We have 2 350 scramblers. They are a good bike, good decent engine and trans. Much better than the 360, not as big as the 450. They originally got around 100-110 miles/gallon. We are waiting to see what they get with this ethanol crap. There is no dedicated 350 twin forum I've ever found but there is a 450 forum and twin forums. They can be a lot of help.
The CB is the street version, the CL is the dual sport and the SL is the all dirt. It all depended on what you needed it for. The forks seem beefier on the CL than the CB. The tank and seat are slightly different but will fit each bike, you just need to pair them up. Like... the CB tank is longer, seat is shorter than the CL by an inch or 2 so it could travel longer distances on the road. Some really like the pipes on the CL more. The heat shields give good protection against the hot pipes. In that respect, it's all about what style you like more. The CB pipes will fit a CL and are easier to come by, but I like the CL look better.
Pretty interchangeable, some things are slightly different through the years. Fork ears changed just enough to make it inconvenient. We are leaving one bike more stock, one we are modding more to a cafe look but not completely. You will see that the forks attach to the triple tree with a bolt instead of sliding up through. Clip-ons won't work and you can't slide them up or down to change the rake of the bike. Maybe the CB is different so that should be a consideration.
In reference, we paid $450 for the '69 and it needs cables, tires, cleaned up, air filters, plugs, etc. We paid just a little more than that for a running '72 that needs the same things but came with a bunch of spare parts including a clean tank, forks, wheels, etc. Both had titles. I will warn you... the air filters are around $35 each. Unless you need new jets for some reason, just go to Honda and get the carb gasket kit (#1 on the fiche I think?) for around $11 each carb. It will save you $$ and it's better quality than the stuff on ebay. There are subtle differences on the carbs through the years but they fit the same and the gaskets are the same. The floats are a little different on the really early ones and won't fit the newer round style. The years you are looking at should be fine though.
We found it hard to find tires in those sizes without going totally knobby or paying through the nose for street tires. There are some nice, cheaper Avons that a few of the local guys use and swear by them. Parts galore on the net/feebay and they can be had for cheap so that is good news. I've really gotten some incredible bargains. Don't go cheap on the cables for the throttle. It's one cable, split into 2 and you want the tolerances to be dead on since it needs to open both with one pull equally. There is some adjustment in the mechanism but you don't want to have to fight it. The original cables were gray, many now come in black, even the ones from Honda. I like the black better so no biggy there but if you want gray, go to feebay.
The sidecovers will fit all years but some have vents some don't. The emblems changed a little on the tank and sidecovers. Otherwise, crossover in fitment. The tail lights changed a little but bolt on the same. The turn signals on the front fit the ears differently but are the same signals thoroughout. The seat latches differently from '68-70 compared to '71 on... after 71 it rolls to the side and can be locked, before that it lifts at the front and there is no lock for it.
That's about all I can think of right now. We're still learning a lot, cleaning out tanks, cleaning up bikes, getting parts together to do one massive blow out of work on them in the spring when we have more light and warmth.
Good luck!
