Rust 'bubbles' show problem

You will recall that when the sheet metal was media blasted, several areas of rust-through were revealed. Here you can see one of four areas on the sides of the front fender that show rust through from underneath.

view from underside - spot-welded braces

Here is the cause. Puch used two metal braces – ‘U’ shaped channel-sections spot welded to the underside of the fender to stiffen it. Since these are channel-sections, there are spaces between them and the metal of the fender skin which can trap moisture. You can see that Puch have provided some level of drainage by leaving openings at the ends. Unfortunately, this proved completely ineffective, since the underside of a fender is naturally bombarded with moisture and dirt throughout its life. It is the function of a fender, after all! In this case, moisture has been trapped in these spaces and has gradually eaten away at both fender and brace from the inside out. We have little choice but do major (and extremely ugly) surgery.

using an angle grinder to cut out the rust.

This is what I’m talking about. Tempting as it might be to just gloss over this area with some filler, it wouldn’t be a true restoration and the problem would quickly reassert itself. So nothing for it but to get ugly with a grinder and cut out the compromised sheet metal over the braces. I made four slots, two per side over the two braces.

removing dirt packed into the space

…And here is the reason for the rust. Puch’s drainage might have worked, but being a fender, these spaces filed up with dirt, forming a kind of sponge that soaked up and held water, which in turn rusted through the steel. To repair this properly, I am going to have to clean out the dirt, wire brush these gaps to remove as much rust as possible, treat the area with rust converter, weld in patches and then saturate these spaces with the same anti-corrosion paint I’m using on the rest of the bike. Ugh. Stay tuned!

Primer reveals 4-5 depressions

Sometimes the only way to see all  imperfections is to apply a coat of primer. Last post we followed the Puch tank from rough to prime.  Today, we can see that the job is not quite done.  Look at the top, tail section of this tank.  Can you se the 3-4 elongated depressions?  One wonders about the history of old bikes like this.  How did this odd damage occur? Or is this how it came from the factory, like the many obvious spot welds I have found around the bike?  The Allstate versions were price-concious and ‘fit & finish’ in 1962 was not to the meticulous standards of the present day.  In the interests of authenticity I want to preserve the manufacturing ‘flaws’ as much as possible; however since the tank is the focal point of any bike, this particular  flaw (original or not) must be corrected!

After block sanding

Here’s where a block sander comes in handy. The shiny ‘fingers’ are the high spots where the sanding block has removed the primer and old paint. Te lines of black in between are the low spots we need to fix.

hammer work reduces the bumps

Of course, you could just slather body filler over this area, but the final contour would probably not be correct for the tank, because the high spots are probably higher than they should be.  Instead, we are going to use a hard rubber mallet to gently and carefully, knock them down.  If you do this correctly, you can ‘massage’ the metal to a less pronounced deformation, greatly minimizing the amount of filler to just a thin ‘skim’ coat.

Note the seam in the centre of the tank – the is the joint between the two tanks – gasoline and oil.  This is a high spot that will form the reference point, since it can’t be deformed .  The contour must slope from the centre outward.

first application of filler

Now we can start to apply that skim coat of filler. This is actually the first of two applications. This one was not quite enough, the areas on the right and left are still ‘proud’ (high) and a second thin application was required to get just the right curvature.  I like to use a body metal file to remove the excess and roughly shape the filler as it hardens. Then when it is really hard, I use the block sander with 400 grit wet-or-dry sandpaper to shape the final contour. Remember, if you can feel it, you will be able to see it. Block sanding, patience and a good eye are the only way to get it right.

When I am satisfied that the filler is as good as it can be, I will cover it with a coat of ‘filler primer’; thicker than the sandable black.

The focal point of any motorcycle is the fuel tank.  Our Puch is equipped with a nice, teardrop saddle type tank.  It’s actually two tanks; one on the right for gasoline, one on the left for 2-stroke oil.  You see, although the Puch was made in 1961/62, it incorporates a positive injection system that eliminates the need to premix oil and gasoline.  The Japanese would incorporate this feature in all their 2-stroke designs in the following years of the decade, but we see it here early in the Puch; another example of its advanced engineering and one of many reasons that this is a significant motorcycle.

Filing excess epoxy filler

The interior of the tank is fine – the oil side (on the image right, note the dip stick!) is naturally corrosion free and the fuel side looks like it was recoated in recent years.

In the last post we had wire-brushed the tank to remove corrosion and expose flaws.  We filled a seam  in the nose of the tank and a dent behind the oil filler neck with JB Weld metalized epoxy.

