It's past time to start XS2 Resurrection

5twins said:
I'm thinking that whole design proved to be a failure. Costly to build and prone to bearing failure. If it was so good, all bikes would be like that, right? I don't think I've ever seen another with that funky set-up.
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Are you talking about the front brakes or the rear fender mount system. What you said could apply to either.:D
In any case they are what they are. The brakes did work OK. Never gave me any problems in many thousands of miles. But when dealing with old things sometimes it's interesting how they did things before they found what worked better. Or was cheaper to build.:geek:
 
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5twins said:
I was talking about that weird front disc mount.
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Yup, I’ve stared at it and at Mailman’s posts on the subject and the reasoning behind that very complex and over-constrained front disk arrangement completely eludes me. The term over-constrained means that there are too many support points on the front axle shaft - and any misalignment will cause binding. Preventing that binding would require a very high level of precision - which nearly always drives costs up.

The practice in most good design offices is to search for parts that can be eliminated from, and not added to, an assembly.

Very odd indeed and as pointed out, it’s uniqueness and the fact that it was dropped in subsequent years is a clear indication that someone at Yamaha started taking their medication again for the 1973 MY design.

Pete
 
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MaxPete said:
The practice in most good design offices is to search for parts that can be eliminated from, and not added to, an assembly.
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I believe it was Jack Northrup who said... "If it ain't on the airplane... it can't break." Sound engineering logic.;)
 
Pete you and 5T I think are correct. There was no real advantage to this setup. Only advantage was not having to mess with the breaks when removing the wheel. Not enough to justify the added expense. Hence 1 year only. I don't mind the added aggravation of this setup since this is a bike from my youth. Plus I like unique things. Might be why I still have a Hurricane.
 
Nice work around on the rubber bumpers for your rear fender. On your chain guard , do you have a photo that shows the notch you had to make? I’m just curious, as I have thought about aftermarket shocks too and I wondered just what would be required to make them fit.
Things are looking good! :thumbsup:
 
Mailman said:
as I have thought about aftermarket shocks too
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Not a big notch. Don't see it from the left. But the notch size will depend on the shock. I do remember the BM shocks were a very good improvement from the factory shocks. If your replacements don't have the springs all the way to the bottom of the shock you may not have to do anything.
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GLJ said:
Pete you and 5T I think are correct. There was no real advantage to this setup. Only advantage was not having to mess with the breaks when removing the wheel. Not enough to justify the added expense. Hence 1 year only. I don't mind the added aggravation of this setup since this is a bike from my youth. Plus I like unique things. Might be why I still have a Hurricane.
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Yup - it sure is looking nice GLJ and don't get me wrong, I do like these early XS650s!

I am just puzzled as to why they would adopt such an expensive and complex solution to ease a service task (i.e. front wheel removal) which isn't really done all that often and isn't difficult in the first place. Oh well....inscrutable Orientals I guess....
 
MaxPete said:
I am just puzzled as to why they would adopt such an expensive and complex solution to ease a service task (i.e. front wheel removal) which isn't really done all that often and isn't difficult in the first place. Oh well....inscrutable Orientals I guess....
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Pete
My guess is they didn't know any better. This was there first disk brake bike (I think). I'm guessing in engineering sometimes time proves what works and what is necessary and what isn't.
 
GLJ said:
Not a big notch. Don't see it from the left. But the notch size will depend on the shock. I do remember the BM shocks were a very good improvement from the factory shocks. If your replacements don't have the springs all the way to the bottom of the shock you may not have to do anything.
View attachment 134733
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Thanks GLJ!
 
Yes, I was going to mention that offset bottom eye. The lower mounted springs are an issue on many aftermarket shocks. Adding to the clearance problem is the fact that most aftermarket shocks have larger diameter bodies too. The PS Series 12 shocks 650Central sells come with the offset bottom eye. My buddy just got some and they look really nice. I'll let you know if they present any mounting issues. We'll be combining them with a TX750 swingarm upgrade on his '80 Special II.

A chain guard clearance issue we may encounter though has more to do with the angle that the shocks mount at. The 650 chain guard won't mount on the 750 swingarm without modding. If we choose to use the 750 guard, it is notched out for more upright "Standard" mounted shocks.
 
Sometimes little things can be a real pain. I had ordered new dampers for the gauges and ignition switch. Old ones could have been reused, new will be an improvement. In looking over the mounting hardware for the switch I noticed the washers that I gave Mailman grief over didn't look so hot. Ordered new OEM washers from Partzilla. Everything came in. Looked things over and the new washers were perfectly sized except they are black. That wasn't going to work. Trip to Menards picked up some stainless fender washers, little lathe time and made some washers.
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A guy almost needs 3 hands to get the gauges installed. I cringed at doing this, was very careful.
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Nice thing about Mailman's thread is it gets me thinking about things I need to do. After reading about his front brake light switch and his very good workaround I needed to decide what I was going to do. I chose to retain a switch on the MC. I had to do a little work to it.
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Wasn't to bad to do, just took some time. I transferring my old lever and bolt to the new MC I found the threaded bushing was worn out.
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EBay is amazing. Not only got a new bushing but also a new bolt and lever. It all fits.
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Wanted to use the new adjusting screw that came with the new MC but it appears Yamaha used a JIS fine thread M6-.75. Not very common now. If I need more adjustment than the screw has I can always put a role pin in the lever that came with the new MC and use it. Kind of fun tinkering with old bikes.
 
Very nice work , fitting your original brake light switch to your new M/C. I had already broken down my switch and cleaned the contacts , then went to mount it, only to realize it wouldn’t fit without machining my M/C. Bummer!
I had even considered just trying to do something similar to what you did with just my hand drill, but it was the clutch pivot bolt that threw me, because the hole is stepped right?

Also I can relate to your clamping to compress those mounting rubbers, yikes I really struggled with getting those gauges on.

Looking good man! :thumbsup:
 
Mailman said:
I had even considered just trying to do something similar to what you did with just my hand drill, but it was the clutch pivot bolt that threw me, because the hole is stepped right?
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I'm sorry I don't understand. "Clutch pivot bolt" ?
 
Sorry, poor choice of words. The bolt for the clutch lever, I couldn’t think of the correct term.
 
I think I know what you mean. The word clutch threw me. I'll post a couple of pics later on what I had to do.
 
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Yes a step has to be machined on the bottom side of the perch for the switch body to set in. You also have to drill a hole for the plastic pin on the switch to set in. To make the pin hole I made a crude jig to guide the drill bit. Needed to do that because you are drilling at an angle compared to the housing.
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For the pivot bolt hole I drilled it with a 3/8s drill bit to the depth I wanted. This does not leave a flat bottom hole. I then used a 3/8s end mill to mill the bottom flat. If I had a real mill and better clamps I would have skipped using a drill bit first. If a guy had a real steady hand you might be able to do this with a hand drill. Fortunately for me I have a cheap drill press.
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