Good Heart, Bad Intentions: another build thread

What do you suppose engine heat and road grime will do to the clear tube?

When I first had this idea, I had no intention of a clear tube. I was originally thinking of using aluminium pipe or tubing, but the available dimensions were either too expensive (for quick and dirty prototyping) and/or would require further machining to fit.

The polycarbonate tube is 1/8" wall thickness, with a 200F rated operating temp (290+ F "softening point"), so I'm not particularly worried about strength.

The clear aspect is neat, and lets me see how it is coming together, but I'll probably paint or wrap it in the end. If it breaks or ends up looking like crap, it's not a impossible fix.
 
"What if?..." is a great starting place, isn't it?

2011-11-12_08-54-44_91.jpg

2011-11-12_08-50-57_269.jpg

2011-11-12_08-57-34_749.jpg


All standard so far... Now here's where I start to screw things up a bit:

2011-11-12_09-14-18_883.jpg

2011-11-12_09-13-53_206.jpg

2011-11-12_09-13-23_231.jpg
 
The clutch slave is a Rotax 259500 from a 2007 Aprilia RSV1000. It didn't take long to find this slave cylinder, but it took me ages to figure out that it was the one I was looking for. The important part is the external retainer that keeps the piston from over-travelling:

2011-11-12_09-21-56_630.jpg


I don't need or want the extra height of the retainer and "legs", but not only are they easy to cut off...

2011-11-12_09-45-28_973.jpg


...but also, the remaining part of the retainer is mind-blowingly close to the diameter and depth of the sock sidecover clutch adjuster opening:

2011-11-12_11-09-11_902.jpg


With some fairly quick work with a few files and a little emery paper, the retainer is ready to go. With a lathe handy, this would take just a couple quick passes to perfection. The only alteration to the stock sidecover at this point has been to de-burr the feather edge that the stock chrome adjuster cover snaps into.

2011-11-12_11-51-26_167.jpg


The retainer protrudes into the sidecover less than the stock assembly, so I anticipate using a longer pushrod.

2011-11-12_11-51-42_834.jpg


The height of the widest portion of the retainer is almost exactly the same as the depth of the adjuster opening.

2011-11-12_12-14-51_537.jpg

2011-11-12_12-15-04_275.jpg


Still a few loose ends to figure out, but I'm very encouraged so far!
 
If my other ideas are "out of the box", what is this one out of?

2011-11-09_13-37-23_707.jpg


This is just my second or third mock-up... swingarm bracing, linkage and shock mounting tabs, etc., still to come. However, I did get two boxes of steel from McMaster Carr today! (That UPS guy is better than Santa, I swear).
 
Uh-oh, I did it again... Took a simple idea and managed to make it infinitely more complex.

First we have the stock tank. Actually, it's a '76 tank in '74 colors. I don't mind the stock tank shape, but it's just too dang big.
2011-11-12_14-09-06_662.jpg


After looking at a few thousand tanks online, I found this oddball on eBay, listed as a '70's Yamaha enduro tank:
2011-11-12_14-10-54_285.jpg

Kinda compelling shape: just large enough for reasonable fuel capacity, small enough to fit the backbone and show off the engine head a bit more, deep enough tunnel to hide the ugly head gusset area.

2011-11-12_14-11-05_516.jpg

Interesting angles, but that tail end, uhg! Too square, even for my oddball taste. I cut the old mounting flanges down, and sanded it some, but things never much imprved. i did, however, find a factory decal under the lurid rattlecan paint, and it sure isn't a Yamaha tank (no surprise). AMF Harley, probably an Aermacchi 250. Think I saw one of these on an XS before, maybe somewhere on this site. Anyways, neat tank, interesting shape, but not quite worth the effort.
 
With no luck finding or buying the tank I keep seeing behind my eyelids, I was struck by the urge to shape a mockup of what (I think) I want:
2011-11-13_09-53-33_69.jpg

High, arching profile, more like a Triumph tank...
2011-11-13_09-53-46_336.jpg

Angular cross-section, high shoulders, narrower profile. I want 2.5Gal+ of fuel, but also want to be able to see the cam covers past the tank from the riding position.
2011-11-13_10-34-20_893.jpg

Quick and dirty prototyping at its best. Focusing on the left side, the right side much rougher, just quick tracings of the left-side pieces.
2011-11-13_11-12-15_16.jpg

Checking the tail profile with a few swipes of tape. From above, the front of the tank shows improved hand clearance for clip-ons or clubmans. So far, so good.
2011-11-13_11-21-27_708.jpg

Formers and stringers in place on the planes of widest axis. Now a few diagonals to define the pickier compound curves. Okay, enough with the cardboard! Used up alost the whole box that the last tank arrived in.
2011-11-13_12-29-54_933.jpg

Foam On! Seriously, at this moment, I was doubting my sanity.
2011-11-13_15-32-35_19.jpg

Not quite patient enough to wait for the foam to completely cure before I started shaving; still a little goopy in the middle. Anyways, the idea is to just shave away at the foam until the edges of the cardboard start to show.
I'll take more pictures once I get my hands unstickied... :)
 
Grabbed a couple more pics of the cut-down clutch piston retainer this morning.
2011-11-15_07-54-45_501.jpg

2011-11-15_07-54-56_505.jpg

If I ever have cause to do this again, I'll certainly use a lathe instead of the "file then fit then file some more". Either way, it's not much material to remove.
 
Crazy crazy week here, but did manage to sneak away from life for an hour and shave the foam tank down a bit. I sectioned the tunnel area as well, just to tighten the whole shape up a bit.

2011-11-15_07-55-13_744.jpg


The tank is sitting high in this shot; the narrowed tunnel fits the backbone, but not the top motor mounts. Hmm, shape the tank to fit, modify the mounts, or both? I swear, I'm a sucker for punishment.
 
In R/C planes there is quite a bit of vibration we wrap batteries in foamrubber. at your local hobbie shop you can find some. It is not just cheap foam crap too. it will last and it is made just for keeping batteries safe from vibration. just a thought.
 
In R/C planes there is quite a bit of vibration we wrap batteries in foamrubber. at your local hobbie shop you can find some. It is not just cheap foam crap too. it will last and it is made just for keeping batteries safe from vibration. just a thought.

Good idea. I have a box of small offcuts from a custom hotrod seat I did last year, all different densities of memory foam. McMaster Carr also has neoprene cord for making custom o-rings which looks like an interesting material to try.
 
Back
Top