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Discussion Starter #1
Unless ducati comes out with a great replacement to the ST, I am thinking I may have this bike for a long time. If that happens there will come a time when parts get scarce. To prepare for this eventuality, I am thinking about getting a spare engine for my 2003 ST4s.

Actually the idea started with my most recent valve adjustment, when wrestling with replacing a bad rocker I thought how nice it would be to have fully adjusted heads ready to swap in every 6000 mi. Then I could readjust the valves on the bench at my leisure between servicings. It was a small step to thinking about having a whole engine ready for the day something more serious needs work on the bottom end.

Anyway, does anyone have a resource or know which 996 engines are interchangeable with mine? I saw some 2000 996 heads on ebay and they looked different than mine...
 

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Unfortunately, our ST4S (and the ST4) heads are unique. I believe the cam shafts are slightly lowered in the heads. A 996 track bike engine will not work. The belts for the ST4 and ST4S engines have 2 less teeth on the belts. And unfortunately (again!!) thatmeans that we have a limited source for belts. Bucci makes aftermarket belts for the 2V and the 996/916 machines (at a cost savings!), but I believe a pair of belts for us are over $150. The ST2 gents get to enjoy the thrifty Bucci belts!

The only other head that would work is the newer 748 engine. They have the same "lowered" cams like the ST4 and ST4S. But being smaller bore, I doubt the heads would work on a ST4S.

Oh, My ST2 had a bit more than 52,000 in it when I sold it. And there are gents that put mega-miles on the ST4S's. One gent in here did have a bottom bearing go at around 75,000 (Mark Turbo). And he's running again on the rebuild.

There's an interesting youtube recording of a gent that has a bad main bearing on a Ducati. Interesting watching and listening...a sound none of us ever want to hear!!!

I can dig the idea of having heads to "swap in", but I'd be more inclined to do this on a 2V, air-cooled engine. Less stuff to go wrong/leak. And I bet the head gasket "kit" price might be a major factor on the 4V
 

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Gary Eagan put on over 100k miles on his ST4. I dont know how many miles you ride, but it could last you a long time. The valve train beds in after 20,000 miles. I only check my valves every 12,000 miles now. Have 46,000 miles on mine.
Mike
 

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Discussion Starter #4
Good to hear some encouraging experience with long lived ST4s', also thanks for the run down on alternative engines Stick. Seems unlikely that I will find an ST4s engine for sale, but I will keep an eye open.

I have 42000 on my bike now, got it 3 years ago used with 3000 on it, so if they go 100,000 with good treatment I got some good riding years to go. Plenty of time for Ducati to get their act together!
 

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Unfortunately, our ST4S (and the ST4) heads are unique. I believe the cam shafts are slightly lowered in the heads. A 996 track bike engine will not work. The belts for the ST4 and ST4S engines have 2 less teeth on the belts. And unfortunately (again!!) thatmeans that we have a limited source for belts. Bucci makes aftermarket belts for the 2V and the 996/916 machines (at a cost savings!), but I believe a pair of belts for us are over $150. The ST2 gents get to enjoy the thrifty Bucci belts!

The only other head that would work is the newer 748 engine. They have the same "lowered" cams like the ST4 and ST4S. But being smaller bore, I doubt the heads would work on a ST4S.

Oh, My ST2 had a bit more than 52,000 in it when I sold it. And there are gents that put mega-miles on the ST4S's. One gent in here did have a bottom bearing go at around 75,000 (Mark Turbo). And he's running again on the rebuild.

There's an interesting youtube recording of a gent that has a bad main bearing on a Ducati. Interesting watching and listening...a sound none of us ever want to hear!!!

I can dig the idea of having heads to "swap in", but I'd be more inclined to do this on a 2V, air-cooled engine. Less stuff to go wrong/leak. And I bet the head gasket "kit" price might be a major factor on the 4V
The S4R should be the same head as well.
 

