Glass fibre petrol tanks and problems with Ethanol in pump fuel.

[dave higgins]

Hi john-boy, i will be riding it at dorset, a bit of work on the inlet port & a decent mikuni carb have made it a bit more tractable, so if your there, stop by!.
As for the fuel type used, tesco momentum 99 octane, which was the same fuel that rotted it in the first place, and does contain ethanol.

[johnu]

A couple of years ago I tried a product called KBS Motorcycle tank sealer kit. It is designed around metal tank sealing, and comes with a rust converter.
I needed something to seal up a cracked fibreglass Montesa tank - local fibreglass shops weren't interested, so I tried this.
I used the aquacleen, skipped the rustblast, then straight to their Gold standard sealer.
I rode the bike for about 12 months, it always had fuel in it, no sigh of a leak.
Having said that, I always used non ethenol unleaded 98octane.

Mike

I just used this product on my tank, it better bloody work! I think I am going to use race gas anyway just to be on the safe side

[Andy Z]

There 2 main problems with using any of the commercially available sealers.

1) The interior of the tank must be absolutely clean and dry, which can only be achieved by multiple cleaning with water-based cleaners like muc-off, then a final clean with acetone.

2) The lining resin must be properly cured before using the tank. This can only really happen fully if the resin is cured in an oven, otherwise uncured components in the tank will dissolve in ethanol.

If these steps are not followed, then the tank lining will partially dissolve and fall off. Doesn't matter if its Caswells, Slosh, whatever.....

[dave higgins]

Andy, there are two diifferent types of sealer, single pack & two pack, the latter is cured by adding a hardener to the resin....no heat or anything else required & is the better of the two.
As for cleaning the inside, yes it has to be clean & substancially keyed, for the resin to bond to, but the two pack sealer forms a tank inside a tank & sets harder than the f/glass resin itself, curing after 7 days, so my advise ( having done it succesfully ) is if you cheapskate & buy a single pack resin...then you only have yourself to blame..........

[gribley]

Another problem is that glass fibre tanks become porous, the oil from the premix soaks into the pores preventing the liner from bonding.
I bit the bullet and commissioned an alloy tank from Holtworks

[dave higgins]

Hi gribley, as you can see from my avatar...so did i, i don`t think you are going to be dissapointed.....superb handcrafted tanks.... but a good solid f/glass tank can be saved & its not gonna give you sleepless nights worrying about denting it....

[gribley]

I wouldn't have dared put petrol in mine, it felt a little spongy underneath

[Colin Sparrow]

There's a report coming up in the next Leading Link from a chap who cut the bottom out of his 25DD tank and fitted an alloy tank inside the original.

Looks pretty ingenious to me.

[John Wakefield]

There's a report coming up in the next Leading Link from a chap who cut the bottom out of his 25DD tank and fitted an alloy tank inside the original.

Looks pretty ingenious to me.

Didn't Montessa do something similar with the Cota trials bike, although the alloy tank was I think a separate item with the fibre glass 'dummy' tank/seat unit fitting over the top.

[Brian Thompson]

Monty alloy tank under fiberglass cover.

Hi John,

You're spot on there...here's a link with some pics (scroll down to see the tank.)

Another advantage with this idea of course is that the 'inner' alloy tank wouldn't need to be cosmetically 'perfect', just functional.

http://teflonmike.craywiki.co.uk/0_Lo_040_Features_028_ClasBikeArt.htm

Brian.

[Andy Z]

Hi John,

You're spot on there...here's a link with some pics (scroll down to see the tank.)

Another advantage with this idea of course is that the 'inner' alloy tank wouldn't need to be cosmetically 'perfect', just functional.

http://teflonmike.craywiki.co.uk/0_Lo_040_Features_028_ClasBikeArt.htm

Brian.

Brian, you beat me to it! My 1979 Montesa 349 has the alloy tank under a fibreglass cover - it was a standard fitment.

[Brian Thompson]

...do you call it python.....(sorry mate, couldn't resist!!!)

Wotcha Andy,

Great minds and all that, eh!.....but where can we get some from mate (mind's, that is...)?!!

Brian.

[Andy Z]

Wotcha Andy,

Great minds and all that, eh!.....but where can we get some from mate (mind's, that is...)?!!

Brian.

Great to see you back on form Brian!

[Phil Hyde]

E10

Just returning from a trip to Aus (NSW) E10 is the norm here, for modern cars. Our hire RAV 4 went like a rocket. The stuff certainly has a unique smell.

Coming to us soon.

[smithkiwiboy]

Non Oxygenated fuel

Sunoco and VP both make non oxygenated race fuel that has no ethanol or other oxygenated fuel additives that will attack the fiberglass tanks.

Expect to pay about £100 plus for a 20-25Ltd drum.

You may also need to drop down 1 - 2 main jets.

Hope that helps.