bpatton said:
Isn't the reason they banned the glass tanks in the UK because they split when you got in a wreck?
This is also the reason why fiberglass and plastic tanks are not legal for many bikes in the US. Metal is seen as a safer container for fuel, as it is less likely to split in an impact. On the other side, some could say fiberglass is safer in an impact because it won't spark as it slides down the road.
In the US, there are federal safety regulations (OSHA) that require metal fuel containers in any construction job. In addition, these metal containers must be color-coded to denote the flammable contents (Red for Gasoline, Yellow for Diesel, Blue for Kerosene, etc).
gtsun said:
We are not alone in this problem. A friend who has a Ducati monster is having trouble with the plastic tank expanding to the point that his handle bars now touch at full turn, and the area around the cap is closing up. We met another guy with the same. Duck says it's mostly happening in California. I thought glass and plastic tanks were outlawed for street use here?
Fiberglass and plastic tanks are legal for small manufacturers, as long as these tanks are legal in the manufacturer's home market. I believe the cut-off is 10,000 units of total sales. With regard to venting issues, California Ducatis are fitted with an activated charcoal canister that connects to the tank vent, and a second vent line to allow air into the tank. I believe both of these lines have check valves to prevent fuel spillage in the event of a tip-over, and venting of fuel vapors directly to the atmosphere. The charcoal line only allows venting out of the tank, and the other line only allows venting into the tank. It is not uncommon for these check valves to stick, causing some tanks to swell as the vapor pressure inside increases (like when a bike is left out in the sun). It is also fairly common for bikes with metal tanks to have the tanks collapse overnight in the garage (especially in places like California, where you can park your bike in the garage with a warm tank, and at 6 the following morning, that garage is 50F.
With my Speed Triple (2006 with factory plastic tank), it was common for service techs to switch the vent lines on the tank, as these lines were unmarked and looked identical. If this happened, the tank would not vent properly and the tank would develop a slight vacuum, making the fuel pump work harder and making the gas cap hard to open. Triumphs don't show swelling or caving in because the tank top is a sort of double wall, with a painted fiberglass shell over the plastic tank. Most of the Speed Triple owners I know have marked these vent lines so they don't get switched. I'm not sure, but I think the Ducati problem can be either a stuck check valve or swapped line. I'm not saying to do it, as it violates EPA rules, but removing the check valve allows the tank to vent directly to the atmosphere, with little chance of clogging.