Tx750 madness.

View attachment 188114 This is my actual rotor with modified sprag clutch.
I can’t claim the honour of this mod, it’s one I bought from a guy in Estonia. I wanted to get it fixed pronto when I first bought the bike. Apart from drilling and tapping six holes it’s a direct fit, whereas the R6 unit requires a spacer ring machining as the OD of the Sprag is smaller than the ID of the step in the rotor.

AHA! You actually have the Argo made clutch! I have been looking for that specific sprag for a few months. Can you take measurements of Argo's sprag for me? The I.D. O.D. and the width of the piece? I believe I found a drop on modern sprag but i need to confirm sizes before I order.
 
Thank you! The suzuki sprag that i found is 42mm x 94mm. I believe it should literally drop on besides having to drill and tap the mounting holes. Excellent. I am going to make a catalog of parts and corrections for the TX750 so any other that wants to bring one back reliably can do so.
 
I've had the joy of pulling the engine in and out of one of these.... a few times.... . We had a 73' with a locked up engine..... for the usual reasons.... I scored a low mileage 74' engine. Installed it.... and off the we went.. only to discovered he ran it low on oil.... rings went south.... so we pulled then engine..quick hone.. new rings.... stuffed it back in.. thankfully we have one of those old nursing home " people " lifters.. hand crank... In regards to the header cross over piece... that heavy finned part that bolts to the head.... it's hollow and exhaust remains with the undesirable heat.. read somewhere to solve the issue.. weld the openings internally closed... so I visited my weld'n guru.... We got it all sorted out and for a hefty bike it really haul'd azz .... handled well also. New owner in Colorado reports he's very pleased to have it in his stable.
 
I’ve always had a soft spot for the TX750, a friend of mine bought an orange one , just like Rasputin’s, brand new off the showroom floor. I remember being very impressed with it back then. Still like the looks.
It is a good looking bike. From a proportions perspective it's winner for sure.
 
It is a good looking bike. From a proportions perspective it's winner for sure.
When I was 13-14 years old, a poster of that bike was hanging on my BR wall. A large dealer brochure is what it was. I loved the 1973 Yamaha color schemes, particularly the TX750.
 
It is a good looking bike. From a proportions perspective it's winner for sure.
Judging by the bore and stroke, they used a few things learned from the 650 (same stroke)
I wonder if the design changes to the cylinder head was partially to make it look more like the CB750 ( Which was not an aesthetic improvement IMHO, but maybe reduced chances of oil leaks)
Mounting the ignition on the balanced shaft was not the best idea either, at least not from a exact timing and maintenance perspective.
But I totally agree on it being a good looking bike as a whole !
 
Judging by the bore and stroke, they used a few things learned from the 650 (same stroke)
I wonder if the design changes to the cylinder head was partially to make it look more like the CB750 ( Which was not an aesthetic improvement IMHO, but maybe reduced chances of oil leaks)
Mounting the ignition on the balanced shaft was not the best idea either, at least not from a exact timing and maintenance perspective.
But I totally agree on it being a good looking bike as a whole !
The ignition is mounted on the opposite end of the oil pump shaft.
 
Right photo.
 

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The ignition is mounted on the opposite end of the oil pump shaft.
Ok, I knew that it was behind the crankshaft, so just assumed it was the balancer shaft. So there is a dedicated shaft just for oil pumps and ignition? With a separate chain drive, or the same chain as the balancer shaft? I have never seen a TX 750 engine disassembled, so bear with me......
 
No problem.
The balancer chain drives contra rotating balance shafts from the centre of the crank.
 

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Thank you! The suzuki sprag that i found is 42mm x 94mm. I believe it should literally drop on besides having to drill and tap the mounting holes. Excellent. I am going to make a catalog of parts and corrections for the TX750 so any other that wants to bring one back reliably can do so.
Can you divulge the info of the Suzuki sprag clutch you intend to use. Thanks.
 
I have a NOS starter chain, and I will be making a tensioner for that. I'm still looking for a new balancer chain.
Good luck with the balancer chain. It’s very special, same as the starter chain only 2 links longer.
I had to pay €190 for the last one from cmsnl.
Starter chains are cheaper, I thought about buying two and extending one chain with two links from the other.
 
I would hazard a guess that these chains are nothing more than cam chains of some sort. Can't you get the size numbers off the side plates of the originals and possibly track down a replacement cam chain? Too long is OK, just shorten it and put a rivet type master link in it.
 
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