First Build - Confused 650 to Cafe (hopefully)


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Bismarck, ND

Been reading this forum awhile. Wanting to do a bike build for a long time (since I was a kid, I've wanted to build a car with my dad who's been a mechanic for 40+ years, but I have no space for another car and more interest in bikes now, and he's pretty tired of working on cars:)) and now that I have my major bills paid off and some free time coming up, it seemed as good a time as any. I love cafe racers, and even though it would be easy enough to just buy a modern day Thruxton and get the general look, what's the fun in that? Plus I love tearing things apart and rebuilding them. Word of warning though, this will be a slow build, as my wife has a lot of projects for me around the yard/house. I'm not suppose to touch anything until winter, but I can be sneaky.

So, trying to find an XS650 around here in ANY condition is a real challenge. Been searching for months and months. Finally found a younger guy about an hour and a half away who was selling one. He had found it in a barn or something and wanted to fix it up, but figured he was in over his head. He said the engine was seized, and he thought it was a '75. I told him I'd give him 200 bucks to buy it and he said he'd bring it down. If it was complete garbage, I could tear it down just for experience while I looked for something better (I've wasted money on less entertaining things:wink2:), and if it was good, then all the better.

When I got it, it looked like this. A real beauty queen, I know.

He already had the engine out and was trying to open it up. He got stumped at the cam chain. He was still sure it was seized. Oh well, I enjoy a good dissection. So it was a frame and an engine and a blue tub of parts.

The engine wasn't seized. Here's the valves. The left side is pretty full of carbon. The right side is a mess of carbon and rust.

Same goes for the cylinders. Left side doesn't seem too bad, right side is carbon and rust above where the piston was last resting.

And, of course, pistons are in the same boat. I assume water or air got in somewhere as it sat and wreaked havoc.

Here's the carbs, just for fun. :D

When I get some free time I'm gonna clean it all up and take some measurements and see where we stand with the engine.

Now, my main confusion right now with this bike is what it is, exactly. (Or what it was) The PO said it was a '75. There is no title (I'm working on that) and by the serial number on the frame, he's correct: 447-118xxx. The engine, however is a 256 '71 serial # S650-007xxx. Okay, no big deal so far. Not the first time an engine has been swapped. On MikesXS, they have a model id pdf. This is where I get confused. The tank is from a '70-'73 model, should that ONLY fit a frame from those years, or was that easy to change over?

Fine, if it was, but what about the passenger peg mounts? Were they beyond '73 in this style? Maybe I'm not reading it right?

Based on the serial number on the engine it is from an XS1B and it seems like a lot of the bike is an XS1B. It looks like you can see the Candy Orange peaking through on the gas tank, the rear shocks, and the upper forks running through the triple tree. Right before it was painted red and then black over that (most likely with a rattle can).

I was fine thinking somebody mashed a '71 into a '75 but that pdf with the passenger peg mounts kind of threw me. I don't see any obvious frame mods that would have made '71 peg mounts on a '75 serial numbered frame. I guess it doesn't matter, really, I just kind of like the history of it all. If it had been a more complete and obvious XS1B (and better shape) I would have considered restoring it, but it is too far gone. So either cafe or parts, depending on that title and the engine. :)

Okay, that's a long enough ramble of a first post. I will try to expand on things in the future as I get rolling. Thanks for taking a peak and appreciate the info and wisdom and help (and humor), now and in the future.
Front end looks 72 If the brake rotor is not bolted to the hub then it's nearly certain 72 front parts. ( a one year only deal)
Carbs are later 80-81

70 71 motor had no E start and the left exhaust valve cover has 3 bolts.

Gauges look like later model 78 or newer.
Shocks and swing arm look 71 I'm guessing a 71 chassis with a 72 front end and the VIN from a 75 LOL.

Kinda like that Johnny Cash song. One piece at a time.
Haha, thanks. I thought the carbs looked a fair bit older. The gauges and "chopper" bars seemed off a bit too. Anyways, I feel less bad about stripping it down and making it something different. I'm really curious how many bikes I have! :laugh:
Keep that piece of stainless that goes around the seat, if it's not bent or cut it has value. Lots of the early bikes got chopped, and mini ape hangers were a dealer option.
We all watched Easy Rider and wanted to be Captain America.

The front rotor looks like a later model, based on the shape and size of the holes in the rotor??

If you decide to part out, I'd like a chance at the front wheel.
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I agree Dave there is some strangeness to that front set up. I would like to see a pic of the rotor side.
gggGary, there was a time when I wanted Peter Fonda's bike in Easy Rider, too. Not so much Captain America, though.

racerdave, I will keep you in mind if I do. Either way, I plan on taking it all apart as nicely as I can and if there is anything I don't re-use, I will offer them to new "loving" homes. :thumbsup:
I will try to take a pic of the rotor side later today and post it.

It could be the fact that I dimmed the background (my garage is currently a mess with landscaping stuff) to make the bike stand out a bit better that is causing that front end to look funky. I'll take a pic when I run home at lunch and post it to be sure.
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That IDs it as a 71 head I think, they just tie the intakes together, the early bikes only had one choke so it would provide a start mixture to both sides, kinda reduces carb synch issues??? They also could be used as "real big" vacuum ports, wink.
That IDs it as a 71 head I think, they just tie the intakes together, the early bikes only had one choke so it would provide a start mixture to both sides, kinda reduces carb synch issues??? They also could be used as "real big" vacuum ports, wink.

Yes, this is correct. That is without a doubt a XS1 head. I'm betting you have a XS1 motor, you lucky devil. That head can be run on later model motors but I doubt someone went through the trouble of doing that swap. The strange thing is that you have post 1980 carbs. This bike is definitely a conglomeration of XS650 parts. But at least it's good parts.
That shouldered front wheel kinda looks like a tx750... though I imagine they also put them on other bikes. I agree it looks like a later rotor.
Haven't had a lot of time to work on the bike, but quick update, was stripping down the paint around the serial number on the frame to get a better look under the caked layers of paint and lo and behold, the actual serial number was under it all. Matching the engine, the frame is a '71. Not sure why a '75 number was stamped in later. Oh well, one mystery solved!
Conventional wisdom says you can't use that (77 up) rotor with that 73-75 caliper and fork, The later rotor has a deeper offset, wonder how they made it work....