON
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had every year from 75 to 83

Re: Purpose of small bolt in bottom of head

Postby RBGERSON » Fri Mar 13, 2015 8:23 am

Yep one time only................................
HAD LOTS OF GOLDWING 75-83
NOW INTO 1500'S..RIDING A 1998 SE

FAIR WINDS,
RB

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Oldbear
Posts: 289
Joined: Fri Jun 24, 2011 7:02 pm
Location: Linden, Alberta, Canada
Motorcycle: 1983 GL1100A Aspencade

Re: Purpose of small bolt in bottom of head

Postby Oldbear » Sat Mar 14, 2015 4:59 pm

Every garage should have left-handed drill bits... or be able to borrow them from work. 20 minutes of stripping exhaust, engine guards and chrome to get a straight shot at the hole with the broken bolt. All for 10 seconds with the drill and magnet. Now I just need to get a matching bolt and I can button up and continue with the spring maintenance. :D


My wife is the greatest - she won't let me sell my bike - I'm less grumpy when I ride...


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