T5 woun't rev.

Hi my T5 mark 1 wouln’t rev at all. It will start OK but if you open it up it just begins to splutter.
It was fine at first then it gradually got this bad over the space of 30 miles or so.
Put a new flywheel side oilseal in but this wasn’t the problem!
Help!!!

It could be many problems. Start with simplest first the spark plug and work back. It could be an electrical problem so check all your conections in the cdi box and renew any dodgy looking wires. Strip and clean your carb with compressed air or if not available an aerosol carb cleaner. Failing all that the other thing which would cause those symptoms is a blown drive or clutch side seal. If its this you will see white smoke from the exhaust and also the plug will be oily. BTW the flywheel side seal would cause an airleak and not the symptoms you have described. Hope this helps mate[:D]