I do not like the look of the clone motors. Why do the have to lay the piston to the back of those engine. I,m a Rupp fan! I like the 1970 and up bikes and the clones look goofy on them. I know they make good power and theres a lot of hop-up parts for them out there. I have HF 6.5 clone thats been in its box for over a year because I don,t like the way it fits in most my bikes. I have been throwing around the Idea of trying a Honda gc160 on a rupp and route the exhuast around and out the left side of bike under the seat like the original exhaust. Thats about the only new style engine that at least likes more like the flat heads other than they exited the exhaust out the front of the engine. All frames designed back in the day were for flat head engines. I hope that someone will buy Tecumseh tooling and reproduce some HS50 and HS40 again. Maybe over in China thats were everthing else comes from anymore.