Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!
1 - 20 of 29 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter · #1 ·
I just picked up an 04 ST3 and the prior owner said the time was overdue to replace the belts.

Question: is this a DIY type of job?

I've read a few articles and seen a few videos and it doesn't look that difficult, but don't want to get in over my head as there are some important tooth / sprocket alignment / torque adjustments of note.

I am fairly adept at "some" mechanical items and have done a fair amount of basic motorcycle maintenance in the past.

Thanks

Chris
 

·
Registered
2006 ST3s
Joined
·
20 Posts
belts doable yes, what is the interval for valve clearance check?
 

·
Registered
2006 ST3s
Joined
·
20 Posts
it seems the belts are fragile, so they need to be done, theres a whole lot more work to get the engine bare enough to do the belts, than the actual belt replacement, also a handy tool to rotate the engine would be desirable to rotate the engine by hand to verify no contact of valves and pistons after you are done.
 

·
Registered
99' 996
Joined
·
366 Posts
It is a DIY job if you are mechanically inclined. Its not difficult, just some things that need paying attention to. Alignment is important of course, as is tension. But you can set the tension with an app on your phone these days. Otherwise its just about knowing how to properly use a torque wrench. If you want to dig in yourself or even if you are undecided and plan on keeping the bike and doing some maintenance buy the manual from Desmo Times. It is the bible for maintenance on these bikes.

How many miles are on the bike and how confident are you that the previous owner maintained the bike? Belts is a big one, so if they didnt do that what else wasnt done, or done when it was supposed to be.
 

·
Premium Member
Joined
·
250 Posts
I just picked up an 04 ST3 and the prior owner said the time was overdue to replace the belts.

Question: is this a DIY type of job?

I've read a few articles and seen a few videos and it doesn't look that difficult, but don't want to get in over my head as there are some important tooth / sprocket alignment / torque adjustments of note.

I am fairly adept at "some" mechanical items and have done a fair amount of basic motorcycle maintenance in the past.

Thanks

Chris
Easy to do, I have always done the belts on my ST3 and when I owned the 1998 900FE. The one tool that is good to have is a engine turning tool. In my opinion, it is easier to use the tool, than rotating the rear wheel.

The intervals for valves are every 6k, belts are every 2 years or 12k
 

·
Registered
Joined
·
69 Posts
Easy to do, I have always done the belts on my ST3 and when I owned the 1998 900FE. The one tool that is good to have is a engine turning tool. In my opinion, it is easier to use the tool, than rotating the rear wheel.

The intervals for valves are every 6k, belts are every 2 years or 12k
Agree (a) straight forward, and (b) engine turning tool make life easy

Life gets a little more involved in checking valve clearance, then a lot more involved if the valve clearances need adjusting.
 

·
Registered
Joined
·
48 Posts
This is a reasonable undertaking for someone who is mechanically inclined. Always good to have a shop manual and LT Snyder book to reference. And of course people on this forum are very helpful.

Going from memory you need to remove the seat, lift the gas tank(not remove), remove the right mid and lower fairing, remove the ECU (two clips), battery and battery tray. Once that is done the belt covers come off easily, the tensioners come out and belts can slip off. If you are worried about getting the timing right you can use a dot of white paint to mark where the old belts came off the cam sprocket and then transfer those to your new belts by counting teeth...I tried this and gave up. It was much easier to simply use the timing marks on the cam sprockets and case.

I purchased CA Cycleworks belts and they suggest a phone app and frequency (I think 110 Hz). This was a bit finicky but it's doable if you have a quiet place to work.

The key is to take your time, take lots of pictures and definitely drop $20 on the engine turning tool.
 

·
Registered
Joined
·
48 Posts
3-valve engine valve checks suck.
Because of the strong return spring on the exhaust valve? That was a pain..caused me to make a very small Bic in a valve seal. Luckily no issues during operation.

There is a tool made to depress the exhaust valve that apparently makes slipping much less likely.
 

·
Registered
99' 996
Joined
·
366 Posts
I dont see what would be harder but I havent had to do a 3v. And it isnt the exhaust spring, they exist on all of them. And yeah they are a pain. Shouldnt have to remove them though unless rocker replacement is necessary.
 

