Lee, the inserts are easily sorted. You either spend £3 on a full alloy arm or get the new EU spec style horns, that kit includes metal inserts instead of the plastic ones.
Oh and the Novarossi's, they really are awesome and you can do it on the cheap too. The 21 R10 has similar internals (some say the same) and performance to the Plus 4 engine. I own a Plus 4 and Chris owns both a 21R and a Plus 4C, all of our engines were incredibly easy to break-in, tune and the performance when tuned is amazing. 10 minutes on a tank no problem, won't give you any bother and with the 21 R10, it can be done for £135!!
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