Automotive & Things That Move

We’ve now owned the ST4 for about two years. We bought the bike “new” from the dealer with 7000 miles on the odometer. As a demo bike, the vehicle had never been titled. We now have over 13000 trouble free miles on the machine.

First impressions of the ST4 as a driver upgrading from the Monster 750 are power and comfort. My wife certainly enjoys the significant increase in seating area and leg room. The Monster passenger seating position pushes the passenger’s legs up very high and the seat area is little more than about 10X7 inches. The seat area on the ST series is at least double with much lower foot pegs.

The ST4 features a very similar engine to the 916 Superbike, but not the same. By specs, it seems aimed at the target market producing a little more lower end torque. By feel, it’s still a blast. Power rolls out in gobs at about 4.5 to 5k rpm and keeps getting better all the way up to 10k. As with most Ducati motors, you get about 80% or greater peak torque throughout most of useable rev-range. This is the differentiator for a big twins and closed cam (Desmodromic in Ducati speak) valve trains. For those not familiar with the valve train, Ducats are known for not having valve springs. Traditionally engines are equipped with one cam and lifter per valve with a spring that closes the valve and maintains lifter contact with the cam. Valve timing greatly impacts the power and torque performance of an engine. Traditional spring lifter systems are limited in their range by the capability of the spring to push the lifter and valve back up fast enough to maintain contact between the lifter and the cam. Should the cam spin too fast, the lifter will float off the cam like passengers on a roller coaster going over a peak. When this happens, the lifter slaps back down onto the cam surface and causes surface damage that deteriorates engine life. A closed cam system like the Desmodromic valves of a Ducati on the other hand has a lifter and closer instead of a spring. This nearly eliminates the problem of valve float and provides the engine designer with the ability to create some fairly extreme cam profiles resulting in gobs and gobs of torque throughout the rev range.

So back to the bike. I like most everything about this machine. It’s fast, it’s agile, and most fun is that it is a sleeper with the hard bags attached. Many kids think you’re on a gold wing or something at the stoplight. They don’t seem to expect the wheelie and big twin bark that leaves them scratching their heads.

Things I don’t like are all maintenance related. Servicing a Ducati is expensive. It’s cheaper to drive my Dodge pickup getting 20MPG in terms of regular maintenance and gas. Fuel economy is fine on the ST4 coming in around 40MPG most of time. But, tack on the ~$800-$1,000 service every 6000 miles for valve shimming and tires and you’ve nearly doubled the cost per mile of the Dodge. Living in New England means wintering the bike. Wintering means battery maintenance, which is not considered in the design of the bike. Granted, Ducatis are race bread. Meaning, there is little on the bike that isn’t A: to make it go faster, or B: to make it turn or stop better. But who hasn’t accidentally turned the key one stop too far and left the lights on for the afternoon? The other is charging in the winter months. The entire fairing system has to be removed including the dash surround and the mirrors to access the battery, even just the terminals. After performing this operation two time, I made some modifications. I corrected a wire undersize issue that affects warm start (and weak battery) condition by upsizing the wire from the battery to the starter and ground. Also, I added a short lead, with a rubber cap on the end, to the positive post of the battery that can be pulled out of the cooling duct when I’m having a stupid moment and need to jump start or recharge the battery.

I give this bike a B+. A great blast to ride, but the cost of ownership makes me think twice about riding it, which is sad. Unfortunately, Ducati will not likely make this valve train less maintenance heavy as it drives their service revenue.