Main Motorcycle: Triumph TR7
Join Date: Feb 2012
Location: Norwich, England
Other Motorcycle: T140
Extra Motorcycle: Most of another T140
The craze for special valve seats that would work ok on unleaded petrol was a con, and a surprising (and disappointing) number of engineering firms sepcialising in 'classic' cars & bikes cashed in on people's fears. If you were running an old iron-head bike or car, maybe it would benefit from (or in some cases definitely need) new steel seat inserts to replace the existing iron seats, when switching to unleaded. Otherwise, there's nothing to gain and a lot to lose (a fair bit of money, and the risk of loose seats in the future). The additives might act as anti-knock agents but unless running unusually high compression, there shouldn't be any knocking/pinking/pinging or whatever you call it on straight superunleaded. On straight ordinary unleaded there might be some pinking on heavy throttle openings, but it should be avoidable with careful riding.