My first bike was an SL-70, not big on speed, but so much torque I once dragged a 20" Dia. felled tree up a paddock hill (helping mum do a bit of landscaping age 10). Cool. The SL100 was like a superbike to me, until a friends older brother showed up on a shiny new XL125.....
This wild tracker has an evil 100cc's of power, nickel finished frame and custom made everything. It was built by Dave Miller for a client - He's been involved in MX since the late 70's and makes jaw-dropping Vintage track bikes - check out his page:http://www.davemillerconcepts.com/index.php
Moriwaki was behind some great names in racing like Gardiner and Phillis, and still manufacturing & racing today in Moto2 class and others. Always very exotic to my 70's eye.
While we tend to fawn over the jewel like European 50cc bikes, small Japanese models still seem like the junk we left behind in our youth... these 2 models have very distinct 70's cafe styling about them, and are tres cool.
A couple of very nice Yammy XS650's have been popping up on eBay, and selling quite cheaply for the marvellous amount of work that's gone into them. The crazy SR500 sidecar at the bottom has been going off - 22 bids so far - heres the link if you like a challenge: