Righto, time to attack those last few bits and bobs that seem to defy the normal passage of time.
I don't know about you but a few signature items leap to front of mind when someone says "851" to me: the white frame, the "fuller figured" fairing, the front intakes like a couple of letterbox slots.....and if modern huggers are a barely there G-string over the back wheel, the 851's hugger is a big ol' pair of granny knickers. Not that it bothers me, it's just indicative of the "gift-wrapped in ABS" trend at the time, think BMW K1, CBR600/1000F, Bimota YB8 etc.
The OEM plastic hugger had seen better days so I'd replaced it with a carbon unit, in one of those frustrating shipping deals where you are paying for air to be transported rather than any actual weight. But it's nice quality and fit perfectly....except for a couple of things that could never have been anticipated when it was manufactured:
1. Modern tyres like a 200/60 Pirelli fitted to a 6" rim (OEM was 5.5") having a much taller profile
2. Someone trying to fit a road part to a race bike
By that last point I mean that back in the day if you were serious about racing one of these things you either purchased a full on customer spec Corsa machine or bought a pallet load of Corsa parts to convert an SP. A known issue with the 851/888, something corrected somewhat with the ground breaking 916, was not quite enough weight over the front wheel. Remember that front mount ECU? Another fix would have been found buried in that pallet of parts: a 20mm longer Corsa swingarm with different brackets for the corresponding Corsa-specific hugger.
Corsa vs road swingarms, although the end caps on the road arm make it seem longer than it is:
But 30 years on the Corsa-lite solution for those of us who don't have a bank account with a Monaco BSB, is to just push the axle back as far as it will go, some even modify the axle slots to gain a few extra mm. No good deed goes unpunished and you pay for this shortcut with the trailing edge of the hugger almost rubbing the rear tyre. No way is a tyre warmer fitting under there and at speed, with a bit of tyre growth, it was going to have a very limited lifespan. The twin pipes make it difficult but you can just see here that with the axle pushed back the rear edge of the hugger is on the endangered species list:
There was a lot of squinted eyes, looking from different angles, head on the side, and my tongue was drying out from trying to hold it just right....but I eventually came up with a Jenny Craig version echoing the lines of the original:
And I'm happy enough with the result:
Next up was the trickier job of integrating some sort of belly pan to catch stray fluids trying to make a break for freedom. Belly pans are a fairly recent mandate from the powers that be, back in the day you just put up with whatever fluids fell or vented onto the track.
WARNING! WARNING! TANGENT ALERT!
The following is kinda-sorta-nearly related to the crap on track thing, I find it interesting...but feel free to scroll on by.
4 cylinder engines, even at just 750cc vs 1000cc twins in WSBK, have one advantage over the L-twin Ducati's: pumping losses.
Compare the inline 4 below (think 851/888 contemporaries like ZXR750, OW01 etc):
And V4 (RC30, RC45):
If you can get your eyes to go in two different directions at once you'll notice the action of each piston rising and falling is cancelled by the opposite action of another, right?
Contrast this with Ducati's L-twin:
The rods share a single crank journal, only separated by the 90deg cylinder offset, so for large periods of the 360deg crank rotation the pistons are actually rising and falling together. The fact there is 270deg between firings is what gives the twins such great inherent traction, but this arrangement also leads to large variations in crankcase pressure: when both pistons are rising a relative vacuum is pulled, dragging on the pistons...when both are falling pressure is created, acting against the pistons. This pumping action costs horsepower, not a lot, but we're racing for a World Championship here. Little wonder Fabio Taglioni's most famous design was nicknamed "pompone" or "big pump".
Back in the day the cure was as crude as it was effective, have a dirty great hole in the top of the crankcase vented directly to atmosphere via a reed valve and hose dangling somewhere out of the way of the rear wheel. Oil mist? To quote a Ferrari line: "whatta issa behind does notta matter!" (in your best/worst Italian accent).
Check out Roche's 1990 Factory racer and note the vent hose exiting up under the rear cam belt pulley and on past the shock preload adjuster to atmosphere:
John Britten's VR1000 masterpiece had pretty much the same thing, albeit with a little oil/air separation (standby for gratuitous Britten goodness):
....and much more style:
On that Roche bike above the undertail is just a plain carbon panel cable tied in place, with the ECU still in-situ. But it is right about now the formula originates for many iterations of Ducati race bikes to come: from this point on the ECU was moved up the front, and an oil/air separator "breather box" was incorporated into that undertail panel:
The breather box basically adds to crank case volume so the bigger it is, and later models like this 888 unit were huge, the less the pumping effect of the pistons affects crank case pressure. This now vents "clean" air into the airbox rather than straight out the back...but there is still no thought given to containing fluid leakage in the Britten above with it's beautifully exposed engine, or Falappa's Factory 851 below with it's nether regions on display:
And to this day that's how how virtually all 851/888 race rep fairings are manufactured, with a seam underneath where the side panels join towards the front and just completely open for the remaining portion where the exhaust hangs out.
This is obviously "unasseptable" (in Super Nanny-speak) these days. There are some belly pans around for Monsters and 900SS', which have a bulbous exhaust protrusion underneath, but you still have to marry it up to the 851 panels which I'd seen done with varying degrees of aesthetic success.
But the change commenced on earlier bikes fully arrived with the '96 955 giving rise to an enclosed belly pan. Here's Troy Corser in '95 on his 916 Factory bike:
Versus his '96 championship winning 955:
"Yeah yeah, get to the bloody point will ya?!" Orright, just explaining how I arrived at using an evolution of the above belly pan: a slightly tatty carbon 996RS unit, again shipped with a big lump of expensive European air. It had partially delaminated in one area and was a tad scratched up it so was cheap enough at just 60GBP, unfortunately shipping was virtually the same...sigh.
But this is what arrived:
It's not immediately obvious when you see it in isolation but that curved wheel recess is for the rear wheel and the narrow section goes to the front:
But look how looooong the thing is, and that bulge to clear the exhaust is awkward.
So a good long time was spent rolling around on the concrete offering it up to the fitted fairings, then to the naked bike figuring how best to integrate it, propping it up in place then stepping back etc. It looked like it might integrate into the 851 panels quite well if fitted in reverse....but in the end there were too many little wrinkles and lines that didn't gel with anything....aaaah who am I kidding, I just didn't have the stones to risk cutting up the side panels and then not be happy with the result, alright? So I played it safe and worked away at fitting it inside the fairings.
The first step was to carefully heat the awkward exhaust bulge to near melting point and clamp it between a couple of pieces of timber, once cool it was near enough to a uniform shape. Next up was a cut and shut job, slicing off the curved recess end panel, cutting out an approx 75mm section, then re-epoxying the end panel back in place. A read of the rule book told me it only has to hold 3.5litres of fluid, which gave me plenty of scope to trim it to fit.
Bewdy, I've got a belly pan that fits inside the fairings...but how do you mount the bloody thing? I'm looking around and there is almost nothing to hang it off, particularly at the front, but I finally came up with this:
I couldn't see any other option than make some brackets and use the lower fairing mounts:
Supporting the front was even worse, there are no attachment points even remotely close. There's probably something better staring me in the face but this was the best/only option I could see:
The front bracket is hanging off the foremost exhaust manifold stud:
So yeah, just one of those jobs where 75% of the time is taken up figuring out what to do, with only 25% the actual doing.
