ST4 vs. ST4s

[Stopwatch]

I'm considering adding an ST to the stable, an '01 ST4 which is the last year of the 916 mill. The one I'm looking at is about an hour away and has been maintained by my local dealer who I like and trust. I'm curious to hear from people who have ridden both the 916 version as well as the 996 version what, if any, the real-world difference are between the two engines. The bike I'm looking at is blue, close to stock (DD headlight and a couple of other small upgrades), one owner, just had the full 12k service and is very clean.

I'd consider waiting for an ST4s but as I like to tinker with my motos (example one is my far-from-stock 900ss/sp) I figure I'd probably want to upgrade things anyway. The buy-in price difference between an ST4 and an ST4s in similar condition (and probably not in blue which is the color I really want) would be spent on upgrades like wheels and suspension, netting me a bike very similar in spec to an ST4s in every way except the powerplant. Plus, with this particular bike I wouldn't need to pop for a major service for some time.

Also, two more questions: did Ducati use the same suspect rockers in the ST motors as in the SBK motors? And: was the ST4s ever offered in blue?

[JohnBoy]

The ST4s never came in blue.

[dinskeep]

From what I can tell flaking rockers have appeared on all the non-testa desmoquattros. I did a fair amount of research on this, trying to decide if I wanted to go ST2 or ST4/s. I ended up deciding I'd just deal with the rocker issue if it appeared, and got an ST4s.

There was a thread not too long ago on whether the S suspension is worth it. It was for me, I went with the S for the Ohlins, not the greater power. Hell, the remote preload alone is worth it to me.

[Mike]

Originally Posted by PSsssp

I'm considering adding an ST to the stable, an '01 ST4 which is the last year of the 916 mill. The one I'm looking at is about an hour away and has been maintained by my local dealer who I like and trust. I'm curious to hear from people who have ridden both the 916 version as well as the 996 version what, if any, the real-world difference are between the two engines. The bike I'm looking at is blue, close to stock (DD headlight and a couple of other small upgrades), one owner, just had the full 12k service and is very clean.

I'd consider waiting for an ST4s but as I like to tinker with my motos (example one is my far-from-stock 900ss/sp) I figure I'd probably want to upgrade things anyway. The buy-in price difference between an ST4 and an ST4s in similar condition (and probably not in blue which is the color I really want) would be spent on upgrades like wheels and suspension, netting me a bike very similar in spec to an ST4s in every way except the powerplant. Plus, with this particular bike I wouldn't need to pop for a major service for some time.

Also, two more questions: did Ducati use the same suspect rockers in the ST motors as in the SBK motors? And: was the ST4s ever offered in blue?

I've ridden four ST4s's and one ST4 which was expertly tuned with the cam timing dialed in, performance exhaust and chip. I've never ridden a stock ST4 so I can't make a direct comparison. I can compare the ST4 with cams dialed/pipes/chip to a ST4s with pipes/chip. The ST4s has more power throughout the rev range, especially in the lower-mid rpm ranges but the difference on top was not quite as much as I expected. It's there but for street riding the main difference is the extra torque of the 4s. Even so, the regular ST4 is not anemic in the torque department. The 4s has a newer generation ECU which is not as easy to remap due to encryption but I think it offers a little finer granularity in terms of the injection mapping which probably explains the slight improvement in throttle response and maybe even fuel economy of the 4s.

Handling wise the 4s just feels more nimble and compliant, probably due mostly to the lighter wheels and Ohlins shock but I wouldn't discount the contribution of the aluminum swingarm.

The 4 valve ST's use the same rockers as the SBK motor but the cam profiles are different which may reduce the failure rate. Personally, I think the rocker problem is not such a big deal. I've had three fail in 30,000 miles with plenty of high rpm thrashing and I've replaced them with megacycle rockers. If I was on a budget I would just replace them with OEM rockers which are now quite inexpensive. I think the problem is not so much that the rockers are poor quality but that the surface of the cams are not very smooth. They are surface hardened with a treatment called "Parkerizing" and this leaves the surface a little lumpy. I've never inquired if there is a safe way to smooth the cam surface because it's so easy to replace a rocker if it fails.

The St4s was never offered in the slower blue color ;-) From memory, the ST4s was offered in Red, Yellow, gloss grey and, my favorite (the original 2002 release color), matte grey which is not a flat finish like the dark monsters and SBK's, it has a satin sheen that I think looks fabulous and rather stealthy at the same time.

Either bike can be turned into a wolf in sheeps clothing but the extra displacement of the 4s is hard to argue with.

[Desmo_Demon]

Originally Posted by Mike

Personally, I think the rocker problem is not such a big deal. I've had three fail in 30,000 miles with plenty of high rpm thrashing and I've replaced them with megacycle rockers.

I decided before even buying my (then new) 2002 748 that I'd just deal with the rocker issue when I came across it. At 5600 miles, I replaced four opening rockers because I wasn't too sure if they'd survive until the 12k service. I also swapped out 13-out-of-16 shims, so that may make a difference. I just view it as the nature of the beast (engine).

