Question about Bike Kits.

Hi All.

Maybe someone can help me with the following problem.

Today I visited a new area close by and found a shop that stocks a lot of older Kits.
Among them were 3 Tamiya Motorbike engine Kits in 1/6 scale:
Honda CB750F
Honda CX500 Turbo
Kawasaki Z1300

Does anybody know if more kits like that were released, I am specifically wondering if they ever did any Harley Davidson engine in the same way or if I got the whole series?

The only 1/6 Harley Engine I know of is a metal kit and costs around $300, which is too steep for my pocket.

Thanks, in advance.