Plastic Fuel Tanks

[postoak_imp]

There's a question on one of those sites where you can ask about anything: "Why have bike manufacturers shifted to plastic fuel tanks?"

Everybody starts answering the question, but I wonder if the assumption is correct. Are most bikes made today coming with plastic fuel tanks?

[the Ferret]

some are but they are not doing well with Ethanol gas. Ducatis in particular have had issues with it with tanks swwelling.

[postoak_imp]

Would you say a majority of bike models have plastic or metal tanks?
Also what is a "seamless" tank like the new CB1100EX has?

[Frulk_imp]

Earlier Moto Guzzi V7Rs had plastic tanks and had issues. My 2009 HD XR1200 has a plastic tank and no issues so far. Im sure there's no stats on this but I'd be curious to see if black tanks in hot climates had more issues than those of other colors in cooler climates. I can't help but think, ethanol not withstanding that this plays an issue.

[LongRanger_imp]

I believe they're roto-molded nylon, not plastic, but it's best to avoid bikes with these things unless they're buried underneath other bodywork, for the reason Ferret identified. Moto Guzzi and Ducati both had significant issues with swollen tanks and had to issue worldwide recalls or honor warranty claims to replace them. Guzzi no longer uses them on the V7 line.

(Sorry Frulk, we were both typing at the same time).

[postoak_imp]

So is the EX tank nylon (which is a form of plastic) or metal?

[LongRanger_imp]

Someone will pipe up, but I believe they're metal (the '13's and '14's are metal). I've not seen a '17 in the flesh yet.

[postoak_imp]

So how are they seamless? Are they actually seamless or the seam just doesn't show?

[alprider]

Frulk :Black absorb the sunlight.....

And i guess erhanol expand more as normal gas with by heat...

[redbirds_imp]

New CB has a metal tank and I would suppose that the tank is formed by some hydraulic process and what seams are welded are then ground smooth. I also note that the new CB has a tank filler ring that would easily adapt to a tank bag ring and eliminate the need for a magnetic bag and tank scratches that may happen with same.