[Turbo]

Originally Posted by Desmo_Demon

I decided before even buying my (then new) 2002 748 that I'd just deal with the rocker issue when I came across it. At 5600 miles, I replaced four opening rockers because I wasn't too sure if they'd survive until the 12k service. I also swapped out 13-out-of-16 shims, so that may make a difference. I just view it as the nature of the beast (engine).

I'm 59,000 miles into my 2002 ST4s without a single rocker issue. My valves also only needed adjustment at 18,000 miles and they've stayed in spec ever since.

I'm beginning to suspect that rocker and valve issues depend a lot on how you ride the bike. I'm happy touring around at about 6,000-6,500 RPM with the occasional blast up in the 8,000+ RPM range. Those people that I know who have had rocker issues and need more regular valve adjustments, like to live up in the higher RPM range than I do.

[ST4R]

Originally Posted by Mike

...the extra displacement of the 4s is hard to argue with.

And the stronger cases, and the larger ports and valves in the heads.

[SS904]

When I was looking for an ST, I rode an older ST4 (99 I think) and the 03 ST4s that I ended up buying. Maybe not a fair comparison, as the ST4 I rode was a bit on the tired side... Also, I owned a 01 900SS at the time, and as you know, they have a "right now" bottom end. The ST4 was seriously lacking in that department. It felt weak down low, and over all, just loose (remember it was a bit beat). It actually turned me off on the 4V bikes for a bit as I expected more and that had been my first ride on one. Luckily I kept looking and came across the ST4s in almost new condition with only 3900 miles on it. Different story. Still maybe not as brutal as the 2V on the bottom end, but it just ripped everywhere else. It just felt so put-together and easy to ride fast that I found myself moving through the same roads I would push the SS on at a relaxed feeling pace with the ST4s, but I was going faster! I ended up changing the gearing to 14/40, and it now pulls like a freight train. I do not miss the SS's torque any longer, with this gearing, the 996 kills it in every way! I guess in reality either bike is nice, if you want the blue, go for it! It will probably be 100 times better than the beater ST4 I test road, but that 996 is a SWEEEET mil!!! I wanted red, as it is truly the faster color, but I ended up with the Senna colored ST4s because I just couldn't pass it up.

At the 6K valve check, I replaced both vertical exhaust openers @ $40 a piece. I also tightened all the clearances to the tight side of the spec. They were all on the loose side of the range to start with. I think (hope) that will make a difference. My 12K check will be next month.

The choice is yours, but I'd look for a ST4s if I had to do it again knowing what I know now. The ST2, 3, and 4 wouldn't even be considered. Yes, you can replace the shock, forks, wheels, swingarm, front rotors, and give it a good tune. That would get it up to spec, or make it even better than a 4s, but all that sounds like it would be more money and work than if you had just started with the 4s!

[Stopwatch]

Originally Posted by Mike

...the 4s just feels more nimble and compliant, probably due mostly to the lighter wheels and Ohlins shock but I wouldn't discount the contribution of the aluminum swingarm...

...I've replaced them with megacycle rockers...

...never offered in the slower blue color ;-) ...

Either bike can be turned into a wolf in sheeps clothing but the extra displacement of the 4s is hard to argue with.

Your comments surrounding the engine performance are predictable given the 9% boost in displacement from the 916 to the 996: a little more everywhere but probably not enough to make a difference.

Do I understand it that the ST4s came with an aluminum swingarm where the ST4 & ST2 were offered with steel? This would be a major upgrade and a significant place to drop some weight. I'd probably replace the wheels with Marvics (I've got them on my Supersport and really prefer the design over other aftermarket hoops), add a Penske or Ohlins shock, and go through the usual tuning on the fork.

The rocker issue seems blown out of proportion to me as well. It is interesting that there seem to be fewer failures on the ST's than the SBK's. The reality is that the replacement of the stockers with Megacycle parts fixes the problem forever and, relatively, isn't a major cost issue.

As far as color goes, well, I know I don't want red or yellow and the satin gray never hit me just right. Maybe with several hand-rubbed coats of clear it would work but then I'd have gloss gray, which was offered from the factory. I've got a soft spot in my heart for blue bikes as I had a pearl blue '87 Honda VFR700 for about 15 years and 90,000 miles (highly modified with HRC carbs, exhaust and engine parts, upside down forks, wide wheels, etc.).

Perhaps I should wait for the right ST4s, simply add lightweight wheels, and then I'd have the best of all worlds.

Thanks for all the input.

[BlueST2]

Originally Posted by Mike

The St4s was never offered in the slower blue color ;-)

That would be "robin's egg blue"...correct?

Originally Posted by PSsssp

As far as color goes, well, I know I don't want red or yellow and the satin gray never hit me just right. I've got a soft spot in my heart for blue bikes... Perhaps I should wait for the right ST4s, simply add lightweight wheels, and then I'd have the best of all worlds.

You could always have the ST4s painted Ducati blue. That would really offend a lot of the members here!