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'71 Bonneville. Fuel tank "held" by central bolt which is reasonably tight, trying not to break the slotted plate the bolt head sits in. Plate slot is open to rear. Walks back and contacts frame, bolt does not come out of slot, but angles back. . Two U-shape buffers are in place on central spine. How to hold it in place? Looks like later oil in frame models reversed the slotted plate with closed end to rear. Lunmad's youtube videos show he's put layers of padding along spine, looks ugly. What do others do?
Doug
 

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Hi Doug

I have a 71 T120R frame (with a 73 Tiger 750 in it). A PO has previously brazed the bolt into the slotted bracket so it stands up vertical and cannot move. Seems to work!

Andy
 

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I extended the frame bracket towards the seat. I closed over the end of the slot so the bolt could not get out. Moving it all back a little, stopped any possibility of the speedo/revcounter brackets contacting the petrol tank. The fabrication was made up and i welded it onto the frame. Been good for over 20 years and solved the problem of the tank moving back and the bolt sliding out.
 

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Hi harroun, Sorry late to the party, I've been away for 3 days.

I've seen that before long ago. I've not had tank of '71 or '72 in a long time. I wasn't aware that the earlier frame had the bracket in with opening to the rear. My '73 has the open slot towards front. My tank will migrate back until it finds it's place. I've never looked into it but now after thinking about it, I expect my bolt is full back. I try to set the bolt such it comes up 90deg to back bone so bolt is not canted.

Regarding your bolt, I have a few thoughts. Would it be possible to drill the head & run thick steel wire (often known as bailing or mechanic's wire here) through the hole, then wrap around bracket to "lash" bolt to front or where you want it?

Or even just wrap wire around bolt head, front of bracket, then additional wires as needed to keep this wire from dropping down. I don't recall how much room there is around sides of bolt. I think not much. If you had room on sides you might make a sheet metal bracket around bolt head & then after installing bolt loosely, slide bracket over bolt head & bend ends of sheet metal upwards around the frame bracket??

Regarding the center bolt, is the spacer tube & washers correct such it puts correct tension on tank rubbers. Also the U buffers & center bolt top buffer in good shape & compressed properly. Too much tension from overtightening can over stress tank so just cranking nut down might not be good idea. I like to feel the tank wiggle on the rubbers fairly freely, meaning, not play in rubber/tank interface, but the rubber is free to flex because it's not over compressed.

So my thought is to figure a simple way to lash the bolt to the bracket.

My feeling is it probably won't take to much to hold bolt from sliding backwards. So wire should(??) be strong enough.
Don
 

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.......My tank will migrate back until it finds it's place. I've never looked into it but now after thinking about it,....
Once my tank migrated far enough backwards to where the fuel line on the right hand petcock slipped off and was draining fuel big time. Luckily for me I caught it just at the beginning otherwise there could have been a catastrophic explosion should the fuel have ignited.
 

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The tank is difficult to keep in place as overtightening of the centre fixing will pull the tank down and leave a dip in it. I have used some double sided tape on the horseshoe rubbers.
 

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Could you use a stud, or threaded rod, or a fully threaded bolt, and bolt it tightly to the bracket before fitting the tank?
 

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Hi Rambo, Then do you cut the spacer tube shorter?

I'm sure it would hold perfectly as you say. Good idea.
Don
 

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'71 Bonneville. Fuel tank "held" by central bolt which is reasonably tight, trying not to break the slotted plate the bolt head sits in. Plate slot is open to rear. Walks back and contacts frame, bolt does not come out of slot, but angles back. . Two U-shape buffers are in place on central spine. How to hold it in place? Looks like later oil in frame models reversed the slotted plate with closed end to rear. Lunmad's youtube videos show he's put layers of padding along spine, looks ugly. What do others do?
Doug
I have a 71 TR6 my slotted plate is open at the front, the frame is actually off a 71 T129R but I've had the same problem your having.
I jammed a plastic packer under the bolt head to hold the bolt in place tight, now its in the correct position I'm thinking of removing the tank throwing the bike in the back of the van and getting it welded in place permanently, sick of fiddling with it.
 

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I sent hours, nearly chipped my newly painted tank and nearly broke my girlfriend's thumb trying to get the nut to fit on the bolt before i took the tank back off and jammed something between the top of the frame and up under the bolt head. Then it was a piece of cake, that's why i'm thinking of welding it in place.
 

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I use a nyloc nut and fit it into a socket.It is very easy then. The threaded rod is cut so it is just long enough to be flush with the nut when tight. Next time the tank is off, i will do a photo of the welded up bracket on the frame and the rod arrangement. I have done away with the spacer tube that fits over the rod. The tightening down is onto the chrome tank centre trim which has a washer in it. My UK type tanks needed raising a little and the horseshoe rubbers were not suitable. I made up some simple wooden blocks that sat on the frame tube for those tanks. The large USA tank does sit on 2 horseshoe rubbers.
I can see how it is easy to damage the paint when fitting but have learned to be very careful over the years. A good idea to wrap foam padding to the clock brackets that can contact the tank.
 
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