·
Premium Member
Joined
·
1,547 Posts
Really only a question you can answer for yourself….you have to be honest with yourself about your abilities and how well you truly understand about what your doing…that said it is not rocket science and there are mountains of examples and how tos out there to help you….it is not a difficult task, but the belts must be on exactly right, and the tension needs to be fairly accurate for longevity. Take your time, be certain the belts are installed without missing a tooth and roll the motor over by hand to ensure before you try and start it.
Of course the forum is full threads where folks changed their belts and it doesn’t run but they are sure they did it correctly and still got the timing off.🙄
 

·
Premium Member
Joined
·
250 Posts
I dont see what would be harder but I havent had to do a 3v. And it isnt the exhaust spring, they exist on all of them. And yeah they are a pain. Shouldnt have to remove them though unless rocker replacement is necessary.
The 3 v is a pain to do, my Ducati shop hates them too!
 

·
Registered
Joined
·
132 Posts
I had my belts done the first time by a lovely bloke called Arthur who runs Desmo Headquarters at Byron Bay.
Arthur happily let me watch which was very worthwhile. Much of the job is taking off the tupperware which really needs to be done in the right order. And also a big part is not to get frustrated by the number of fasteners that have to be removed and to make sure to refit them all nicely. So the idea is to whistle as you work, take your time, be happy and it's a really nice way to spend a couple of hours. So after I had watched Arthur I have always had a very nice relaxed feel when I take the fairings off. On the second belt change I did the job easily at home. I have changed timing belts on every car our family have ever owned, of several different makes , so the concept is similar on all of them.
I read a lot about checking the belt tension and finally came to the conclusion that it isn't all that critical, that snug is good, not too tight and not loose. It will stretch and become looser as you will notice when you remove the old belts. They look pretty slack after 20K so definitely don't put them on loose. I usually use white marker dots before removing a belt , a dot on the belt at the engine sprocket and the cam so if you do that you really can't go wrong. Of course if you go by the book and you find all the right marks and so on that's also a perfect method but sometimes it's hard to eyeball a mark on a sprocket against a belt so a white dot next to each will make it fit the way it came off.
I did try the frequency thing for belt tension on my phone but just couldn't get a reading. Maybe the later model phones work better than the I5. Hope this helps.

PS You do need to follow procedure as to removing each belt with both /all valves closed on that cylinder and then of course rotate to set the second cylinder and so on so a manual is really required to get it right the first time and every other time if you have a memory like a sieve as I do.. Please don't just mark belts and remove without following procedure or there will be trouble I can assure you.
 

·
Registered
2009 M1100S, 2003 Aprilia RSV Mille-R, 2x 1981Guzzi Monzas, IWL Pity, Piaggio Hexagon, PX Vespa
Joined
·
622 Posts
why exactly? i never did the 3V.
does the 5mm Hex Method work?
is that harder then 4V?
I recently did the belts on my M1100S, the frequency Method had the belt too tight. When the motor was warm, at idle, you could hear the cams breaking through the oil film in the head. A scrapping noise. In the end I used the HEX method and everything has been fine since. When the bike is at operating temp, the belt are REALLY tight. hardly any play in them at all.
 

·
Registered
Joined
·
36 Posts
yes chris, but that's a 2V.
buddy, duc specalist, prefer the hex method for 2v, but always the frequency on 4V.
so where's the 3V here?

The Fairing Shit is always the same on ST's?
on the ST2 that was... really...you have to remove everything for everything.:mad:
 

·
Just Visiting Your Planet
Joined
·
10,695 Posts
The 3-valve has two helper springs to overcome, so double the tension. Not so bad on the vertical, but damn awkward on the horizontal. I've been known to utter a naughty word or two. And getting the right spot to slide the rocker over is ridiculous. I just pull the shaft instead. Yeah, it's actually easier that way.
 

·
Registered
Joined
·
48 Posts
yes chris, but that's a 2V.
buddy, duc specalist, prefer the hex method for 2v, but always the frequency on 4V.
so where's the 3V here?

The Fairing Shit is always the same on ST's?
on the ST2 that was... really...you have to remove everything for everything.:mad:
Unfortunately the hex method doesn't work on the 3v. I took my time with my frequency measurements, as suggested by CA Cycleworks, and had no issues.

I also didn't have any issues sliding the rocker arms off the pin to change shims. But there are 5 months of non riding weather here, so I had all the time in the world to tinker and jiggle things to get them to work.

Turning the engine over slowly a few times by hand after you fit belts is also great advice that I forgot to mention.
 
1 - 20 of 29 Posts
Top