ProSimex
XS650 Addict
I think your going to wanna seriously reinforce that swingarm dude, otherwise cool idea
-
Enjoy XS650.com? Consider making a donation to help support the site.
XS650.com receives a small share of sales from some links on this page, but direct donations have a much greater impact on keeping this site going.
osteoderm
out of the box
Absolutely! That's what the boxes of steel that showed up this week are for...
I really like what you have done.
So how are you going to build the tank?
I did about the same thing. but with plywood instead of cardboard. The foam seems to expand for a year or so I have had to reshape a couple of times. I have been working with Aluminum sheet. Makes me really appreciate those craftsmen that can do that well.
If you are doing it in sheet metal here is a magical vid of a tank being made. I have watched it a hundred times. Still am amazed.
So how are you going to build the tank?
I did about the same thing. but with plywood instead of cardboard. The foam seems to expand for a year or so I have had to reshape a couple of times. I have been working with Aluminum sheet. Makes me really appreciate those craftsmen that can do that well.
If you are doing it in sheet metal here is a magical vid of a tank being made. I have watched it a hundred times. Still am amazed.
osteoderm
out of the box
Not entirely sure yet. Once I have a male plug I like, I'll pull a mold from it. From there, I could make male or female forms for aluminium forming, or make a lost-foam male plug for a carbon tank. Sheet-metal work is not my strong suit, but I'm completely comfortable with epoxy composites.
It's still entirely possible that I'll find something pre-made that I like better than all this extra work!
jchrisk1
XS650 Junkie
You can use foam board insulation to make your molds with. The pink or blue stuff. It is much easier to work with and shape. Just glue it together with 3M spray adhesive and start carving. And it sands real nice.
Scgoobertn
XS650 Enthusiast
- Messages
- 68
- Reaction score
- 0
- Points
- 6
Your idea for the Capacitor is awesome!!
osteoderm
out of the box
Oh, I'll be the first to agree that the spray foam is crap to work with! It's my boatbuilder's habit to start with formers/stringers to build the 3D shape up out of planes, rather than carve down a large block of foam.
The nice part about working with sheet foam as you've suggested is that it's simple to mirror: instead of gluing the sheets together (typically with horizontal seams), you temporarily tack the pices together with vertical seams. This way, once you have a tank side shapes as you like, you can dissect the slabs and trace each one onto duplicates for the other side.
For male molds, it's important to be aware that resins and solvents attack different foams in different ways, so it's important to use a foam that is stable when you overmold it, but melts out cleanly when you need it to post-cure.
osteoderm
out of the box
Progressing on several fronts this week, mainly measuring, designing, and ordering metal bits for the clutch and swingarm links. The most satisfying progess was with the tank mock-up:
Bondo'd...
Carved up...
Sanding and filling...
Just working the left side, trying to find the shape I'm imagining. Will mirror it when the shape is there...
The tunnel shape/size/angle is just approximate. Sitting a little high right now, hung up on the motor mounts.
I think I just about have it like I want it!
Bondo'd...
Carved up...
Sanding and filling...
Just working the left side, trying to find the shape I'm imagining. Will mirror it when the shape is there...
The tunnel shape/size/angle is just approximate. Sitting a little high right now, hung up on the motor mounts.
I think I just about have it like I want it!
Patches
XS650 Junkie
This Royal Enfield tank came to mind when I saw the profile of yours, Hope this helps:
http://www.ebay.com/itm/Royal-Enfie...ies&vxp=mtr&hash=item4842e2b765#ht_499wt_1364
Not quite as sharp of a line around the side but it's very, very close.... A little bit of kitty hair any you could be in business........
http://www.ebay.com/itm/Royal-Enfie...ies&vxp=mtr&hash=item4842e2b765#ht_499wt_1364
Not quite as sharp of a line around the side but it's very, very close.... A little bit of kitty hair any you could be in business........
pregrid
XS650 Guru
excellent work,,,,,,,,
osteoderm
out of the box
Mounted the hydraulic clutch slave to the sidecover today.
In mockup, the two forward-most mounting tabs just clear the radius at the base of the alternator cover area when the top of the slave is parallel to the bottom edge of the case. In other words, there's only one ideal rotation to place the slave at, and it just happens to be the best-looking. Weird coincidence? I'll take it!
Transfer punches are your friends.
