I too am interested in converting my TW125 to 225cc. I´ve riden pretty much everything over the 25 years I´ve been riding and have the TW as a good-looking little London traffic buster - a task at which it is highly competent. However, more torque and a smigin more power would certainly make an improvement - especially to beat the Chelsea tractor brigade away from ´the lights´. I´m trying to establish whether a SEROW engine/carbs etc would fit the frame - I´m guessing that it would without too much grinding re-welding of mounts, etc and I´m not sure about the compatibility of the TW wiring loom with the SEROW coil, condensor, alternator, etc. ANyone know of any serious pitfalls with such a conversion?? Please please don´t anyone say - ´Just buy a SEROW mate - it´d be much easier´. That´s not the point really. The TW is a stunner with low centre of gravity and wide but low ´bars - the Serow´s bars would hit all the London wing mirrors!!