Ok, I'm looking for my first real motorcycle.
I'm selling a '62 Pontiac Laurentian and I've got a fellow offering me a trade for a 1979 Yamaha XS650.
These seem like decent bikes, is there anything I should know?
The engine looks like a Japanese version of the Triumph Bonneville engine.
Thanks guys.
Shawn
I don't think that anyone in the history of the XS650 has ever modified one. 
Well, I have found a metric ton of info on the interwebs but this forum seems to be the most honest and least biased place around.
That's why I asked here 
They are great bikes. Look good stock, look good bobbed, make great cafe racers, and are the best looking tracker next to a Harley. There is a huge aftermarket to support them and they are. CHeap and easy to get parts for.
Love mine. 
Great bikes, there's a lot of aftermarket still and they are a great blank canvas. '79 might have rear disc brake, if so that's a plus. It would also have points, that's not a plus. But there are a couple of good electronic ignition conversions out there.
The only real weak points in the engine are the electric starter gear #4, if it grinds like hell and disengages it needs a new one. The front cam chain guide has a plastic piece bonded to an aluminum backing and this can separate. If you pull the front sump cover and find pieces of black plastic, it needs one. The engine has to come out of the frame to replace the damn thing. 
Lots of good info and a good all around forum: xs650.com
Parts: mikesxs.net 650central.com
Thanks for the info.
It has wire wheels and a rear drum brake.
Now I know what to check for when I have a look at it.
Shawn
No, a 79 wouldn't have rear disc brakes. I have an 80 XS650 sitting in the corner of my garage. It has drum rear/disc front. Simple to work on and that engine just loves to lug. Has both a kick and electric start but if the battery is dead, kicking it won't start it. Learned that the hard way. 
They do vibrate. A lot. The engine is solid mounted. I even put foam grips on mine to reduce the vibration to my hands. This is the main reason I stopped riding mine. I have some nerve damage in my right elbow and hand from a motorcycle accident (not on the XS650) and the vibration would cause my fingers on my right hand to become numb. Great bike otherwise. And looks good however you want it, stock or modded. Because of the way the engine puts out power, I think it is a great bike for beginners and experienced alike. Power rolls on smoothly without making a big display of it. Nothing like the sound of a vertical twin. Plus they just look cool. 
The only thing I ever had trouble with is the electronics, they're just expensive.
Dan
Rusnak_322 wrote: I don't think that anyone in the history of the XS650 has ever modified one.
I had a real jonesin' for the XS650 back in the day... now I have it again
Damn.
I had a boner for one back when they were new, too. This picture had a lot to do with that, it's King Kenny Roberts at the Peoria TT.
The XS is probably the most versatile thing Yamaha had at the time. They were successful at flat track, TT and road racing. I've heard of people putting knobbies on them and going desert racing but never seen it.
Then there's this pic:
Oh yes. eVil thoughts abound. 
that be cool
Rumor has it that re-phasing the engine helps a lot with the vibrations.
http://www.dotheton.com/forum/index.php?topic=448.0
I want to do a rephase on mine. It's supposed to cut down on vibes and the engine revs more freely. But if I'm going that far it's gonna also get a 750 big bore kit and a Shell #1 cam.
There's two rephases, a 277 (easy, press the crank apart and reassemble) and a 270 (not so easy, requires custom machined crank center pin). That 7 degrees is supposed to make one run really smooth but it ain't cheap.
Rumor has it there is a 1000cc XS650 out there somewhere: 270 rephased stroker and pistons machined from Wiseco blanks. If you have ever looked at the bottom end of an XS and seen the size of the crank bearings, I bet a liter version will live.
The level of vibration is relative...I used to own a '74 650 Yamaha and it wasn't all that bad, compared to other bikes I've owned. At least it wouldn't shake loose parts and drop them on the highway.
About the vibes: on mine I don't really notice it once off of idle. They came with rubber mounted pegs and handlebars, if the rubber grommets are in good shape it won't be objectionable. Now, having said that: if the carbs are not properly balanced it will vibrate like a jackhammer at idle. I learned on mine that if the cables on the VMs are not properly synced it will idle good, then as you just slightly open the throttle it will shake like hell till both carbs open.
And no, even at its worst it does not shake like a certain outdated V twin design.
That engine is popular with the chopper crowd right?
In reply to 4eyes: here is a article on re-phasing I did a few years back. http://www.xs650chopper.com/2009/06/rephased-xs650-chopper/
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