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A pendulum?

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Miata UBJ: ES-2074R('70s maz pickup)
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The driver is the pendulum. Advantage: driver has balance system built in, a brain and muscle control, all of which, with some training can operate subconsciously. Like riding a bike.

The added chain drive thing is getting better. A Virago guy tried to convince me not to mess with the ratios, that high revs at cruise is OK. So I'll compromise, and add two pairs of sprockets, a 1:1 set to keep the original drive ratios, and a second pair in case I want to try some overdrive. One chain at a time.

The trick will be re-doing the drive yoke to take a sprocket but I have that worked out fairly well with a minimum of added stuff. Since the Virago drive spline doesn't match any available sprockets, I have to cut & grind the yokes, the drive and the driven ones that fit the shaft splines, to hold a pair of sprockets each. Ebay is my friend; amazing how many odd bits one can find there.

Moving this little topic from Suppliers to here.

I tried sandwiching a thin (1/8") piece of styrofoam between epoxy glass layers, both flat and in a bowl-shape to see how it would conform to a curved mold.

First the bowl - I pressed the foam over the mold first with some heat, trying to get it to conform without wrinkles. Then I laid one lightweight sheet of glass over the mold and wet it down good with epoxy, pushed on the foam bowl-shaped piece with its mylar reflective sheet still attached on the outside, and added another poorly fitting bowl over that in an effort to compress the layers together. An hour of cure time at 200 deg.

Then peel off the mylar, add another layer of glass-epoxy, cook it again. Done, but it had bubbles; a vacuum bag probably would work better to get everything to lay tight together and bond without voids. The foam sheet should oughta be cut & fitted better; it compresses to fit the compound curve but not enough. More heat would help but after a certain temp the styrene melts into goo. Not too bad for a first try though; it is plenty stiff for a body part, needs another layer of glass to keep it from dimpling when poked. Nice and light. BTW, the mylar layer just happens to be on my sample; it has no purpose here.

Then the flat piece - way easier. I used a double layer of foam (glued together) and heavier glass since the flat is for the floor. Pressing between two flat sheets works real nice. Must add more glass for the same dimple problem as above, and for better stiffness in a flat span.

On the chain drive setup I mentioned earlier: It may get easier to do; I'm looking at another 920 Virago, 1981 chain drive rather than shaft drive. If I get that bike I can turn the engine sideways a la Motoguzzi, push it further forward and to the right. Drive sprocket now is on the front of the engine for correct rotation, connected by chain to the (longer now) jackshaft near center spine.

This gets me back to my original plan, a vee-twin with cylinders sticking out sideways. AND I get to use a running bike as a donor instead of a used-up junker, which helps a lot with my peace of mind, etc. (Way less frustration?) Plus it eliminates the job of mounting a sprocket to a u-joint yoke.

Right now I'm learning all about how to fix the (bad) Virago starter; after 25 years they get beat up pretty bad, grind a lot.

OK I bit the bullet and snagged that chain drive Virago on ebay. I'll have a running legal bike to ride for awhile before it gets converted to three wheels. Bad starter but I swear I'm gonna engineer a fix for that problem.

Isn't one of the inexpensive Harley starters a bolt-in replacement? A friend had a Virago and mentioned something about it several years ago.

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I hadn't heard that. Virago starter has planetary gears at the end of the motor, then a little jackshaft holding the engagement gear that moves to mesh with the ring gear. I'd be plumb flabbergasted if a Harley starter would bolt in and replace all that stuff. The weakness in in the design of the intermediate shaft & gears, where they put a binding spring around the gear to keep it from rotating while it is being pushed into engagement. So the spring can be too loose or too tight, and either way it drags on the starter as it tries to crank.

It might be something specific to a certain generation of the Virago? All I remember was him saying he popped in a used Harley starter for about $35 and it was fairly well known fix at the time. Who knows, lol.

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Hey! I had one of those brilliant ideas after I got the "new" bike home. The one with a bad starter. It is a perpetual problem with Viragos of that era, around 1980 to 85.

Since few here will be familiar with that setup, or won't care much, I won't go into the details. A spring shaped like a claw grips the starter gear in a V-groove to keep it from turning while it engages. The spring/groove wears down and lets the gear spin more than it should, so it grinds instead of engaging. Yamaha actually places a magnet directly under the gear to catch all the chips from starter gear grinding!

The std fix is to replace spring and gear every few thousand miles. I will make a new spring, and install a finger fixed to the case, which releases the spring grip as soon as the gear is engaged. This allows starter to spin without constant friction, and eliminates most of that wear.

I'll report success after its done. Or failure. If it works I'm sure many old Virago owners will be interested in trying a new fix.

My problem now, other than the starter, is that the '81 chain drive bike is as perfect as it can get for its age, and is worth a lot more as is (with starter fixed) than for parts. I really hate to trash it for the engine only, so it may end up that I sell it and either go back to the shaft-drive motor, or find another chain-drive engine or a ragged parts bike. Is hard to decide, but the decision will wait til both engines are running; each can prove itself or not.

