Worst sound in the world

[chilly]

Taking off the front fuel tank bolt and hearing a little part clink down through the bike, then on the floor.  

Picking up the small square nut and realizing where it came from because of the no-longer-functional spot-welds on the corners.  :shock:

Thinking about how hard it is to get the tank bolts back in in the first place, and realizing that you can't even see or touch the place that the nut came from.  

Getting a non-square version of the nut at the hardware store.

One hand in front of the cockpit holding a 12" socket extension up and over the radiator with the new nut in it the end.  Other hand behind the cockpit, prying the tank flange back with a piece of wood, because now the bolt can't 'just' go in... it must go in PERFECTLY straight, because the socket extension only fits up there over the radiator dead straight... and since you can't see either of them, so they better be lined up.

Blindly trying to find the end of the bolt with the nut-on-a-stick for 1/2 hour.

Swearing so much that your neighbor actually slams their window closed.

It's back on... but I'm selling this bike before the 36k service cuz there's no way I'm EVER taking that tank off again.  Seriously, I think I'm going to get a longer bolt and come up with the bolt from the bottom, then put the nut on the top.  Not as pretty, but this was nearly impossible.

[Bixxer Bob]

I thought of a solution, but you'll need the help of someone with a welder.

1.  Buy a nut the right size but the sort with a flange on that doesn't need a washer like this:

http://www.fastfixdirect.co.uk/code/nav ... ctID=34607 (http://www.fastfixdirect.co.uk/code/navigation.asp?fType=Fasteners&MainCategoryID=12&ProductCategoryID=287&ProductID=34607)

2.  Drill out the hole in the frame big enough to get some weld on but not bigger than the flange on the nut.

3.  Hold the nut up from below and screw a bolt into it (not your tank bolt in case it gets damaged).

4.  Using the bolt to hold it in the right place from the top tack weld it into place.

5.  Grind off any raised welds flush with the frame.

6.  Treat bare / scorched metal to prevent corrosion.

7.  Job's a good 'un!!!

Obviously,  take all the relevant precautions before welding (get the fuel line out of the way, get the tank well away, assuming it's an electric welder, battery will already be disconnected as you have the tank off but it's a good idea to disconnect the reg rec and stator too.  Not sure about the ECU, maybe some electrics guru can advise???).

[mittens]

havent actually had the tank off yet, so not speaking form experience here but:
Could you not use a die and cut a thread into the frame? Then get a new bolt that fits and just bolt it on?
Or is the frame to thin in that spot?

[TigerTrax]

Mittens idea makes the most sense.

It was the first thought that came to my mind.

Keep it simple!  I'd put a hex head bolt in there.

[oxnsox]

(edit) a good idea to disconnect the reg rec and stator too.  Not sure about the ECU, maybe some electrics guru can advise???.

Would definitely unplug the ECU. Can't see the finer electronics liking any stray currents

[Bixxer Bob]

havent actually had the tank off yet, so not speaking form experience here but:
Could you not use a die and cut a thread into the frame? Then get a new bolt that fits and just bolt it on?
Or is the frame to thin in that spot?

Was working form memory  so just nipped out and checked.  It's not mounted to the frame,  it's mounted to a web plate, only a couple of mm thick at most so not enough thread to hold the tank securely.  Thinking about it, manufacturers don't put a single washer on a bike that doesn't need to be there because it would eat into profits.  So if Triumph went to the trouble  of welding in a stiff nut, it needs to be there. IMHO..

[chilly]

Yeah, that metal gusset is just sheet metal.  The welding is probably the best solution, but that's a lot of work (all the little things... getting a dissassembled bike to a welder, etc.).  When the time comes, I think I'll try the thru-bolt from the bottom.  You can get to the area when the tank is off, so maybe get the bolt in there and have someone hold it (or duct tape) while you fiddle with the tank.  I could put a cool 8-ball cap on the end of the bolt sticking up.

[ChazzyB]

What about epoxying a nut into place underneath? Could you pass a very long piece of threaded rod of the correct size right down though the hole, wind a new nut onto it at the bottom end, dab some epoxy on it, pull it up against the gusset and then fix in position with another nut above while it sets.

[Bixxer Bob]

Don't think epoxy would resist the torque of doing up the bolt many times.

Maybe try the flanged nut I described earlier, but file out a hex hole in the steel web plate that fits the nut hex snugly, then epoxy it in from underneath with the flange stopping it pulling through.  That way the epoxy holds it in place, the hex hole stops it turning, and the flange stops it pulling through.  Comprede????