OB's motorcycle travels, projects, ideas

OK, so being an undeniable, and hopelessly inveterate tinkerer by nature, I am absolutely unable to resist modifying any motorcycle I ever purchase.

I tried, I REALLY tried, to avoid modifying my beautiful, red Italian Ducati 996 motorcycle, but have been totally unable to resist the temptation. The problem is that I vacillate between building a more competent racetrack worthy Ducati vs. a better street motorcycle. The two seldom have much in common.

On the one hand, a track bike is built to be fast (and requires revving the motor hard and high to extract that power), light (remove all the street gear such as horns, lights, mirrors, indicators, etc), stiffly suspended (no comfortable, soft suspension here!),  and by it’s nature, temperamental and less reliable.

While, a good street bike must be comfortable, have all the street legal gear, have compliant suspension, a nice, wide powerband that does not require revving the guts out of the motor, and be relatively quiet and economical. Two almost polar opposites.

So, what to do?

I could leave her entirely as she is!

Nahhh, we know THAT’S not going to work, for me.

So, after some deliberation with the help of a couple (OK, maybe a few) glasses of vino rosso, and acknowledging the fact that despite my beautiful old Ducati being a very good sport bike (in its day, back in 1999), any modern Japanese or Italian bike is going to run away from her on the track, and it’s a little pointless to spend huge amounts of money to simply get her reasonably close to competitive on the track, and also because I am personally now approaching 50 years of age and have finally started to believe in my own mortality, I have decided to build her into a very lightweight, no frills, but comfortable, STREET bike.

My overriding theme for this project will be:

• Low cost! (I have to fit into a budget that is framed by whatever I can steal from Karen’s grocery budget, and without detection)
• Light weight. I intend to cut off, remove, replace, drill and generally lighten the mass of any and all components, to make the bike as absolutely LIGHT as possible. My stated goal for the bike is 340 lbs wet weight, ready to ride with 1G of gas in the tank, fully street legal. Impossible? Maybe….but worth a try. This will be a reduction of around 110 lbs from the stock bike.
• Wide, torque-laden powerband from the motor. The aim is to make a motor that pulls hard from low and lid RPM levels, while still having a nice boost on top. Goal is 140HP with strong, flat torque. Displacement, higher compression, more efficient exhaust and airbox design and careful cam and fuel injection and spark timing tuning to come! I already have a farly hot 998 Testastretta motor waiting to be fitted, with extensively and carefully ported heads, big intake valves (42MM), hot 998R cams. I am adding a set of Ferracci 13.5:1 lightweight pistons and will have the crank balanced, and with a Nichols lightweight flywheel providing a touch more throttle response. I will use conservative cam timing for strong mid-range torque, and exhaust and intake tuning done on the dyno, before final fuel and spark mapping is completed for the ECU.
• Comfortable! The bike will have higher handlebars and a nice, wide, comfortable seat, and relaxed footpeg ergonomics to prevent my large body from having to contort into some crazy Italian monkey position. As a tall man, I am less concerned with seat height, so can afford a high seat to allow less bend to the knees. Clip-on handlebars will be located above the triple trees, and not below them, for additional comfort. More on this later, as the clipons are dependant on whether I retain the telescopic forks design, or build a new Hossack style front suspension – which would be VERY cool.
• Styling. I’m thinking the bike will be conventional naked design, with minimal plastics. No fairing sides, basic seat, open engine design, minimal instrumentation. Simple, round taillight and indicators. The only real “plastics” besides the airbox “gas tank” cover, will be a carbon fiber belly-pan to cover the low-mounted lightweight battery, coolant overflow, fuel pump, regulator/rectifier and some electronics.
  I intend to run open cam belts with painted red cam pulleys on each of the quad overhead cams and the drive gear, and an open dry clutch cover with red pressure plate, as the only real “styling” concession (and as this reduces weight, it fits the overall concept!)Think LIGHT WEIGHT…and what is absolutely necessary only. No frills, nothing glitzy, shiny. No unpainted carbon or doodads…this is NOT meant to be a Starbucks / garage queen style bike!
• General Design.
  • Basic concept here, is simple, single, round conventional Halogen headlamp,
  • round, analog stock rev counter centrally located, small bicycle digital speedometer,
  • small, lightweight aluminum bar-end mirrors,
  • underseat or under ”tank” fuel tank, with a painted carbon fiber“gas tank” cover over the oversized custom carbon fiber airbox,
  • twin thin-wall custom exhausts, conventionally located on each side with upswept ultra-light stainless steel Burns mufflers,
  • Buell lightweight front wheel and ZTL single brake system,
  • Hossack front suspension with titanium fork girder and links, connected to a single Ducati rear shock, revalved and sprung for the front, with 6” of travel.
  • Lightweight, dual-sided custom titanium swingarm, direct linkless connection to side-offset Ohlins rear shock for access and header clearance, valved and sprung for 6” rear travel.
  • Drilled, stock Ducati 999 rear brake and wheel.
  • Lightweight custom titanium trellis frame, to tie the Ducati motor as a stressed member, to the rear shock mount and Hossack front links and front shock mounts. Simple support brackets for custome carbon seat, custom aluminum gas tank, custom carbon airbox, lights, etc.
  • Huge, 15L carbon airbox (tunable for volume by interior sealed foam carbon coated blocks) for added Helmheitz resonance tuning.
  • 996 Wiring harness and Ducati Magneti-Marelli 1.6M ECU with custom EEPROM chip for tuned fuel and spark and environment trim maps.
• All the frame and suspension work will be built in-house by myself, to cut costs, and as the major work of this long-term project.