Pilot holes are also your friends... especially going through all the weird webbing inside the cover!
6mmx1.00 tapped. Plenty of thread.
Piston retainer dropped into place. Tapered nylon washers to make up the tiny gap between the flat slave and curved sidecover. Would have preferred to have this be a flat metal-to-metal seat, but the retainer in the adjuster opening is fully locating and backing the slave, so these washers are really just gap-fillers. As long as it works, I'll be happy to not machine the sidecover! The black Sharpie on the retainer is a remnant of the fitting process.
Bolted down. 6mmx200mm Stainless. Would have used buttonheads, but the tabs on the slave are recessed for the allens... and like I need another thing to file/sand/machine...
On the inside, the forward two bolts grab plenty more material. Except for the tapped holes, there's no change to the sidecover, and the stock cable actuator can go back in if need be.
Not as low-profile as the Magna swap, but more tidy. No discernible shift-lever interference.
The obligatory glamour shot alongside the master cylinder!
In mockup, the two forward-most mounting tabs just clear the radius at the base of the alternator cover area when the top of the slave is parallel to the bottom edge of the case. In other words, there's only one ideal rotation to place the slave at, and it just happens to be the best-looking. Weird coincidence? I'll take it!
Transfer punches are your friends.
Pilot holes are also your friends... especially going through all the weird webbing inside the cover!
6mmx1.00 tapped. Plenty of thread.
Piston retainer dropped into place. Tapered nylon washers to make up the tiny gap between the flat slave and curved sidecover. Would have preferred to have this be a flat metal-to-metal seat, but the retainer in the adjuster opening is fully locating and backing the slave, so these washers are really just gap-fillers. As long as it works, I'll be happy to not machine the sidecover! The black Sharpie on the retainer is a remnant of the fitting process.
Bolted down. 6mmx200mm Stainless. Would have used buttonheads, but the tabs on the slave are recessed for the allens... and like I need another thing to file/sand/machine...
On the inside, the forward two bolts grab plenty more material. Except for the tapped holes, there's no change to the sidecover, and the stock cable actuator can go back in if need be.
Not as low-profile as the Magna swap, but more tidy. No discernible shift-lever interference.
The obligatory glamour shot alongside the master cylinder!
Following closely. I have a near identical slave and I'm happy to have you do the pioneering. Thanks! Now for your custom push rod build..........
osteoderm
out of the box
Glad to be able to share my progress!
The pushrod is going to be very straight-forward; the working face of the hydro piston is a sealed grease-filled cup that receives the outboard end of the pushrod. The seal, cup, and bearing face all accept the stock 8mm pushrod, and the piston is spring-loaded/self-adjusting.
So far, it looks like all I'll need is a slightly longer 8mm rod, with no special machining, except a slight radius on the outboard end.
osteoderm
out of the box
Excellent progress today with the swingarm! First, a little background... I am converting to a monoshock.
Most of the (very few) XS monoshock conversions I've seen online are of the direct-acting high-mounted type (exemplified by Chad Going's excellent example). For my build I wanted to keep the suspension components low and stealthy. There's a few direct-acting low-mount monoshock conversions out there, but that arrangement puts a tremendous strain on the shock(s); the leverage is so great that people use two shocks and/or have the preload wound to the nuts.
Then there's the indirect-acting low-mount types, with some form of progressive linkage, some form of which can be found on most all modern monoshock bikes. I've seen such conversions on Yamaha RD's, and one notable XS650. In all these examples (as least that I've seen), they're using a custom frame and/or modern deep-section aluminium swingarm and/or <16" wheels.
For my build, I want to keep both the spoked 18" rear wheel, a period-looking round-section steel swingarm, and an otherwise stock-appearing frame. Yeah, I know, sounds like a disaster. Well, what the heck, nothing ventured, nothing gained, right?
Most of the (very few) XS monoshock conversions I've seen online are of the direct-acting high-mounted type (exemplified by Chad Going's excellent example). For my build I wanted to keep the suspension components low and stealthy. There's a few direct-acting low-mount monoshock conversions out there, but that arrangement puts a tremendous strain on the shock(s); the leverage is so great that people use two shocks and/or have the preload wound to the nuts.
