Hello, I am about to reseal the rusty tank on my 87 GSXR 1100 with POR 15. I have done this a couple of times over the years on old tanks but I noticed this one has a vent that needs to come off. I looked at the parts diagram and it looks like it just screws off but I wanted to check around for technique. The tank is pretty much mint and I wasnt expecting to do this until I took it off and drained it and crap came out along with the debris I can hear in it now that all the fuel has evaporated. So do I just use pliers and piece of old inner tube? Are they screwed on pretty tight? I dread this.
For the smaller, non-CA vent I use 2 sections of weld rod or similar rod to fit into 2 of the ventcheck scallops then use a visegrip on the rods to turn the vent out in normal lefty-loosy (CCW) direction. Do not touch the vent with the visegrip or any other tools - it appears to be potmetal and marks very easily. Most come out easily but if it seems very tight, spray the thread area with liquid wrench or WD40 and let sit for a day. If you have to force it, it may twist off and require an easyout or drilling it out which is doable - remember to wash the subchamber out and blow it out after! If it was put in without copper grease it may be seized.
Cleaning - if not obviously rust-caked inside, it doesn't necessarily need to be coated; just remove & seal petcock and vent holes(silicone the bolt threads!), fill tank to brim with CLR or rad cleaner, let sit for a day with occasional sloshing to move any rust off surfaces, drain and follow with gasline antifreeze rinse(s). Biggest prob in Calgary is getting rid of the used CLR (down a drain followed by water) or rad cleaner (gas station or hazardous disposal). Oh - and make sure the tank is sitting on a sealed surface, like a plastic or rubber drainage tank, as any leaks will chew up your concrete floor! Easypeasy!
Great to hear from people that have already done this. I'm going to try a rubber glove and the "death grip" first. I did a badly rusted V65 magna tank a few years ago and used muratic acid. While I saved the flawless paint I swear the tank mounts didn't line up properly afterwards, maybe something else was going on as the paint didn't wrinkle but I can't explain it. The sub tank did spring a leak so I had to get a new one of those. I followed up with the POR 15 kit.
Im going to fab a block off plate for the bottom and I typically use a rubber freeze plug for the top opening but this one is not perfectly round so I might have to rethink this, maybe locate an old cap or something. Ideas? I was just going to use a bolt in place of the top vent. The only other vent I'm aware of is on the rim of the gas tank to drain overfilling. I take it there is another vent somewhere inside the tank?
There is a relatively new product called evapo rust that won't harm paint and has great reviews but I'm thinking it needs to be sealed with POR 15 to preserve the tank and all the nasty E85 we have now. I already have the POR 15 kit and think I better stick to the POR system.
Vents/holes - gascap (use the gascap as the inner metal can probably use a refresh anyhow but its rubber seal may leak as it is OLD so don't leave upside down very long at all); top vapor vent & underside overflow vents (use a piece of rubber tube with a siliconed bolt in it); petcock (use an old petcock or make a seal plate and attach with siliconed bolts). Coating - I don't do that, too many risks of blistering off & plugging things esp with the ethanol in fuel - just clean the tank and keep it full of fuel and the water out!