Swingarm stiffening

This is the one on my KZ1000 no chain problems with this design, of course this pic is upside down though
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This thread has put me to thinking whether a TX750 swing arm might be a good upgrade on my '78 XS650SE. Have found a TX750 swing arm on ebay and have sent a query to the seller regarding model year. But my question to the wise people on this forum is, will a TX750 swing arm be a straight fit into my '78 frame? Cheers, Raymond
 
Thank you Superjet - I saw that but just looking for confirmation that applies across the years. I don't know by how much the XS frame changed - obviously, there was some strengthening and then further modification after about 1977? with the Percy Tait mods so just want to check the TX750 arm will fit.
 
I looked into one of the swing arm braces but decided I liked my center stand more.
 
The TX750 swingarm is a drum brake arm. Your SE model has a disc so some modding will be needed. The drum brake torque arm attaches to the bottom of the swingarm. The disc caliper torque arm attaches to the top. A bracket would need to be added for it.
 
Yes, the clearance is very close, but on the couple I've done, it fit. Tough to get a proper angle pic, the clearance is actually a bit more than what you see here, and it increases as the swingarm moves up when the shocks get compressed .....

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You do need to flip the anchor pin for the brake rod around. Put the thin head on the inside, cotter pin end facing outwards .....

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If you did have a clearance problem, it would be pretty easy to just bend the bracket on the pivot out a little bit at the top where the brake rod attaches.
Does the TX use the same brake pivot and brake arm as the later XS? If so, why no clearance concerns?
But if they don't use the same parts, would using those parts bypass clearance issues?
 
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The TX750 swingarm is a drum brake arm. Your SE model has a disc so some modding will be needed. The drum brake torque arm attaches to the bottom of the swingarm. The disc caliper torque arm attaches to the top. A bracket would need to be added for it.
Thank you 5T - that's exactly the sort of thing I needed to know. Will go and have a look at my swing-arm and have a wee think.
 
The TX750 uses a different brake pivot. The brake rod bracket on it steps out away from the swingarm, not towards it like the 650 one, and that's a good thing, but I'm not sure the 650 frame has enough clearance to allow for it .....

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But it would require some modding too. It doesn't have the small hole for attaching the brake light switch spring, and it doesn't extent up above the brake rod pivot hole enough to put one there. It also doesn't have the boss on the lower back side for the adjusting set bolt .....

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You might be able to adapt one but I think it's probably just easier to slightly bend an original 650 one if need be. And like I said, so far I haven't had to.
 
Oh, I'm sure there are many, lol. I just really get into and research the mods I do do. All this TX750 stuff I stumbled upon quite by accident. A buddy gave me a TX750 rolling chassis. He was moving out of state and didn't want to haul the thing with him. He had purchased it as part of a complete bike but just for the engine really. He was fixing up his dad's 750 and needed an engine (crank). I took it for the wheels mostly. They are the flanged alloy type like the 650 uses. Closer inspection revealed other useful items like the swingarm.
 
I`ve done 2 of these in the last 2 years. I used a curved side brace to get the proper clearance and a wider loop at the front. The no theme build started out as a drum brake but after I made the brace the linkage rod was too close to the brace for my liking so I switched to a rear hydraulic. I had to cut off the brake stay bracket from the bottom and weld it to the top of the rail. I didn`t really like the WiseGuy brace. Too crude for me. I`m getting ready to stretch a TX750 swingarm and brace it in the same manner. I like the placement of the lifting spools on Kevski`s KV1000 arm.
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Oh, I'm sure there are many, lol. I just really get into and research the mods I do do. All this TX750 stuff I stumbled upon quite by accident. A buddy gave me a TX750 rolling chassis. He was moving out of state and didn't want to haul the thing with him. He had purchased it as part of a complete bike but just for the engine really. He was fixing up his dad's 750 and needed an engine (crank). I took it for the wheels mostly. They are the flanged alloy type like the 650 uses. Closer inspection revealed other useful items like the swingarm.

Interesting the 750 brake pivot has only 2 holes, considering it would facilitate the brake lever, brake light switch, and return spring, i wonder if 2 of those would use the same hole?
 
5twins, I took your advice and mounted a TX750 swing arm awhile ago. It made quite an improvement. The TX750 arm is 2 lbs. heavier than the stock XS650 unit, but a hollow rear axle, modified plastic chain guard (from the salvage stash at the local independent shop, no idea what it went on originally), drilled chain adjuster stops, and a few titanium fasteners keep the unsprung weight at a healthy level. Thanks for the tip.
Sometime in the distant past past I got the notion that there was an engineering convention to assign half the weight of parts like swingarms and chainguards that connect unsprung to sprung vehicle components to each category; i.e., of the 2 lb difference in the swingarm, only 1 would be added unsprung weight. Anyone else confirm or correct me?
 
If you can find one, Radian swing arms are also easy conversions.
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This one will have different shocks installed, the nice looking CB900F shocks are just too long to work, darn it.
 
I don't think so. The bracket on the back that the brake rod connects to rotates front to back, just like the 650 one. The brake pedal moves up and down. With the brake light switch mounted above it, the pedal pulls it down to activate it.
 
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