Did you know that side windows from an early-80s LUV pickup are a perfect fit for Jonny's new 3-wheeler? There are really very few production glass pieces of the right size, shape and curvature that would fit my rough outline; most are too tall.

I got both doors from the LUV so I can try to cram the winding mechanism, and glass, into a one-inch thick flat door. I may have to thicken it some, but inside people room is too important to waste on door volume.

All side glass is removable, right? Not this one. It looks to me like the door was welded together around the window glass! Whether that is true or not, I will chop away the steel until I find access.

I spent the weekend taking care of little mechanisms that connect one part to another. For me these are time-consuming and fun. Like the crank at the front of the frame, connecting it to the tilting cylinder. I disassembled a crapped-out 20" mower, put the crankshaft in the lathe to cut off the part that turns the blade; that will weld into the end of a larger tube extension of the center spine, rotating on two bearings in the center of the front axle. I cut the blade off, ground it down, and bored a hole near one end. Now I have a very sturdy tilting crank, designed and tested over many years by the mower people, and I did mostly cutting and grinding; no serious machine work.

The cylinder-to-crank fitting started as a 3/4 steel round. Turned, drilled, tapped, slotted. The pin is a 3/8 shoulder bolt. Failure is highly unlikely; that assembly is real tough.

The LUV side glass turned out to be removable after all! I did pry the outer door panel out to make a window-thickness gap, but it came out pretty easily.

I have to thicken some of the door now so I can fit in the lifting mechanism along with the glass. It adds some weight, but it sure works better than a straight manual lift. Fiddling with it now to get both the 2 doors and too-wide seats into my 48 inch width limit. I may widen it some where the seats are, and modify the upholstery to fit. I reckon that once I get into it some evening, re-contouring some cushions won't be all that difficult.

The curved glass has a 100 inch radius, so it WILL fit into a slim door, and curve inward by 2 or 3 inches at the top when cranked up; door gets less slim when the cranking stuff is added. (I could use a stretchy inner panel that bulges only where necessary.)

I finally got around to opening up the rusty junk-yard VW front axle to see what has to be replaced/rebuilt. I was pleased to see that the drums are in fine shape, bearings perfect, steering box pretty good, even the brake linings are plenty thick.

That leaves cruddy master cylinder to be honed out and rebuilt, some new brake lines, one or two slave rebuild kits, and a bit of welding. The hard part will be cleaning it all up and painting it to look decent.

I'm tempted to pay $35 for a set of new lines just because they will have nuts and flares already done. I'll use just three of them, one for each wheel; the flex hoses in front are already there and in good shape.

2nd question: who among us knows how to eliminate play in the steering box, or if it is even possible. It is a worm & pinion, I know that much, and there is an adjustment screw with a lock nut on top of the housing. Conceptually, I don't see how a worn worm can be fixed to eliminate play, but I've been surprised before. Maybe adding a spring somehow to hold the worm against the pinion in one direction? The play isn't too bad but I don't want it there if I can get rid of it.

The cruddy master cylinder is scrap "nobody rebuilds those old thangs any more" but new ones are available, and shoes, and slave cylinders.

My question on removing play from the steering box was answered in a good down-home VW fixit site: there are two adjustments possible on the box, one for the worm and another for the pinion. I haven't tried it yet.

Fuel tank. Now that the VW frame head is sitting on the floor in my little shop, I've been able to work in a fuel tank, fill otherwise empty space. Originally I had figured 5 gallons is plenty but then since I have the volume available, 7 1/2 gal might provide 300 mile range, so why not. Yes the tank is right up front, about a foot behind the forward end of the nose cone, but it is behind the parallel spring tubes and formed in around the frame head. All that metal is too heavy already for this light car, so it might as well double as armor. In defense of putting the fuel up front: 1) VW of that era did it too, and 2) I want to get more of the weight on the front wheels.

I'll carve a foam core the right shape to fit around the center frame, in pieces so it can be removed, and then wrap it with epoxy glass, leaving the top open in the first stage so the foam can come out, then adding a final top piece. Will probably use a piece of hardware cloth under the top laminate to keep it from sagging into the tank, plus mold in a filler cap and an exit tube.

The lower part of the tank (L-shape) will slip in under the tie rods behind the axle, then extend eleven inches up from the floor behind that. 28 inches end-to-end between the front wheels. A centered chrome-plated filler cap just forward of the bonnet might look OK. I'm leaving plenty space for a guided stream of cooling air from the grill to over the motor on the right of centerline, then out through louvers in the bonnet. Floor under engine and everywhere else will be sealed.

Asking for opinions: Would the vee-twin look better exposed on one side or covered with a louvered bonnet Bugatti-style? The left side will have a bonnet in any case, so in the interest of symmetry I think most locost votes would be to cover the motor?