American by Name, Italian by Soul

If I asked you to guess the 70's four-cylinder bike I'm thinking of with 750 in its name, I can guarantee you'd say Honda CB750.

And you'd be wrong.

I'm thinking of something much more exotic.  In fact, I'm thinking of something that cost almost twice as much when new than a CB750.  It was an aristocrat's four-cylinder superbike, one dripping with racetrack engineering, pedigree and hardware.

I'm thinking of the MV Agusta 750S America.

The 750S America was an evolution of the stunning 750S, Count Agusta's race bike for the street.  Except that it wasn't a race bike.  Agusta was terrified of privateers buying the 750S, entering races and then losing, thus tarnishing the mighty MV Agusta name.  To prevent this from happening, Agusta ordered the 787cc four to be neutered.

The cylinder head was filled with tiny valves, the engine was fed by tiny carbs, and the final drive was done via a shaft.  Cheap rear shocks and a poor front drum brake were also added.  What resulted was an overly expensive bike that would get beaten by the much-cheaper CB750 and absolutely slaughtered by the Kawasaki Z1.

To remedy this, MV went back to the shed and set out to give the 750S the performance it demanded.

First, the heavy front drum was replaced by twin discs.  Next the engine was given a refresh.  The tiny Dell'orto UB24 carbs were replaced by larger Dell'orto VHBs.  Finally, the valves grew and so did the compression.  What resulted was a bump in power from 66 hp to 75 hp and a 9,000 rpm redline.  These changes allowed the 750 to finally reach its advertised 130 mph top speed.  The shaft final drive and heavy weight remained but the bike had an overall more visceral feel to it.

Performance wasn't the only thing that was updated.  To accentuate the new found power, MV gave the bike's styling a refresh.  The rounded tank was replaced by a longer unit with more squared-off styling and large cutouts for the rider's knees.  The classic bum-stop seat of the 750S was replaced with a square stop seat covered in brown suede.  Nothing says 1970's chic like brown suede. 

Over the next few years, the 750S America was treated to a number of changes.  The spoked wheels were replaced by cast wheels and the silencers were redesigned.  The four was eventually bored out to 837cc, which meant more power and more speed.

The MV 750 really came into its own at the hands of tuner Arturo Magni.  Magni replaced the suspension with top-quality units and put the bike on a massive diet.  The shaft drive was also tossed in favor of a chain.  Magni's hands also found their way into the engine, which saw displacement rise to 861cc and power rise to 92 hp.

The plummeting weight and increasing power meant the 750 was getting closer to the street-legal race bike it should have been.  Through continued evolution at the hands of the factory and tuning shops, the 750 was displacing 1,066cc and belting out 118 hp by the end of production in 1980.

So, then, it's hard to sum up the 750 and what makes it so special.  It definitely was a uniquely Italian answer to the superbike question.  At first glance, it seems to be a beautiful piece of Italian sculpture bolted to an industrial lump of sand cast aluminum.  On paper, it was heavy, expensive and complex.  In reality, it was heavy, expensive and complex.  It was also a bit slow at first but that was quickly remedied.

So what is it?  What is the MV 750?

I can tell you in one word: timeless.

The MV 750 is timeless in that it was totally exotic, totally different from every other motorcycle out there.  It was very expensive and sold in minuscule numbers, quite in contrast to the cheap and hugely popular fours from Japan.  And while the fours from Japan were raced, destroyed, ruined, chopped and thrown away, the MVs were kept and appreciated.  These days, the fours that could run over the MV 750 are practically given away while the MV silently increases in value. 

To sum it up, the MV 750 is as all great art is: a curious oddity when new and then a cherished piece when its time has passed.

Ducati Updates - Part Deux

Since I picked up my Ducati's cylinder head this weekend, I thought I'd share some pics of it with my non-existent readers.

Right; let's start the show:

As you can see, the head was cleaned and sandblasted.  New guides, valves and seats were also fitted to the head.  The spark plug hole was cleaned and Heli-coiled because only half of the old threads remained.

Here's the new guide on the exhaust side...

...And here is the new guide on the intake side.

Here you can see the other ends of the new guides and the new valve seats.  They look fantastic.

Here's the newly-repaired spark plug hole.

Here are the new valves.  The one on the left is the intake and it's 36mm while the one on the right is the exhaust and it's 33mm.

Here are the old valves and the old guides.  The rockers were hitting the old valves on an angle, wiping out the guides. 

The old valves were quite a bit longer than the new valves, as evidenced here:

And here:

The height differences were remedied with lash caps, which are little hardened caps that fit over the tops of the valves, making up the differences in height.

I think the head turned out wonderfully.  I'm happy with the work and I'd like to give a big thank you to Dave at Dutchman Racing who did the work.

Ducati Updates

In the past few months, work on my old rusty Ducati has been few and far between.  It's not that I've lost interest in it, I've just been riding my bikes that actually work. 

But all has not been lost in that time.  I've decided to make the bike look like a proper 1965 Ducati 350 should look.  I have the complete bodywork for a 1966, with its squared-off tank, fenders and headlamp but it just wasn't right.  The '65 350 Sebring shared its bodywork with the 160 Monza Junior and that was the only year the Sebring had the rounded tank.  Being that it was a one-year-only deal, I think it would only be right to make it look correct.  Besides, the 1966 bodywork is really ugly and the proper 1965 bodywork is much better-looking.

So that meant finding this bodywork.  Scouring Ebay for weeks turned up nothing.  Scouring other parts of the Internet also turned up nothing.  Clearly, this was not going to be easy.

But then, by chance, the right tank popped up on Ebay.  After an intense bidding war that resulted in me overpaying by quite a lot, the tank I needed was mine.  It's not an actual Sebring tank but an older Monza Junior tank that has black painted over chrome.  The chrome stripes were not only incorrectly lined up (famous Italian build quality) but were quite rusty.  Thankfully, the rust was only on the surface and was gone after an hour or so of rubbing with aluminum foil and steel wool. 

The rest of the tank is in good shape, too.  The inside is very clean and there only minor imperfections on the outside.  The gas cap is also in good condition, thereby saving me money. 

I think it was a good purchase but it leaves with a decision to make.  See, I like the chrome, even if it's dull and slightly pitted.  Since the bike will never be a concourse restoration, I'd like to leave the tank as it sits, making the bike look like a survivor instead of a 100-point resto.  But the other half of me wants to paint it and make it look new.  Fortunately, I have a million other decisions to make regarding the bike so paint choice isn't pressing at the moment.

Also new in the past few months is a bunch of stuff for the cylinder head.  After I took it apart, I got a good look at the valve seats and they were knackered, to borrow a phrase.  It seems years of sitting while being exposed to the elements caused the seats to corrode.  Who knew?

Anyway, I don't have the knowledge nor equipment to deal with installing new valve seats, so the head went off to a machine shop.  From the machine shop, more bad news rolled in.  It seems the valves were cracked and the guides were severely worn.  The rocker arms were hitting the valves off-center and causing the valves to open on an angle, wiping out the guides.  Lovely.  I ordered new valves, guides and seats and they, too, went to the machine shop. 

After a few weeks of work, I should be picking the head up this weekend.  With the cylinder head sorted, I can finish boring the cylinder liner to fit the new 76.6mm piston and then bolt the engine back together.  All I need now for the powertrain are steel and fiber plates for the clutch, a point and condenser and a spark plug.  Once the engine is finished, I can move on to the wheels, tires, brakes, suspension and bodywork.

In all, my rusty Ducati is coming along and my goal of it being roadworthy before the December 21, 2012 apocalypse is within sight.