Then there's the indirect-acting low-mount types, with some form of progressive linkage, some form of which can be found on most all modern monoshock bikes. I've seen such conversions on Yamaha RD's, and one notable XS650. In all these examples (as least that I've seen), they're using a custom frame and/or modern deep-section aluminium swingarm and/or <16" wheels.
For my build, I want to keep both the spoked 18" rear wheel, a period-looking round-section steel swingarm, and an otherwise stock-appearing frame. Yeah, I know, sounds like a disaster. Well, what the heck, nothing ventured, nothing gained, right?
osteoderm
out of the box
First, I had to find the "right" monoshock and linkage. After much hunting, I settled on an '08 Kawasaki ZX6R shock and linkage. The shock reservoir is compact and horizontal for maximum clearance and stealth, while the style of link stays away from the tire. Also, the general arrangement allows the final ride height to be set independently from the shock height and preload.
My first mock-up with the stock swingarm shows how tight all the components are:
Notice that the axle is fully rearward, that the rocker link is pushed too far back, and that the shock is being held back by the swingarm gusset.
By my third or fourth mock-up, things are much improved:
Now the axle is fully forward, the rocker link is dropped into a nice neutral position, and the shock is much closer to the backbone.
All the clearance came out of the swingarm gusset:
I know what you're thinking. That gusset is a huge part of the swingarm, and I can't just whack it out without paying a penalty! Indeed, I'll have to beef-up the swingarm some other way to make up for it...
My first mock-up with the stock swingarm shows how tight all the components are:
Notice that the axle is fully rearward, that the rocker link is pushed too far back, and that the shock is being held back by the swingarm gusset.
By my third or fourth mock-up, things are much improved:
Now the axle is fully forward, the rocker link is dropped into a nice neutral position, and the shock is much closer to the backbone.
All the clearance came out of the swingarm gusset:
I know what you're thinking.
That gusset is a huge part of the swingarm, and I can't just whack it out without paying a penalty! Indeed, I'll have to beef-up the swingarm some other way to make up for it...
Last edited:
pregrid
XS650 Guru
Great work, interesting thinking, keep it up!
osteoderm
out of the box
The gusset added both strength and stiffness to the swingarm. If I can't have the usual gusset in the usual place, I'll have to get that strength and stiffness back some other way.
The first way to reclaim it is the bare swingarm itself. In this case, I'm using a 1973 TX750 swingarm; it's a little larger, a little longer, but is otherwise a no-brainer direct bolt-on to the '74 TX650 frame. The increased tubing size alone goes a long way towards reclaiming the lost strength/stiffness. The two rules of thumb I'm following here are:
The diameter difference between the 650 and 750 swingarm is approximately k=1.2. It's harder to measure the material thickness, but I'm comfortable in figuring that the TX750 swingarm is 70%-100% stiffer, and 40%-70% stronger. As such, the change in swingarm makes up for a portion of the losses incurred by the factory gusset removal.
I am, in any case, not particularly worried about strength. Steel is a tough and forgiving material with a graceful failure mode. Stiffness is the worry here; most of the usual swingarm bracing I've seen seems more concerned with stiffness than strength.
I'd really like to keep the "bare swingarm" look, but am willing to accept additional bracing if required. Still, I'll cross that bridge when I come to it, and first address the basics...
The first way to reclaim it is the bare swingarm itself. In this case, I'm using a 1973 TX750 swingarm; it's a little larger, a little longer, but is otherwise a no-brainer direct bolt-on to the '74 TX650 frame. The increased tubing size alone goes a long way towards reclaiming the lost strength/stiffness. The two rules of thumb I'm following here are:
- If both the diameter and wall thickness are multiplied by some number - call it k -then the rigidity increases by a factor of k^4 and the strength by a factor of k^3. (Meanwhile the weight for a given length increases by a factor of k^2.)
- If the diameter is multiplied by k but the wall thickness is not changed, the rigidity increases by a factor of approximately k^3 and the strength by a factor of approximately k^2 . (Weight increases by a factor of approximately k.)
- Nuthin' too strong ever broke.
The diameter difference between the 650 and 750 swingarm is approximately k=1.2. It's harder to measure the material thickness, but I'm comfortable in figuring that the TX750 swingarm is 70%-100% stiffer, and 40%-70% stronger. As such, the change in swingarm makes up for a portion of the losses incurred by the factory gusset removal.
