Fuel tank warping, good ending

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   Thought I'd service my Tuono's 15 yr old pump so ordered new filter, hoses, flange seal to do the job just once and fully. Made a hand pump to drain the tank, disconnected all the connected bits and removed the tank. I could see the pump had been out before and had been stuck/bonded back in with A LOT of black goo, looked like it was silicon based . 
Two hours later with a modelling knife and patience, the pump was out, another 30 mins cleaning the flange surfaces and it was clear why the sealant had been needed. There was at least 1mm of waveyness on the tank base between each pair of bolt holes. Arse, should have let sleeping dogs lie.....

Anyway once all the fumes had cleared I got to work with the hot air gun repeatedly warming and pulling the tank base back into shape until after about another two hours I could barely get a thin feeler gauge blade between the tank and a steel ruler. New seal in place, bolt the rebuilt pump back in and 'hand tightened' until it felt 'right'. Added a cup of fuel, left it 24 hours, no leaks! Added a gallon & repeated, no leaks, excellent. 

I'd been a bit dubious that a tank could be properly straightened this way but I think I've got away with it, more time will tell but hopefully it's a good ending. Interestingly I had been looking for some confirmed fuel resistant sealant just in case, couldn't find any manufacturer who would commit their product but I'm sure someone will know of something that works.  

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MikeyR Members Profile Send Private Message Find Members Posts Add to Buddy List Moto3 racer Joined: 12 May 2020 Location: Melksham Status: Offline Points: 85	Post Options Post Reply Quote MikeyR Report Post Thanks(0) Quote Reply Topic: Fuel tank warping, good ending Posted: 23 Feb 2022 at 16:31
	Thought I'd service my Tuono's 15 yr old pump so ordered new filter, hoses, flange seal to do the job just once and fully. Made a hand pump to drain the tank, disconnected all the connected bits and removed the tank. I could see the pump had been out before and had been stuck/bonded back in with A LOT of black goo, looked like it was silicon based . Two hours later with a modelling knife and patience, the pump was out, another 30 mins cleaning the flange surfaces and it was clear why the sealant had been needed. There was at least 1mm of waveyness on the tank base between each pair of bolt holes. Arse, should have let sleeping dogs lie..... Anyway once all the fumes had cleared I got to work with the hot air gun repeatedly warming and pulling the tank base back into shape until after about another two hours I could barely get a thin feeler gauge blade between the tank and a steel ruler. New seal in place, bolt the rebuilt pump back in and 'hand tightened' until it felt 'right'. Added a cup of fuel, left it 24 hours, no leaks! Added a gallon & repeated, no leaks, excellent. I'd been a bit dubious that a tank could be properly straightened this way but I think I've got away with it, more time will tell but hopefully it's a good ending. Interestingly I had been looking for some confirmed fuel resistant sealant just in case, couldn't find any manufacturer who would commit their product but I'm sure someone will know of something that works.

Stevex Members Profile Send Private Message Find Members Posts Add to Buddy List Moto GP Alien Joined: 05 Jul 2016 Location: UK Status: Offline Points: 1481	Post Options Post Reply Quote Stevex Report Post Thanks(0) Quote Reply Posted: 23 Feb 2022 at 22:13
	The manual tells you to use Loctite 518 when installing a new flange o ring. I used aircraft fuel tank sealant although my tank didn't appear warped; just belt and braces as I didn't want to have to revisit the pump refit.
	People say I don't know Jack Sh1t; but I do, he lives next door.

Bladerunner919 Members Profile Send Private Message Find Members Posts Add to Buddy List Premium Member Joined: 19 Mar 2020 Location: Bracknell Status: Offline Points: 405	Post Options Post Reply Quote Bladerunner919 Report Post Thanks(0) Quote Reply Posted: 24 Feb 2022 at 09:04
	I've had my Mille tank off the bike all winter and I need to do exactly this before refitting it. It'd be good to lose the permanent smell of leaking petrol!

MikeyR Members Profile Send Private Message Find Members Posts Add to Buddy List Moto3 racer Joined: 12 May 2020 Location: Melksham Status: Offline Points: 85	Post Options Post Reply Quote MikeyR Report Post Thanks(0) Quote Reply Posted: 25 Feb 2022 at 11:22
	SteveX, I com[letely missed the loctite 518 recommendation but good to know about effective products that are out there, cheers.

ajaycad Members Profile Send Private Message Find Members Posts Add to Buddy List World Superbike Star Joined: 25 Jul 2020 Location: Hayle, Cornwall Status: Offline Points: 238	Post Options Post Reply Quote ajaycad Report Post Thanks(0) Quote Reply Posted: 27 Feb 2022 at 10:31
	I made the mistake of using black threebond, sealed the pump assembly fine however the excess on the inside of the flange o ring reacted with the fuel and clogged the tea bag filter !! Invested in Loctite 518 as recommended and made sure none ended up on the inside of the o ring...been fine ever since.