TOPIC:

Many modern fuels do cause plastic tanks to swell, and I've had two Cagivas that needed the tanks lining to prevent degradation products from the nylon coming out of solution and clogging idle jets. Otherwise, it meant an annual strip of the carbs.
These days, I avoid the E5/10 issue by only using Esso 99 Supreme, which the makers demand is actually free from ethanol in most parts of the country. If you have access to Esso fuel and are willing to pay for top-grade stuff, It's worth going onto the Esso web-site to check on the current situation in your area.
Nick

Funnily enough I've been reading up a little about this today. My usual filling station I use for my Transalp is an ESSO outlet. I've been using their +99 E5 . It seems that in many areas there is no ethanol in their E5, although they are obliged by law to market it as E5. So, unless you live in Devon,Cornwall,North Wales,North of England (a bit vague,that) and Scotland, ESSO +99 should contain no ethanol.How long this situation lasts is anyones guess. I believe the top BP blend is the same and we use in our hillclimb KTMs with,to date, no adverse effects. This concurs with what Nick said in his post.