I am, in any case, not particularly worried about strength. Steel is a tough and forgiving material with a graceful failure mode. Stiffness is the worry here; most of the usual swingarm bracing I've seen seems more concerned with stiffness than strength.
I'd really like to keep the "bare swingarm" look, but am willing to accept additional bracing if required. Still, I'll cross that bridge when I come to it, and first address the basics...
osteoderm
out of the box
Most of the gains in going to the TX750 swingarm are in stiffness. In particular, tube stiffness. The torsional (twisting) rigidity of the tubes themselves contributes directly to the torsional rigidity of the whole swingarm. However, it would seem to have a less-marked effect on horizontal wracking and flexural (bending) stiffness.
The dogbone links that join the swingarm to the rocker link should act to increase torsional rigidity: when one side leg of the swingarm moves up or down, the other side is forced to follow. Unfortunately, the mid-span attachment point of the dogbones to the swingarm (approximately 4.75" behind the main pivot shaft) puts a large flexural load on the swingarm.
Looking at all this, I'm going to address flexural stiffness first, regain as much gusset as possible (given the spring placement) to address horizontal wracking, then move to additional bracing if required.
6' of 1.5" mild steel square tube...
WTF? Cut off the wrong half, left the seam on the right half... this is why I bought 6' to make a 28" piece!
Just a double-check... yup, cutting it the right way this time
Quick 2x6 scrap cut to make a bending form.
Trial fit. Needs more massaging yet, and to have the channel opened up a little bit to more fully nest against the round tube.
The new gusset will run full-length for added vertical flexural stiffness and strength.
The dogbone links that join the swingarm to the rocker link should act to increase torsional rigidity: when one side leg of the swingarm moves up or down, the other side is forced to follow. Unfortunately, the mid-span attachment point of the dogbones to the swingarm (approximately 4.75" behind the main pivot shaft) puts a large flexural load on the swingarm.
Looking at all this, I'm going to address flexural stiffness first, regain as much gusset as possible (given the spring placement) to address horizontal wracking, then move to additional bracing if required.
6' of 1.5" mild steel square tube...
WTF? Cut off the wrong half, left the seam on the right half... this is why I bought 6' to make a 28" piece!
Just a double-check... yup, cutting it the right way this time
Quick 2x6 scrap cut to make a bending form.
Trial fit. Needs more massaging yet, and to have the channel opened up a little bit to more fully nest against the round tube.
The new gusset will run full-length for added vertical flexural stiffness and strength.
osteoderm
out of the box
While I'm comfortable with most of the basic fabrication, one area I'm completely lacking in is welding. Sure, I can make as much a mess as anybody with a stick or a MIG gun, but I'm not going to trust my welding "skills" on something like this swingarm.
If you want to save a few bucks and are willing to do all your own fabbing and fitting, then it's a huge advantage to be able to work with a skilled welder who is okay with your prep. I've been very fortunate to work with Teak Ackman at Seven Star Marine Engineering here in Newport RI. As well as being a gearhead and motorcyclist, his bread-and-butter is making up high-end custom fittings for the yachting industry.
I run my whacky ideas past him first, agree on a method, then come back once I have a round of parts ready for welding.
Just a few neat TIG tacks so I can get on with the next piece.
Templating the "taco".
First side of .080" sheet cut and clamped, ready to start the bend.
Wrapped around with the second side cut, fit, and ready to weld.
Not as large and elegant as the stock gusset, but as much as I can fit into the space I have left, and as well-fitting as I can make it. Can't forget that wire brushing to keep the welder happy!
If you want to save a few bucks and are willing to do all your own fabbing and fitting, then it's a huge advantage to be able to work with a skilled welder who is okay with your prep. I've been very fortunate to work with Teak Ackman at Seven Star Marine Engineering here in Newport RI. As well as being a gearhead and motorcyclist, his bread-and-butter is making up high-end custom fittings for the yachting industry.
I run my whacky ideas past him first, agree on a method, then come back once I have a round of parts ready for welding.
Just a few neat TIG tacks so I can get on with the next piece.
Templating the "taco".
First side of .080" sheet cut and clamped, ready to start the bend.
Wrapped around with the second side cut, fit, and ready to weld.
Not as large and elegant as the stock gusset, but as much as I can fit into the space I have left, and as well-fitting as I can make it. Can't forget that wire brushing to keep the welder happy!
