74 TX650A Project – AKA “The Parts Bike”

Mike G

Mike G
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Cleveland, OH
At the risk of rivaling Saint Paul’s Epistle to the Romans, here is the backstory. For those not interested in all the minute details of it’s acquisition please skip to the next post.

This project was kind of an offshoot of the previous project I posted on here which was an 80 SG which I called “Dads Bike”. For those interested or who would like a refresher it’s located at - 1980 SG Back From The Dead – AKA Dad’s bike | Yamaha XS650 Forum. When I first started on the SG, I wanted to add the bigger tank from a standard for some added range, standard bars (for obvious, at least to me, reasons) and spoke wheels just because I like them. I was shopping around for parts and the total cost of buying them individually was not really in the budget, so I put it on the back burner. About six months later I saw an ad in Craigslist for an XS650 without a title or keys for $800. From the pictures it was a 1974 TX650A so it had all the parts I was interested in. I called the number and talked to the owner and made plans to see it early morning that weekend which just happened to be Mother’s Day. When I went to look at it nobody answered the door after repeated attempts so, not wanting to waste the trip, I looked around and found the bike in a shed out back. Turns out it had good compression, shifted through the gears, was mostly complete except for a missing rear fender, taillight and turn signals and the left side cover. It had some rust but not horrible. It only had 2600 miles and still had what looked like the original Yokohama tires.

Before leaving, I figured I would try one more time to get someone to answer the door and this time a barely awake and not to happy woman answered in her PJ’s and bathrobe. I explained the situation and she said she had worked late shift and had only gotten to bed a short time earlier and that her son wasn’t there, but she could tell me what she knew about the bike and try to call her son. She explained the son did HVAC work on the side and one of his customers was short of cash and made up the difference with the untitled TX. She said he and his friend somehow loaded it into the back of a Honda Civic and (without mentioning it) stored it in mom’s shed. When she found out, told the son to get it gone ASAP so that’s when it showed up on Craigslist. The son and I haggled a bit, with mom passing messages back and forth over the phone, but he wouldn’t come down to parts bike dollars. The mother was getting pretty irritated and looks at me and says “How much will you give him?”. I said “no title, no keys, can’t see in the tank no idea if it runs”….and gave her a typical parts bike price. She goes back to the phone and says, “It’s Mother’s Day, I’m tired, I want it out of my shed…the bike’s is sold!” and he sheepishly agrees. She then helps me push it flat tires and all (still in her bathrobe) through the yard and up the ramp onto my trailer and writes me out a bill of sale. (for whatever that’s worth)
The Reader’s Digest version is I found a 74 TX650A without a title or keys on Craigslist that looked like it had been stored for 20 years with 2600 miles in so-so condition. I wanted it for some of the “standard” parts to put on a special.

This is what it looked like when I got it home. When I finally got the gas tank open it was almost spotless inside, petcocks are frozen, the shouldered rims and spokes look almost brand new, the carb throttle shafts are frozen solid and I’m wondering what put it out of commission at only 2600 miles. I still don’t know but I expect at some point I will find out.


Ohio is famous for making it difficult to get anything other than a replacement title and this bike hadn’t been registered since 1985 (according to the registration under the seat) so a title, if I could even get one, would cost almost as much as the bike is worth so part’s bike it is.
A month or so later I saw an ad on one of the (now defunct) XS forums for a free titled frame near Chicago for a 1975 XS650B but it had to be picked up in person in the next couple of days or it was going to the trash. I asked my dad and he said he would be willing to go get it so it seems to me the motorcycle gods want this one back on the road. The current plan is to swap everything over to the titled frame and that’s where this project begins, more or less as all this happened in 2010.

My first order of business is to try and get the engine running and get the bike somewhat rideable to see if it has any major engine/transmission problems. The last thing I want to do is swap the engine over and then find out it has major issues and then have to take it right back out for a teardown.

Step number one is the front brake. It was dragging a bit, so I removed it and tried to pop the pistons out with compressed air but no joy. I sprayed some penetrating oil on the pistons (without much hope) and let it sit for a couple of days. Next attempt was to use a grease gun which I haven’t had to resort to before and, while it worked, it sure makes a mess. The pistons have a bit of rust around where the dust seals sit but the inside of the caliper isn’t too bad.


The seals seem in decent shape, at least good enough for a test ride, so next order of business is new pistons. I have shafting scraps in 316 stainless from a previous job so this seems like a good time to use some.


