13 replies to this topic

[penno350]

I have a blue plastic Bultaco trials tank which I think is an original item as it is stamped 1979 underneath. However, it doesn't look very smart as it is very discoloured. Has anyone ever tried or had any luck in cleaning one of these tanks up and if so can you recommend a technique? otherwise I understand they are more or less impossible to paint as they are porous and the petrol vapour will lift the paint.

I would like to fit it to the bike I am just finishing but it just looks a bit shabby.

[Dadof2]

I doubt if there is anything you can do with the tank. Have a look and see if there is a plastic identification code anywhere but this is unlikely on a 1980 item.
Depends how much you want to spend, but a bumper / plastics repair shop may be able to recommend something. These types of thermoplastic do not generally take paint and special porous backed / vented stickers used to be used.
Cheers
PS - Motorcycle screen polish or ArmourAll plastic restorer may be worth a try.

Edited by Dadof2, 04 January 2012 - 12:35 PM.

[bullylover]

Hello all. Penno350, somewhere in the Bultaco forum here there is quite a lot of information on this subject. One of the solutions was to sand the tank down and use a hot air gun to heat it all up and this will bring back the shine. I don`t know if it works or not. I think there is also a few posts in the twinshock forum as well. Good luck and good searching. The standard tanks on the 198/199`s and the A`s were polyethylene and the 198/9B`s were polycarbonate and were painted. Bully Lover.

[BOGWHEEL]

Dependant on what condition it is in -
A few Fine to very fine wet and dry's and then finish off with the glass stove top cleaner (white milky stuff). Put a shine on mine.
If you have fuel stains coming through, that is another story. With plastic body work and guards, using a very hot heat gun will draw out the colour, and then polish as above.
But haven't tried this on a fuel tank?

[Nigel Dabster]

any abrasive will ruin it. be very careful, is the fuel tap seal ok?

[BOGWHEEL]

Believe me - what i have stated above works and i will add a pic soon!!!

[Nigel Dabster]

BOGWHEEL, on 08 January 2012 - 12:23 AM, said:

Believe me - what i have stated above works and i will add a pic soon!!!

As it was never shiny why would shiny on a textured tank be good?
These tanks are being re made and are available from bultaco uk afaik

[BOGWHEEL]

My point being, light abrasives will not ruin the tank.
A shine is better than daggy, weathered and oxydised.
We don't all want to spend more than the machine is worth - just make it presentable and ride it.

[PSchrauber]

It depends to the point of view:

A: If the discoloring, ... is real nice patina it might look good too, it's may be better to preserve it as it is.

B: If there are discoloring and scratches from former abuse by a pre owner in combination with erratic painted logos you might not have any consederations about the texture because the erratic logos and scratches are so ugly that you have to get rid of them.

C: Mounting a brand new gas tank, (you get the gas tank as a replica as already mentioned here before), on a bike with has some patina might disturb the complete look IMHO too?

So as a gas tank has something of the "face" of the bike this question is not so easy to answer.


Show some pic's so any comments get a basis.

[feetupfun]

PSchrauber, on 09 January 2012 - 12:35 AM, said:

It depends to the point of view:

A: If the discoloring, ... is real nice patina it might look good too, it's may be better to preserve it as it is.

B: If there are discoloring and scratches from former abuse by a pre owner in combination with erratic painted logos you might not have any consederations about the texture because the erratic logos and scratches are so ugly that you have to get rid of them.

C: Mounting a brand new gas tank, (you get the gas tank as a replica as already mentioned here before), on a bike with has some patina might disturb the complete look IMHO too?

So as a gas tank has something of the "face" of the bike this question is not so easy to answer.


Show some pic's so any comments get a basis.

Total agreement - I love the patina of old bikes. I have a M198 with a discoloured but otherwise undamaged original red polyethelene tank and love the look.

[penno350]

Update. Nigel yes the tap is leakproof. Just had half an hour with some very fine wet and dry, some cheap plastic restorer and polish I bought of ebay and some colour cut. Got to say it is looking better and I will try to post some pics at the weekend.

[Lorenzo]

Penno -

Not sure if this helps, but here is an original blue Sherpa tank that I have; it has "1979" moulded into the underside just like yours:-





This one's never been on a bike, and so I believe actually looks as close to original as you are likely to see.

You can see that the finish is completely matt, as pointed out by Nigel.

[Nigel Dabster]

Lorenzo, on 12 January 2012 - 11:15 PM, said:

Penno -

Not sure if this helps, but here is an original blue Sherpa tank that I have; it has "1979" moulded into the underside just like yours:-





This one's never been on a bike, and so I believe actually looks as close to original as you are likely to see.

You can see that the finish is completely matt, as pointed out by Nigel.

get the wet and dry out then?

[penno350]

Mine's a bit more battle-worn than that but slowly improving!