Tanks and the modern fuel

[Dale Sonnenschein]

Thanks for the help guys. I did check the pure gas site, nothing closer than an hour from where I am. Is straight avgas too high octane for these old bikes?

73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r

[brian kirby]

No, it will work just fine.

Brian

[Dave Withrow]

another plus in moving to Missouri from Illinois is that I can get non ethanol 93 octane at the pump in town


Big Dave

[Dale Sonnenschein]

Thanks Dave, Rub it in!!

73 Jackpiner
73 Husky 360 WR/RT
76 Husky WR360
78 husky cr250
10 ktm 250xc
02 bmw r1150r

[tvrc18]

Brian have you used only race fuel in your tanks that failed with Caswell? I just did a Bultaco tank and plan on only using race fuel and now I am wondering if it will fail over time.
Terry

[brian kirby]

I have used a mix of race fuel and pump, none of it with ethanol. The problem is not the fuel in the tank after the application of the Caswell, its the inability to properly prep the inside surface of the tank and the oil/fuel already in the fiberglass.

Brian

[454MRW]

I have found that the best way to clean a tank that has not already been affected by Ethanol softening the original gel coating inside the tank, or even gas/oil mixture affecting it is to rinse the tank thoroughly with Acetone several times over a period of a couple of days. The biggest problem even if the tank has been previously unaffected is that Acetone will its self soften the gel coat if left in the tank very long, but it is almost imperative to leave it in the tank to the point that the gel coat starts to actually become tacky for the best chance of removing any oil residue. Extreme caution should be used to monitor the effects of the Acetone, because leaving it in too long can actually collapse or ruin the tank as it can cause the fiberglass to lose its shape when it gets too soft. The tank needs to be rotated to rinse the insides evenly while checking it frequently during the process. I generally tend to rinse a tank for 5-10 minutes at a time with about 1/3 gal of Acetone then dumping the contents completely and allowing a drying period after the first couple of rinses, then a couple more again followed by a longer drying period, and winding up doing single rinses with even longer periods of drying in between, often using a total of 1-1/2-2 gallons of Acetone depending on the condition of the inside of the tank and verifying a clean clear rinse of Acetone for the last couple of rinses, then application of POR-15 clear paint in 3 coatings usually done 10-15 minutes apart, but initiated right after the last Acetone rinse as soon as the Acetone evaporates from the tank leaving a slight sticky tank inside to help the first coating of POR-15 Clear paint to adhere. Do not shake screws or anything else inside a softened tank! Each subsequent coating of the POR-15 Clear paint is applied as soon as the previous coating becomes slightly tacky. Patience and close monitoring is key because the POR-15 Clear paint takes longer for the first coat to become tacky than the next coating and even sooner for the 3rd. There is usually not enough time to do a 4th coating unless the shop temperature is cooler than normal. I usually shoot for 60-65 degrees shop temperature. The POR-15 Clear paint will become more aerated on each subsequent draining which speeds up its becoming thicker and becoming tacky. I rotate the tank for at least 5-7 minutes each time I apply a coating, then drain it into a large mixing cup with a paint strainer, then re-use it for the next 2 coatings. I have been buying 6 packs of pints of POR-15 Clear paint and using 2 pints for 1-2 tanks done at the same time. Wipe the top sealing surface and just inside of the filler neck lightly after the last coating is drained. Also after it sets up to the point that no more liquid drips from any petcock threaded collar a large drill bit turned by hand can be used to clear it from those threaded collars, but do it before it fully hardens! It will be rock hard once it sets up, almost impossible to sand, so make sure to keep clean rags and some Acetone handy to wipe off any external drips on the tank as soon as possible, and no more coating should be applied over the set up coating. I use rubber corks for the petcock collar plugs and GORILLA tape over the filler neck while rotating as a cap will leak and POR-15 will permanently plug the cap vents, but even GORILLA tape will leak as pressure builds during rotation during rinsing and during coating, so caution is advised. Mike

Michael R. Winter
I enjoy rebuilding and appreciating Pentons!
1974 250 HS Pentons-1980 KTM 175-400'S
1975 Can Am 175 TNT & 77 250 Black Widow
1979 Husqvarna OR390
1976-78 RM & 77-79 PE Suzuki's
1974 CR250M 07 CR125R 79 CR250R