Why did factory teams use aluminum tanks back in the day?

Hi Mike, I am interested in getting a similar tank to yours for my own bike. Could you please let me know where you purchased it from? Jamie

I too wondered and thought it was for weight but seems this is not the case at all.

As already said somewhat, would think as the development of the pre.prod/ prototype evolved, frame angles, geometry, mounting positions may all have changed overtime/ experimented with and the tank too would/may have needed to be adapted to fit the changes. As the cost of making plastic tank for a one off(that may need changing again) is not viable then ally was the choice. Could be altered/ cut / re-welded or even a whole new tank fabricated rather than being restricted to using a stock plastic tank with its inabilty to be modified.

Interesting point what the OP asked why the 90's works type bikes may have often used stock type frames though and yet still chose the ally. There again, could some of these tanks have been somewhat custom made/ aftermarket manufactured rather than actual true 'works' items? Like the European VRP ones sometimes fitted to Mugen types and sometimes other smaller and obscure manufacturers. The VRP also had the air vents which aided breathing/ cooling which was a nice touch. Suppose it is down to if the Ally 'works' tank bolts straight onto a stocker or doesn't fit. Begs the questions, just how 'works' were these tanks exactly and maybe also just how 'stock' were these stock frames exactly?

On impact would imagine the ally to impact inwards and flex to a point, where as plastic may split dumping the fuel? There again, I hardly ever heard of plastic tanks splitting, so probably not that. The welds look lovely though but do not think it was for looks as often they painted them.
Seems abit of a mystery still...

I have been trying to decide on what to do as well for the KX500.

Maybe a partial graphic on the portion that hangs below the shroud?



Thoughts on just a scrub with a scotch-brite pad?