In this photo, we’re using a very coarse ‘body metal file’ to rip off the excess epoxy and shape the repairs.

Patches and tank rough sanded

In the series at left, we make the tank ready for it’s prime coat by working down from coarse sandpaper to fine 400 grit.  This course sand sets the contours and makes sure there is no rust anywhere in cracks and grooves.  The surfaces must be relatively smooth.

After wet sanding - front view

Here is the tank after wet-sanding with 400 grit wet-or-dry paper and a sanding block. It’s shiny because it is still wet.

After wet sanding, rear view

It’s very important to ensure that the transitions between layers of paint exposed by sanding are ‘feathered’. That is, the transition should be very gradual, showing swaths of colour from each layer around the outline of the area. This is so that when we apply new paint, there are no visible lines showing through from the surface underneath.

Underside, anti-rust and primer coats

Dried and degreased, the tank is now ready for its prime coats. This shot underneath shows two applications. The centre, saddle area has been painted with anti-corrosion paint, as we have done with all interior painted surfaces. The outer, underside surfaces show the first coat of sandable black primer. Remember, this area was a mass of grease, dirt, rust and chipped paint before we began this process. Now look at it!

First coat of black sandable primer

Finally, here is the topside in a fresh, very liberal coating of sandable black primer. As mentioned in previous posts, this stuff allows the colour coat to adhere properly to the surface but it also covers lots of irregularities, including the feather-sanded areas.

Next step is to block-sand the primer layer and respray it prior to the colour coat of black enamel.

The Rev

Today I really wanted to post a raving diatribe against the moronic design of motorcycle battery terminals, but that’s going to have to wait.  I think I’ll create a new category for Spirt of the Ride called ‘Stupid Motorcycle Tricks’.

On that subject, I wanted to show you a picture of something I have never done before.

There are several Motorcycle Encyclopediae in my library and in them you can see historical examples of unconventional motorcycle applications.   In war as machine gun carriers, as bakery vans with sidecars full of bread, as roadside assistance vehicles (think CAA on a bike), paramedic response and so forth, not to mention the venerable Harley Servicar trike or ‘pie wagon’  popular with parking enforcement and commercial delivery alike.

And why not?  Bikes have an inherent advantage where congestion interferes with commercial delivery .  Since Toronto has become one of the most congested cities in North America, the Rev has taking to leaving the Sprinter van at home and bundling everything onto the Bandit for a quick dash across town.

Motorcycles can be Commercial Vehicles

Aside from the limitations of weather, I have found that the motorcycle saves me a lot of time and money, not to mention giving access to underground parking and other tight urban places.  I can carry all my tools and detailing supplies without too much trouble.

But this week was the first time I tried to carry a ladder.

I’ve been working on the Menezes provincial election campaign in Oshawa and one of my tasks was to design, get printed and install the campaign office banner.   The banner had to install on a 146″ x 22″ light box over the door, about 12 feet up.  Fortunately, I have a very nice folding aluminum ladder that stores in a package about 5 ft. long.

Ladder on a motorcycle? Why not?

As you can see from the photo, I was able to lash the ladder to the back of the Bandit without compromising either my seating position, or the stability of the bike.  Installed flat, it offered no discernible aerodynamic drag and the light weight did not adversely affect handling.  I made it out to Oshawa in under an hour and had the banner up soon after.

Here is a photo of the Rev on the ladder, just to give you an idea of the height at which I was working.

Climbing the political ladder?

Of course, the Suzuki Bandit is a ‘standard’ – the traditional motorcycle pattern with handlebars and sit-up, feet-under-you riding position and a centre stand.  My Bandit has the factory rack with Givi plate on it.   You could pull this off with a similar ‘naked’ bike from another manufacturer, but likely not with a cruiser or sport bike.

the Rev

The path to a better-than-original finish includes several distinct steps.  As always, the more effort you put into the parts early in the process, the less messing around you will have to do during the final steps.  Since errors tend to accumulate a the process goes forward, one has to have high standards at the start.

1962 Puch Twin Single restoration - chainguard cap, primer coat

Here is an example of Puch sheet metal after it has been media blasted to remove corrosion, then covered with a couple coats of sandable black primer.  As well as providing a surface that will stick to bare metal, this stuff is almost like body filler.  You can use a sanding block and 400 grit wet-or-dry to even out and cover a lot of imperfections.

