Helicopter

Hi all, This is my first posting on your Forum and thanks for letting me join. My name is Colin, From North Devon and I am semi retired, have to keep doing a bit to fund my hobbies, namely Land Rover ownership, playing with my former inshore lifeboat and flying, also my enduring love 2 wheels! Now for a question if I may, although I ride my Diversion quite a bit I find myself using my Jog RR more and more, because of it's lightness and my painful back. Last week I fitted A Malossi 50cc sports cylinder kit with VERY disappointing results, as it appears to have a very narrow power band. I went for the 50cc kit rather than a 70 because of it's mileage (13,000) and not wanting to put too much extra strain on this mature engine. Anyhow, I have tried everything this former aviation engineer can think of in the way of jetting and adjustments but after an initial power surge on take off there is nothing left. Apart from the Malossi cylinder kit it has a 17.5 Dellorto carb and Leo Vince exhaust, Malossi reed valves and variator. Any help or advice would be much appreciated, as I am so bitterly disappointed I've reverted to the original cylinder and the thing buzzes once more, thank God. Colin (Helicopter)