Jim,

If you're refering to the .61 with the gold twist on head, I've got one. I've had it for years and it's one of the best engines I've ever had (been doing this for 50+ years; got lot's of engines). I was very careful with the break in and followed the instructions exactly. Mine has the long "tuned" exhaust, but I don't know if it really adds much to the performance. You're right, it's light and is a screamer. Easy to tune and easy to start. I think you'll like it.

Paul