1962 Puch restoration, chain guard cap, colour coat

Here is the same piece after the first coat of black acrylic enamel.  Although enamel is harder to work with than laquer, it is more durable and more accurate for this bike, which was originally  painted with enamel.  After I am satisfied with the colour coat, I will cover it with an acrylic enamel clear coat.

1962 Puch restoration, headlight shell, prior to paint

You will remember that the headlight shell could not be media blasted because the red and green lenses are riveted to the shell.  I had to remove the corrosion using a power drill and a rotary wire brush, file down the pitting and hand sand the whole thing  Bare metal shows where the shell was once very rusty.  The flange, around the headlight opening, was particularly bad, as it would trap water.  Note that you must ‘feather’ the areas where paint has been removed or the line will show and spoil the result.

1962 Puch restoration, headlight shell, primer

… and here it is after primer.  I masked the lenses with some thin masking tape.  This is a critical piece because it is one of the first visual highlights viewed, right after the tank. I’ll show you the very stunning result tomorrow after I apply the colour coat.

1962 Puch restoration, tank, before starting

Ah, the tank.  Actually it was in pretty good condition.  Here it is prior to any work.  Note the dent in the left side, behind the oil tank cap.  The tank is going to need the same treatment as the headlight shell – wire brushing, hand sanding, as well as a bit of filler for that dent and a weld seam on the front.

1962 Puch restoration, tank, wire brushed, filled

Here is the tank after wire brushing.  The area around the tank cap necks got a lot of attention to remove the rust from the seams.  There is a fair amount of factory filler in this tank and it looks pretty ratty at this stage. However, once filled, sanded and primed, it will look terrific.  The area I’m pointing to is the dent from the previous photo.  I have filled it with JB Weld, which is a metallized epoxy, MUCH stronger than body filler.  Once it sits overnight, I can file it down to the original contour.

Some of the alloy we are polishing is attached to the engine – specifically the engine side covers, plus a few smaller parts.  Puch cast brake and shift levers out of alloy, so they get the treatment too.

Primary chain and clutch assembly

After draining the ancient gear oil from the gearbox, we can remove the alloy left side cover, a very nice oval shaped piece.  Here is a chance to look at another outmoded motorcycle practice, the ‘primary chain’.  That’s the roller chain that runs from the crankshaft sprocket on the left to the clutch assembly in the centre of the photo.

The purpose of the primary chain is to transmit power from the crankshaft to the clutch mechanism and gearbox. It’s a throwback to the earliest days of motorcycling when the engine and gearbox were separate units.  In the ’50′s, ‘unit construction’, which integrated both systems in a common engine case became popular.  The Puch is unit construction of course.  But as with other early unit designs, the engineers chose to retain the primary chain.  Modern bikes mostly rely on gears to do this job, but a few holdouts remain.  Harley big twins, for example, are real throwbacks; not only do they use a very long primary, but they separate engine and gearbox.  The Sportster has always been a unit construction, but like the Puch, with a primary chain.

Removing the carb

Here’s something else unusual about the Puch.  I have unclamped the carb and am  rotating it to slide it out of its manifold.  Note the location!  It’s stuck on the left side of the engine where it can feed the crankcase, not the back of the engine where piston-port two strokes typically mount it.  Keep in mind that Mr. Twingle is a two-stroke, and a very unusual one at that.

Rust through hole in bottom of left side pod

As we mentioned in part 1 of Sheet Metal, several parts are either so corroded that they have holes, or cracks around drill holes resulting from metal fatigue.  We are going to weld up these defects, either with filler rod or in the case of large holes, patches.

Thinned metal removed, patch tacked in place

This is very tricky business if you are using a stick welder as I am.  The sheet metal is not very thick to begin with and in the corroded areas, it’s  paper thin.

Grinding the repair area smooth.

The process of arc welding such thin steel is laborious, time consuming and dirty.  One has to slowly build up the rim of the hole with spots of weld rod, them gradually add filler until the hole is closed.

Remember what this area looked like from the previous post?  In this case, I decided to simply weld up the entire area, including the original bolt holes.  In this photo, you can see the preliminary results of first welding, then grinding the area smooth.  While doing the repair, I try to hammer the steel back to its original shape.  Once this area is reasonably smooth, I will finish it with a thin coat of JB Weld epoxy as body filler.  Then I will re-drill the bolt holes.  Finally, I will prime paint and sand this fender just like the other parts.

Surface Prep

Work on the parts starts with a wipedown with surface prep. A paper towel shows the oils and dirt removed. Not a big deal, the primer is quite tolerant, but with painting, compromises pile up.