I haven’t machined SS before and it was definitely harder to work with but after finding out which operations were difficult (boring) and which were easy (drilling, outside turning and facing) and grinding some bits to maximize the easier operations I managed to make a couple of serviceable and not too amateurish (which I most certainly am) pistons.



I told my son that if you drop the bike to the bottom of the ocean it will eventually decay into a small mound of nasty goo with two bright shiny pistons glinting at the outer edge. I know I could have bought a pair or replacement pistons for about $40 bucks so I can’t justify the hours (or the carbide boring insert I destroyed) based on dollars but I learned some things so it was worth the time and I have a fair amount of 316 scraps so I figured I might as well start learning how to work with it.
Next I tried the clutch lever and it was very stiff (big shock). I took it apart and figured I would drill the lever out and add an Oilite bushing but it already had a brass bushing, hmmm. I was surprised to find it had a standard M6 bolt with a separate brass pivot bushing versus the shoulder bolt that the Special had. The bushing had worn down to the bolt threads in only 2600 miles which was a pretty poor service life but not entirely surprising as brass on brass it not a good combination.


The bushing seemed like a good job for the lathe, so I found a shaft in the scrap box from a long dead ink-jet printer that was about the right size and made a new steel bushing. The material must have been leaded steel because it cut like butter and gave a very nice finish.


Even though the lever already had a brass bushing in it from the factory, it was also a bit worn so I drilled it out and replaced it with a new one. The clutch cable feels pretty gummed up so I will see if I can free it up with some penetrating oil while moving on to other things.
Next job is to remove the airboxes and carbs and see if the carbs are salvageable. I have a set of BS34’s and a set of later BS38 linked carbs and I will eventually put one or the other on (maybe try both) but for now I would like to see if I can get the originals working. The left carb slide and throttle shaft are stuck so hopefully will free up with some penetrating oil. On the right carb, the slide and shaft are stiff but did move after some penetrating oil so at least that one should be salvageable.(fingers crossed) After sitting overnight the left throttle shaft freed-up so now down to one stuck slide so things are looking up. I sprayed it with more penetrating oil and will try it again later. If it doesn’t free-up I will open them up this weekend and spray that piston from the top as well. Some stinky old gas came out of one of them so hoping they aren’t too bad inside. I wonder if the kid and his buddy tried putting some gas in them as I can’t imagine it remaining liquid for as long as it’s been off the road.

Also this is now officially 2/3 of a project.
Sweat-pushing it up the hill and into the basement. Check.
Blood-jabbing the utility knife into my finger getting the hardened drain hose off the float bowl. Check
Tears-plenty of time for that before I’m finished.

And now I'm caught up to today.
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I'm having a hard time believing that bushing got that hammered up in 2600 miles. Are you sure those are the original gauges?
:laugh2: How could he be? :laugh:

If I really wanted a stock standard in my collection, the TX650A is at or near the top of my list! (Except the mufflers. Man, those 74/75 muffs are ugly!)

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The other slide came free after a little more time with the penetrating oil, woo hoo!

I took the float bowls off and they aren't so bad either.


Is there any preferred direction for taking out the float pivot pin on BS38's? I remember the BS34's on the SG only came out/back in one way. Guess it's time to read the carb guide again.
You're right jetmechmarty, I have no idea if the miles are accurate. It only seems reasonable to me as the tires look original. The guages look original too in that they have the same "patina" (rust) as much of the rest of the bike and there aren't any (so far) buggered up screw/bolt heads.(Unlike the SG which had plenty)

I always liked the look of the standards and the Cinnamon is one of my favorite XS color schemes. Total fluke I ended up with one.
The guages look original too in that they have the same "patina" (rust) as much of the rest of the bik
I have an Eleven Special I bought with under 10K on the clock. Maybe. Same thing. No way to know for sure. I'm well beyond 100K now and it still pulls like a locomotive. I've replaced the speedometer twice and I've pretty much lost track of the mileage. I can't see how much good knowing will do me. It will run until it doesn't. I love the Cinnamon Girl!
Those float pivot pins towers will break pretty easy. Might want to cut a block of wood or metal so you can back both of 'em up before tappin' on the pins.

Yeah, kinda like when you jump off the diving board, doesn't much matter at that point what the water temp is, you will know soon enough.

Me too. And thanks for the Neil Young video, haven't heard that in a while and great reference.