I have an MC18 r5k model. the barrels have cracked and its been sitting in the garage for 5 years. i want to get this bike going again. but trying to find an engine is hard. are there any other options, could i fit the engine out of a mc21 or 28.

getting the barrels fixed is a no go as there cracked in the exhasuts ports. i orginally was going to put a 300cc kit on as it would come with everything i need but having for pay over 700 for that then having to get there pipes to match cannot afford or warrent that much money on the bike just yet.

any ideas peeps i have a budget of approx £500.