Sandable Primer

As expected, the wonderful sandable black primer leaps on and clings tenaciously. It’s a fast dry. Black primer under a black top coat makes for better coverage later.

Inside anti-rust paint

We don’t forget the insides either. The unseen inner surfaces most affected by corrosion are treated to a couple of coats of oil-based anti-corrosion paint. I’ve chosen semigloss.

Primed, ready for sanding

Here are the parts with a couple coats of the primer, prior to sanding. The primer acts like body filler to even surfaces and give a smoother, more custom appearance.

Now the fun part.

Old wheel is a reference

We start by putting all the wheel parts loosely together – polished hub, rim, spokes and nipples.  It helps if you have a reference handy, such as the other wheel which you thoughtfully did not destroy just yet.  Note that Puch thoughtfully made the front and rear wheels identical.  The only difference is the chrome hub cap on the front wheel vs. the exposed sprocket mount on the rear.  You could easily swap them and their brake shoe carriers.

Spoke hole locations differ

You will notice the little things that make a wheelwright’s job a little easier.  Note the difference between the location of the spoke holes.  The spokes with heads closest to the edge of the flange pass over the next one in series.  This is what you call a ’1-cross’ wheel.

Dimples point in spoke direction

Here you can see that the holes in the rim for the spoke nipples are dimpled in the direction the spoke is angled.  You have to make sure to line up the right combination of dimples with the holes in the hub flange.  Oddly, in this case, the manufacturer of the new replacement rim made a mistake – the dimples are 180 degrees out of phase vs. the original rims.  On the OEM’s the spokes on opposite sides of the rim should point in the same direction, but the dimples here force us to reverse that pattern – corresponding ‘outer’ spokes must point in opposite directions.  No harm done, but it’s the kind of subtle issue one needs to watch for.

Last spoke and nipple on left side

Following the pattern of the old wheel, we carefully lace the hub into one side of the new rim with the new spokes and nipples.  Usually it’s a good idea to install the spokes loosely – screw the nipples on just enough so they catch.  We’ll tighten them later during wheel truing.  Then we flip the wheel over and do the either side.

Pretty 'new' wheel

Voila.  The finished wheel looks great.  Next step for this unit is a trip to the truing stand where we adjust radial and axial symmetry by tightening the spoke nipples in a specific pattern and then measuring the runout.

RevDrG

Remanufactured motorcycle tires?  Z-rated?? For $150 a set (120/180)???

True!

They’re called ‘Tomahawk’ and they are made by the Dresser tire company - http://www.motorubber.com/ who transform worn-out motorcycle tires into new by a process called ‘revulcanization’, moulding new rubber onto the stripped and x-ray’ed doner tire body.   If you are at all interested in saving big bucks and being green about it, go to the website and read about the technology- it’s been used by  the aircraft and trucking industries to save money on expensive tires for decades.  Dresser uses the same process and equipment to produce these bike tires as FAA certified aircraft tires rated to 200+ mph.

Bandit wheel wearing sexy stuff

If we were lucky enough to live in the 48 states, Dresser would also throw in the shipping!  As it was, shipping to Canada included, I saved about $100 bringing them up.  That’s 25-30% less than new here. Not shabby, but the tires are going to have to be 1st class.

Here is the T3 rear mounted on the Bandit’s wheel.  The fresh tire mounted and balanced without incident. They are heavy, like the reviews say, the rubber is generously deep which should extend their useful life. The bodies for this set are Dunlop sporting and the f/r patterns are reminiscent of Diablo’s.  (I hope they wear longer than the Pirellis).  The profile is very smooth vs. the peaky styles currently in vogue – something about the texture and density of the revulcanized rubber compound feels like reassuring quality.  Tire moulding is very clean and as you can see from the pic, they look nice on the bike.

Tomahawk looks like Diablo

Riding the tires was a happy surprise.  Comfortable and broad, they absorbed road irregularities and ignored the streetcar tracks in my neighbourhood. The profile encouraged a progressive, neutral role and the grip turned the bandit into a sport bike.  Gently apply push-steer pressure, induce a light role into the curve and relax.  Sticks like glue.  I scuffed ‘em in on a 500+km long weekend trip and they showed no appreciable wear.  No chance yet for a wet test, but that too is inevitable.

By the way, that oh-so sexy sprocket is the Supersprox – a hardened steel sprocket, riveted to a light alloy disk – voila!  Hard, durable sprocket surfaces for long life, coupled with reduced rotational mass.  Like the wave rotor behind it, the Supersprox helps make up for the added rubber.

The Rev