Been getting some feedback from members of yamahaydsownersgroup, in response to some newbie questions I posted there. A lot of people lean towards staying stock. One response in particular contained some real good stuff, so thought I'd pass it on:
Safer/better/more reliable?--Number one is tires. On R5's the tires need to be updated to moderns---no ribbed fronts. Dunlops may be the only ones available in your bike's size. Number 2 either change the front brake shoes or have them rechamfered/grooved. Stock R5 front brakes come on very sudden and will toss you in a sec. Number 3 is replace the rear shocks with moderns. Number 4 is replace the swingarm bushings with bronze sintered, and just change the fork oil to good moly-based 10-15wt. Number 6 is replace the horn.
See where this is going??--Nothing to do with cafe or engine mods.
Only ergonomic item would be to go to low-rise euro-styled bars, also called "BMW bars". Please don't go to flat bars; you'll hurt your neck at best, won't be able to see at worst. The stock seat is a plank, but is still more comfortable than cafe seats. Leave the footpegs alone until later; most rearsets make shifting balky and make the rear brake less effective with shorter brakearm. Any concerns about grounding the stock under-pipe footpeg brackets is from old magazine hype. This was always magazines' complaint about R5/RD's.
This is a site dedicated to the 1970-72 Yamaha 350 R5 two-strokes. These bikes are surprisingly fast for their size and age, lifting the front wheel in the first two gears and keeping up with modern bikes twice their size. It's also extremely flickable and great fun around the city or carving up canyon roads. It was the direct descendant of the Yamaha factory TR production racers. Dirty, loud, crazy quick and relatively affordable when new (and more so now!), it was, and still is, a giant-killer.
I picked up an R5C for my first motorcycle a few years ago, and was frustrated with the lack of information on these bikes available on the web. The original purpose of this site was to document the process of bringing the R5 back to life. But as I spent time gathering as much relevant and entertaining information as possible into one place for my own reference, I thought it would be helpful to share it with people who are also interested in these bikes, as well as other Yamahas, vintage bikes, and cool motorcycles in general.