Big TX500 project, any help appreciated!

The 500 was one of Yamaha's rare failures,, as was the 750 twin....
They should've just stuck with the 650, bored it to 750 and given it a 90* crank like they did with the much later 850. Live and learn...
Not so sure about that. Maybe some of the poor sales was caused by the issues the 750 had, and sharing the "TX" family name surely did the 500 no favors. Something the change back to "XS" for the 650 clearly indicates.
Looking at its design features, it is really a very advanced engine for its time:
Having the timing chain outboard, allowed closer cylinder centerlines, minimizing the unavoidable rocking couple that comes with a 180 degree crank. So better than Honda twins in that respect.
It was definitely the first multi cylinder street bike from Japan with a 4 valve head, and only Honda 450 and Kawasaki Z1 had DOHC at that time.
The balance shafts had a much better location than on the TX750, and their chain had a tensioner.
48 hp from a 500 twin is also pretty good, the equivalent from a 750 would be 72 hp ( which only the very best XS650 based racers could match), and the equivalent from a 653 cc engine would be almost 63 hp. Which would be very good for a hot street XS650 with a big bore kit.
Geesh! Keep going back and forth !! Found a 76 engine but that fell through.
As an owner and rider of both the 500 and 650, if it was my choice on where to spend the time and cashola, I would definitely go with the 650. The 500 is great, but the knowledge and parts availability is pretty much zilch compared to the six-fiddy. JMHO.
Just kidding of course. I’m well aware that the pre 76 500 engines were prone to hairline cracks in the head. I received a counter offer for a 75 @ $425 buckaroos , will probably pass. I’m also looking for some 78-80 xs650 and they are pricey !! But beautiful bikes.
Moving ahead on a deal like this can't be rushed. If you insist on throwing, well you know, the world will accommodate. With patience the right doner will show. Meanwhile a for sale ad might cure the whole problem .. 😉
Well…. I just loaded up one of my bmw bikes to a buyer. Have some cold hard cash to spend now.
I’ve decided to sell the Yamaha, wanted to restore but the more I research this thing, the more challenging and expensive it will be.
That’s it! That’s all I have!
Yes, they can be expensive but keep looking, a good deal will eventually pop up. There are lots that have been sitting in garages or barns for years, never put up for sale. If you get lucky, you may stumble across one of those and be able to get it cheap. That's how I got both of mine. One was $200 and the other was free. Of course, it costs you a good $1000+ to fix it up but being so cheap to begin with, it's not a bad deal.
I’m actually looking at some 650’s and some are very pricey $3-4,000.

I picked up an '80SG for 500 bucks. It ran, but was otherwise pretty sorry for itself. $1500 later (2k counting the initial cost of the bike) and I had a fully restored SG. Granted, all the engine work, welding and more importantly/costly, all the paint was done by me. That saved a ton of money, but the biggie was patience and scrounging. Wait long enough and the part you're looking for will eventually turn up on Ebay or here on the forum at a reasonable price.

This is a hobby that can be as spendy, or as cheap as you make it.

Before and after....


There’s a really nice 78 xs650 3 hrs from me, supposedly fully restored and wanting $2500.
Looks really nice but I’m going to take my time shopping. I really want a winter project.
I’ve restored old goldwings for years and just want to try something different.
Here’s a pic of my latest build completed. Before & after :) Took 9 months.


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Wow!! So yesterday I posted two bikes for sale. The 500 and I have an 84 wing sort of a parts bike.
The 500 already had over 600 clicks and the wing only 30. They are both reasonably priced to sell fast . Looks like there’s more of an interest in the old 70’s bikes these days for sure. Look at me and what I’m wanting to do :)