If your 800 sounds like a lawn mower check out the link
http://www.romanrat.co.uk/bulletins_12.html (http://www.romanrat.co.uk/bulletins_12.html)
Fuel Exhausts have just produced a silencer too road legal with removable baffle.
http://www.fuelexhausts.com/new-product ... ?newsid=70 (http://www.fuelexhausts.com/new-products-detail.cfm?newsid=70)
Someone posted a price on another forum Sub £200