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Tank tunnel widening technique

7092 Views 23 Replies 11 Participants Last post by  mattsway
Hi. I have a CB200 tank to go on my XBR500 build and need to get clearance where my frame rails attach to my top tube. At this location, the tank tunnel is 130mm and if possible needs to become 160mm. Having googled around, I hope to be able to use a plastic mallet. Any advice on weight/shape of mallet and technique - do I strike against the inside face of the tunnel first, or the bottom edge where the wall and bottom of the tank meet? Any prep to help move the metal most effectively? I thought about filling with boiling water, but I could always purge the tank of petrol/gas fumes and use a butane torch. Many thanks.


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That tank is 2.9 gallons, down from the 5.2 gallons on the XBR500. Are you prepared to wind up with a 1.5 gallon fuel tank?

don't purge fumes with fire... if you must do something, rinse it out several times with water first
POR15 should solve the issue.

just make sure you follow the directions to the letter
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