I'm thinking of putting a 280cc or 300cc kit onto my 4RT, other than changing the barel and piston are there any other mods that need to be done. I think witht he 280 kit it is just change the parts but with the 300 you need to modify the crank cases, is this true?

Also will I need to put a programable throttle body on with a different map in the ECU?

Matt

Go for the 280 mitani kit, easily fitted, no mods, the 300 and 320 heads need crank case mod, for not much more go, unless you fit the new injector. Twin map TB is recommended and I'd go for the 27 or 30 mm header pipe and mitani titanium silencer to complement the extra breathing the 280 needs, gives more torque too, also sounds nicer without more noise ( actually it sound quieter) and is about half the weight of the original. The Termignoni header and carbon silencer gives more power, is almost as light as the mitani and sounds TDB's. If you Have a spare £2k floating about, you won't be disappointed.