Fuel tank - what a saga!
Posted: Tue Jun 23, 2020 8:37 am
A few days ago I was out riding the bike when I heard a tinny rattling noise. I assumed it was the regular issue of the top of the exhaust coming loose again. Strangely though, that problem is usually accompanied by popping in the exhaust and that didn't happen.
On getting home I checked the bike over and revved it. The rattle was coming from behind the engine and at first I assumed it was the head steady bolt come loose but on checking that saw it wasn't. Both rear tank brackets had broken free from the tank itself!
I took the tank off (it was only held on by the front bolt). The welds on the brackets had fractured; the factory had only tacked them on in three or four places. I had repaired one some some time ago. There was no penetration on the welds on the non repaired one, only four blobs "glued" on, inside the tunnel.
I drained the tank, took off the fuel tap and left it upside down for a couple of days in the warm sun to vent. I then gave it some extra heat from my heat gun to ensure it was clean inside. I then swilled it round with hot soapy water and drained it again and dried it out a second time. When I was happy it was safe to work on I ground off the old welds and paint and cleaned up the brackets for re-use. Unfortunately I then got called away from the job; SWMBO needed assistance on a "little project" that turned into a marathon taking the whole day - enough said.
On returning to the tank I tack welded on the first bracket, tried the tank on the bike for fit (perfect) removed it and welded it on for good. I then used it as a guide to fix on the second bracket. All was good so I did a leak check, using hot soapy water. All good! Those welds weren't going to come off!
I painted the damaged area. Etch primer, colour coat, petrol proof laquer. A good job all round. Until I tried to fit the tank on the bike....
I'm not sure what happened but somehow the brackets were just far enough out so the rear bolt would not go in. I think the tack welds were good, but the "proper" welding had caused some distortion. A case of rushing the job and distraction. I should have known better.
Needless to say, getting the brackets off a second time destroyed them - my welding was a lot better than the original. I needed new brackets.
I took a drive to my local Wickes where they stock assorted strips of steel in metre lengths. Queued to get in. none of the required size in stock. Queued to get out - social distancing etc! Best part of an hour wasted.
Went home, rooted around all the old tins and boxes of junk in the garage and eventually found an old bracket that could be cut in half and cleaned up and drilled to make two brackets. Fiddly job but eventually ended up with two brackets!
This time I made a jig from a piece of 4x2 timber using my pillar drill (should have done this the first time). Drilled it to match the frame fixings, making absolutely sure everything was "square". Bolted it inside the tunnel of the tank, bolted both new brackets to it and marked them up for welding. It was then I realised that the underside of the tank isn't true, the tunnel has a marked twist in it! My identical brackets didn't fit in the same positions inside the tank tunnel, one has to go further in the tunnel than the other. The tank was no doubt hand built and the tunnel wasn't lined up parallel to the sides of the tank. This partly explains my error in welding them on out of line - Doh!
So, having checked, rechecked and checked again, I tacked on the first bracket. Then I fitted and refitted the tank a number of times until I was sure both new brackets fitted correctly. Perfect. Welded them on securely . Still perfect!
Just final leak check then I can paint it again. BOTHER! Now there's a serious leak, apparently coming from behind one bracket . Cup of tea time.... with a lot of swear words between each sip.
Anyway, thankfully "only" a cracked seam weld next to one edge of a bracket. More welding. Leak check now OK.
Tank now awaiting paint to harden before refitting. Fingers crossed....
On getting home I checked the bike over and revved it. The rattle was coming from behind the engine and at first I assumed it was the head steady bolt come loose but on checking that saw it wasn't. Both rear tank brackets had broken free from the tank itself!
I took the tank off (it was only held on by the front bolt). The welds on the brackets had fractured; the factory had only tacked them on in three or four places. I had repaired one some some time ago. There was no penetration on the welds on the non repaired one, only four blobs "glued" on, inside the tunnel.
I drained the tank, took off the fuel tap and left it upside down for a couple of days in the warm sun to vent. I then gave it some extra heat from my heat gun to ensure it was clean inside. I then swilled it round with hot soapy water and drained it again and dried it out a second time. When I was happy it was safe to work on I ground off the old welds and paint and cleaned up the brackets for re-use. Unfortunately I then got called away from the job; SWMBO needed assistance on a "little project" that turned into a marathon taking the whole day - enough said.
On returning to the tank I tack welded on the first bracket, tried the tank on the bike for fit (perfect) removed it and welded it on for good. I then used it as a guide to fix on the second bracket. All was good so I did a leak check, using hot soapy water. All good! Those welds weren't going to come off!
I painted the damaged area. Etch primer, colour coat, petrol proof laquer. A good job all round. Until I tried to fit the tank on the bike....
I'm not sure what happened but somehow the brackets were just far enough out so the rear bolt would not go in. I think the tack welds were good, but the "proper" welding had caused some distortion. A case of rushing the job and distraction. I should have known better.
Needless to say, getting the brackets off a second time destroyed them - my welding was a lot better than the original. I needed new brackets.
I took a drive to my local Wickes where they stock assorted strips of steel in metre lengths. Queued to get in. none of the required size in stock. Queued to get out - social distancing etc! Best part of an hour wasted.
Went home, rooted around all the old tins and boxes of junk in the garage and eventually found an old bracket that could be cut in half and cleaned up and drilled to make two brackets. Fiddly job but eventually ended up with two brackets!
This time I made a jig from a piece of 4x2 timber using my pillar drill (should have done this the first time). Drilled it to match the frame fixings, making absolutely sure everything was "square". Bolted it inside the tunnel of the tank, bolted both new brackets to it and marked them up for welding. It was then I realised that the underside of the tank isn't true, the tunnel has a marked twist in it! My identical brackets didn't fit in the same positions inside the tank tunnel, one has to go further in the tunnel than the other. The tank was no doubt hand built and the tunnel wasn't lined up parallel to the sides of the tank. This partly explains my error in welding them on out of line - Doh!
So, having checked, rechecked and checked again, I tacked on the first bracket. Then I fitted and refitted the tank a number of times until I was sure both new brackets fitted correctly. Perfect. Welded them on securely . Still perfect!
Just final leak check then I can paint it again. BOTHER! Now there's a serious leak, apparently coming from behind one bracket . Cup of tea time.... with a lot of swear words between each sip.
Anyway, thankfully "only" a cracked seam weld next to one edge of a bracket. More welding. Leak check now OK.
Tank now awaiting paint to harden before refitting. Fingers crossed....