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Good to hear some encouraging experience with long lived ST4s', also thanks for the run down on alternative engines Stick. Seems unlikely that I will find an ST4s engine for sale, but I will keep an eye open.

I have 42000 on my bike now, got it 3 years ago used with 3000 on it, so if they go 100,000 with good treatment I got some good riding years to go. Plenty of time for Ducati to get their act together!
Here are some more data points for you. I have a 2002 ST4s. I got to 72,000 miles before I started to hear a 'whir' in the engine. Turned out to be a main bearing in the bottom end about to blow! My local shop rebuilt the engine with new bearings and seals and while they were in there, they replaced the pistons and re-coated the cylinders as well. I'm back on the road and up to 78,000 miles at the moment. :D

Oh and I see you are at 42,000 miles now. Do you have your wheel bearings checked at every tire change and service? I sure hope so. Are you still running the original bearings? If so, I advise you get them changed at your next tire change or service. My rear wheel bearing blew out at 42,000 miles! The shrapnel took out the wheel, the axle and the rear brake mounting bracket! I now get my wheel bearings changed every 24,000 miles as preventative maintenance. It's cheap insurance! In case you were wondering, there were no early signs that my rear wheel bearing was about to blow. It checked out fine upon inspection, every time! :eek:
 

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I'm with you on the st4s forever.

At 45k, I notice some foserous metal on the drain plug.
and I began to worry that the fuse was lit...

The bike has been running better and better from the day we brought her home in 05.
For me the only short comming of the bike is the wide ratio trany in the mountain.

Having located a 748 Trany, from the DUCSHOP
I went a head and rebulid it.
It was a good thing. The Main brgs were mostly dechromed..
=on the very short end of their service life.

With the Help of
DUCSHOP, www.ducshop.com
Cheshire Motorsports,www.cheshiremotorsports.com

She back on the road, with 53.8k on her.

with a coupe of mods.
the Close Ratio Trany,
Pistol SB Pistons and balanced crank,
996 intake cams, 11 degrees more duation

new valve guides and seals.
new bearings
new clutch and basket (47k on the orignal - not to bad..)

next, a power comander,
 

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Discussion Starter #10
Looks like the higher mileages can happen but also a theme of some bigger things needing to get done. Normal for any bike as it gets up in mileage. Some of the old BMW airheads go on for a long time, but they usually don't get the same level of enthusiastic riding as Ducati.

Thanks for the advice on wheel bearings Turbo. I just changed one on the back wheel, as it didn't feel as smooth as the other one. Based on your experience I will go ahead and change the others now. The idea of a wheel bearing destroying itself while at a good turn of speed is a bit scary.

Bill, I just looked and I think your engine is still up for auction. Am I right in thinking that after 2003 they changed the ST? I wonder if they changed the engines too? The ST4 engine is not the same as the engine on the ST4s, so I assume that even if it fit the bike, I would need to get the throttle bodies, ECU, airbox and maybe some sensor hookups to make it work? The heads would not likely be interchangeable either, too much to hope for...
 

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Bill, I just looked and I think your engine is still up for auction. Am I right in thinking that after 2003 they changed the ST? I wonder if they changed the engines too? The ST4 engine is not the same as the engine on the ST4s, so I assume that even if it fit the bike, I would need to get the throttle bodies, ECU, airbox and maybe some sensor hookups to make it work? The heads would not likely be interchangeable either, too much to hope for...
My late bike was an 04-ST4s. To the best of my knowledge, nothing about the engine was changed when the ST4s changed body styles in MY 04. The engine of my late 04-ST4s should fit an 03-ST4s such as yours.
 

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Discussion Starter #12
The one posted says its from an ST4 so either miss posted or from another bike. Good to know the later ST4s engine is the same, expands the hunting possibilities.
 

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Pinwall Cycles doesn't understand..

They don't realize that the motor they have is a very special thing. It is an ST4S motor. Not that the ST4 is not special, but it's just not an "S".

They are just a high-volume, "oh-well" kind of a bike wrecker. Just know for sure what you are getting beforehand..