Pics and build story to follow.

Note: this is a LONG TERM project. I expect it will take me two years to complete. I’m in no rush, and enjoy the work itself.

Thoughts, comments and suggestions are always welcome…but will be moderated to exclude the silly, or off-topic commentary!

EDIT May 31, 2009:

OK, have decided to take a more realistic approach to the project (primarily because I’m MISSING not riding the old Duc so much!)

Phase 1 – is to use the standard main frame, with mods to the cross-over tubes between the main frame spars, to fit the bottom half of the 999 airbox, and to use the stock swingarm and forks. This will CONSIDERABLY shorten the project, and hopefully allow me to finish before the end of this riding season, and allow me to work on the new frame over the next winter (when I MUST have insultated and heated the garage to avoid the freezing temps).

So, I have temporarilyn refitted the 999 motor into the 996 frame, and am cutting the frame cross-tubes to fit the 999 airbox bottom, which will be merged to the top half of the old 996 airbox, for extra volume.

I measured the original 996 airbox – it is a paltry 7L (excluding the airbox runners), plus the twin air runners which I measured at 1 L each (to the air filters), for a total of 9L for both cylinders.

The stock 999 airbox, on the other hand, measures a much larger volume of 10.4L without runners, so approx 12.4L including runners.

Now, I’m considering trying to separate the two cylinders intakes (and exhausts) to effectively make two single cylinders, from a tuning perspective, which I theorize will prevent the cross-cylihnder interference (from a wave-pulse tuning perspective) of the uneven firing sequence of the Ducati 90 degree V-twin crank. The advantage of separating each cylinder in the intake and exhaust, is that the flow characteristics and sonic wave pulse (Helmholtz effect) can be theoretically identical, vs. the stock motor where the cylinders flow and tune differently due to the irrefular frequency of the firing order of the motor, and the resultant fuel injection variances or differences needed between the vertical and horizontal cylinders.

It’s my theory, anyway, so why not give it a try? The disadvantage, is that I need an extra large volume airbox, because each cylinder will “get” only half the volume of the entire airbox, so eahc airbox half needs to be at LEAST the size of the original box (preferably bigger), and the air tube runners must be about double the size, if I’m having each tube feed a separate airbox half for each cylinder instead of allowing each cylinder to share both runners as they do in stock form.

So, big challenhes to find the space…but this is partically why I’m moving the coolant radiator to under the seat, together with the coolant expansion tank, so that I can build a custom fuel tank around the motor near where the stock radiator was. This will lower the COG as well, and move the fuel closer to the horizontal rotational axis of the overall bike and rider (doe better mass centralization and reduced polar moment of interia, which is such a big design factor these days.)

The stock 996/999 Ducatis have a very POOR mass centralization design, with very heavy exhausts and stuff out at the back of the bike, high up under the seat – about the WORST place for an exhaust. I intend to make space for the radiator (which is relatively light weight) under the seat, by building a twin exhaust myffler system in the conventional placement, along eahc side of the bike, angling up from near the rider’s foot pegs to the upper rear of the bike, as in the classic style. This will fit my “new” styling concept much better too, as it is somewhat “retro” in flavour.

I have already turfed the whole fairing, the HEAVY headlight unit and fairing brackets, the stock instruments and everything else I don;t need to get from point A to point B. The bike will have only a tacho and a small digital speedo, and perhaps an oil pressure light, and a single, simple 6″ round headlamp in the conventional location.

For cheap and simple comfort ergos, I have inverted the top triple clamp (it works both ways!) and removed the steering damper (who needs it anyway…weight savings again!) which has allowed me to raise the clip-on bars nearly 2″ on the tubes, for a much more comfortable position. I have retained the simple adjustable peg mounts, and lowered the pegs and moved them rearwards a little, to suit my long legs, for a more relaxed riding position.

Next on the agends….

Build the carbon airbox for the 999 lower half and some of the 996 upper airbox (as a mold), and build the rear seat subframe with brackets to hold the radiator and coolant expansion tank, and then work out the fuel tank location and start that construction.

Decide eexactly where to locate the battery, fuses, coils, and the electronic variable-speed water pump and regulator/rectifier unit, and think about using the bottom half of the stock fairing as a mold for the belly pan I intend to make, to hide some of the electronics and perhaps battery. MUCH to do!!!!