ST4 vs. ST4s – Ducati.ms – The Ultimate Ducati Forum

4 Jun 2015 | Author: | Comments Off on ST4 vs. ST4s – Ducati.ms – The Ultimate Ducati Forum
Ducati ST4 S

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.

Ducati ST4 S

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.

__________________

Mike Mullen

2002 STealTH Ducati ST4s (x2)

Ducati ST4 S
Ducati ST4 S
Ducati ST4 S
Ducati ST4 S
Ducati ST4 S


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