I have a spare set of heads, and had a spare motor, but before I knew it, it was transformed into a spare bike. Dammit, how did that happen?
 

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I have a spare set of heads, and had a spare motor, but before I knew it, it was transformed into a spare bike. Dammit, how did that happen?
It is the work of the shop elves which come out at night while you are asleep.
 

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I am also on the ST4s forever bandwagon for reasons already mentioned. I purchased my '02 new and now have 45,000 + miles on it. It has never needed a shim or a rocker arm so I believe I got one of the good ones. These engines were designed for racing (and were very successful). I believe they are under-stressed in a touring application (the way I ride) and should last a long time.

Because I travel across the wide open spaces of the West a couple of times a year, reliability is important to me. In addition to regular maintenance, I am strongly considering having my engine rebuilt at about 60k miles. A blueprinted, balanced engine with new bearings, pistons, and maybe con rods would cost less than $4,000 from a highly respected shop. (Boulder Motorsports for me) That's a lot less than any new bike. I would also change the steering head and swing arm bearings. The bike would be off the road for a few weeks but I don't ride in the winter anyway.

Of course I will keep an eye on new releases from Ducati. You never know.

Jeff in Colorado
 

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I with you on the ST4s being my preferred ride for a long time but having spare parts around will be a good idea. As time goes by they will become more and more scarce (read more expensive). I just finished having my engine rebuilt at a little under 35k miles because of this:


I provided the replacement crank and rods out of a used ’03 engine I found and it still cost me between $5K & $6k. The shop (AMS) did an excellent job though she runs stronger now than she ever has. It’s not cheap to keep these babies running if they have major breakdowns but every time I take her out I know it’s worth it.
 

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I with you on the ST4s being my preferred ride for a long time but having spare parts around will be a good idea. As time goes by they will become more and more scarce (read more expensive). I just finished having my engine rebuilt at a little under 35k miles because of this:


I provided the replacement crank and rods out of a used ’03 engine I found and it still cost me between $5K & $6k. The shop (AMS) did an excellent job though she runs stronger now than she ever has. It’s not cheap to keep these babies running if they have major breakdowns but every time I take her out I know it’s worth it.
Man that looks ugly.

Do you know why they failed, or do you suspect poor bearings or cheap oil as culprits?

Craig:eek:
 

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Discussion Starter #18
Yikes! Seeing main bearings like that reinforces my desire to find a spare engine while there are still a few of them around! Glad you got her back on the road. If I can get an engine and a few of Bill's elves all will be good.

Guido, do you know that engine is an ST4s? If I was sure I would buy it. Brings up a question, are there any external visual clues that clearly differentiate the ST4 engine from the ST4s?
 

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WRW, if you can get them to give you the engine number you can tell what bike it is out of and the year of manufacture.

Craig, no one seems to be able to give a definitive answer to that, believe me I asked. Jeff says it looks as if it was run without oil, I have owned the bike since new and know that's not the case. Of course having oil in the case doesn't mean it's getting circulated but then I never got a low pressure indication either. It remains a very expensive mistery. I'm just glad to have it back on the road running strong, Thanks Jeff!
 

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Craig, no one seems to be able to give a definitive answer to that, believe me I asked. Jeff says it looks as if it was run without oil, I have owned the bike since new and know that's not the case. Of course having oil in the case doesn't mean it's getting circulated but then I never got a low pressure indication either.
Detonation from low octane fuel can hammer the bearings like that. It can surprisingly destructive and is not always obvious to the rider. Last summer I filled up with premium (93 octane) at a remote station on the west side of Vancouver island. About 10 minutes after fueling I noticed the engine was not as smooth as before. I pulled over to the side of the road and the engine died, something I don't think had ever happened before. I rode the 75 miles to the next town, drained the bad fuel and filled up with premium at another station. The roughness and vibration went away almost immediately.

I hope my bearings didn't get too hammered.
 
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