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Discussion Starter · #1 · (Edited)
Hi all,
I took some pics during my cam belt change today. First time I've done it myself and everything went fine. Pics show:
  • Left side spark plugs removal (no need to remove both sides; there won't be any compression with one front/rear pair missing, and the others are a bit harder to get at. No point making work).
  • Removal of crank end cap and insertion of crank turning tool.
  • Removal of plug caps on right side prior to cam belt cover removal.
  • Undo the seven screws holding the cam belt covers and you'll find it hard to remove the horizontal cover. Pull the oil line black sleeve quite hard and the oil cooler will tilt back on its mountings. The horiz. cover will now slide out easily.
  • Removal of timing plug so you can see the TDC mark.
  • Crank pulley timing mark matches the mark in the crankcase casting, with motor at horiz. cyl tdc (line is visible on crank through the timing window).
  • Mark up the old belts with Tippex. One dot at crank pulley, one dot at the cam timing mark and write on the horiz. belt 'T' for top and the vertical belt 'F' for front. You can just see my scrawled T and F inside the casings as well, to remind me which marks went where.
  • Slacken both bolts on both belt tensioners.
  • Remove old belts and carefully transfer the marks to the new belts.
  • Slide in the new belts and line up the dots. Apply a bit on tension to the belts to stop them slipping on the drive gears, and nip up the 4 tensioner bolts for now.
  • *** Turn the crank gently by hand a few times to make sure nothing is impacting anything else***.
  • If you feel metal hitting metal, stop; you've let one or both cam wheels turn a bit or your belt marking was off. Go back and double check everything again.
  • Once you've turned the motor over, the Tippex marks won't line up any more. Doesn't matter but if you want to get them back in line for any reason, just keep turning the motor over by hand.
  • Finally, using an iPod Touch with headphones and microphone, plus Cleartune app, to set the pitch of the timing belts to 110Hz+/- 5Hz (corrected from the original 140Hz which is apparently a Ducati manual error).
Torque up the tensioner bolts (I used 30Nm because that's what they came undone at).
Put all the bits back and you're done.
Hope this is useful.
Bill.
 

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140 Hz is too high. This is well known, and has been discussed extensively here. It was an error in the manual and there was a subsequent bulletin on it. The correct setting is 110 +/- 5 Hz.
 

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Discussion Starter · #5 ·
Correction...

140 Hz is too high. This is well known, and has been discussed extensively here. It was an error in the manual and there was a subsequent bulletin on it. The correct setting is 110 +/- 5 Hz.
OK - thanks very much.

Retuned belts to 110Hz.
 

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Well done! Thank you for the write up. Did you use Ducati branded belts? Mind me asking how many miles you had on the pair that came off?
Thanks,
Steve
 

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did anyone else that changed their own belt notice that after running the engine, the belts look like they are walking off the cam gears a little? I'm just wondering if this is normal, I don't recall them being like that when I took them off. I reused the belts since I was only repairing an oil leak, and put them back in the same spots.
 

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Discussion Starter · #8 ·
Belt change....

Well done! Thank you for the write up. Did you use Ducati branded belts? Mind me asking how many miles you had on the pair that came off?
Thanks,
Steve
Hi Steve,

Yes, I used Ducati branded belts.

My GT is a low mileage bike, having covered just 7,000 miles BUT it's three years old and this was its first belt change. The old belts were showing signs of wear - some fibres (kevlar?) were breaking free at the edges. They were also very slack.

I'll be sure to check them more often in future.

Cheers.
 

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did anyone else that changed their own belt notice that after running the engine, the belts look like they are walking off the cam gears a little? I'm just wondering if this is normal, I don't recall them being like that when I took them off. I reused the belts since I was only repairing an oil leak, and put them back in the same spots.
FWIW I believe when re-tensioning old belts like that the spec is 80hz. Not sure if being looser would stop them from backing off. Mine do not appear to be, but they were new Exactfit belts.
 

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I have 10k on my belts, last time they were checked was the 7.5k service. I decided I'd check the tension, I'll probably replace them later this fall and I figured this would be good practice. I checked using the sound tuning method and the 5mm key method. Most of my measurements were between 87Hz and 107Hz w/ a few outliers @ 55Hz and 128Hz ...it was kind of all over the place, but on averageI thought that was pretty decent...Id guess ~ 95Hz.

The weird thing was that I could only get a 2mm wrench between the tensioner pulley and the backside of the belt on the horizontal, maybe 3mm on the vertical. Is that 5mm or 110Hz standard for new belts only?
 

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according to LT Snyder, the 5mm key is NOT appropriate for the DS engines. 4mm key vertical, 1mm feeler horizontal. Probably means they need to be tighter. but he also emphasizes that people need to stop worrying so much about belt tension ;) it was a big deal in the 90s ducs, before they added kevlar to the belts, so there was a much higher chance of belt failure.

were you checking tension at TDC for each cylinder?
 

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Yep, both at TDC. I marked the belts as well as Horz and Vert TDC on the case...will hopefully speed things up when I do the new belts.

I used my Droid to measure the frequency, I think I need a new microphone b/c it was hard to get a good reading.
 

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Yep, both at TDC. I marked the belts as well as Horz and Vert TDC on the case...will hopefully speed things up when I do the new belts.

I used my Droid to measure the frequency, I think I need a new microphone b/c it was hard to get a good reading.
I really liked the measurement program from the guy who makes Ducatidiag. It's free and makes the job really easy:
Downloads

It's the one called "Courroies". It may be in French, but the software is pretty dead simple so you don't need to read much. Just need a PC laptop and a cheap mic
 

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I have read many instructions, but do not fully understand certain things. English is not my strongest side.

What is the reason to set the TDC (top dead center)?

Already ordered timing belts.
 

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So if I understand correctly, it is enough to match all 3 points: on crank gear, vertical and horizontal cylinder to the markings on the engine case/cover?
Plus the tick mark on the flywheel. And only then I can start to regulate both belts, right?
 

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It's the one called "Courroies". It may be in French, but the software is pretty dead simple so you don't need to read much. Just need a PC laptop and a cheap mic
I've done about 1/2 dozen belt changes since my post. Courroies is awesome, easy to use and very repeatable.

the timing marks relate to tdc horizontal firing. set the horizontal belt tension with the belts lined up. i do the vertical as per this:

if you don't understand it, don't do it.
I found that marking the pulley position in white for H-TDC and in red for V-TDC on both pulleys helped me.
 

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Timing belts replaced.
Application gStrings did not work too well on my phone, so I used Chromatic Guitar Tuner. Finger hurts ;)
I drove to a mechanic to tighten 4 screws with a torque wrench.
So in general, the old belts even though very old (SC 2007), did not look bad.
 

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