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 - 16 of 16 Posts

·
Registered
Joined
·
346 Posts
There are indeed a lot of threads on this forum related to belt tension. For the
1100DS engines the service manual calls out a pitch of about 85-100 Hz when the
belt is plucked and measured with an audio transducer. From my limited
experience with belt tensioning, this is a tighter setting than the 5 mm hex key
method (more like a 3mm gap between the tensioning roller and the belt). So
be careful with using the older methods... although slightly too loose is "better"
than too tight (the belt can overheat and shred if too tight), I had an issue
with my Hyper where it developed a strange midrange resonance you could hear
and feel when the horizontal belt got _too loose_ (like 6 mm gap loose).

A lot of people say to use a guitar tuner or tuner software, but my two guitar
tuners would not read the belt frequency well at all without an amplified
miniature (expensive) microphone plugged in to them... the built-in mic didn't
cut it at all. This is one of those jobs that seems really simple and gets complex
in a hurry when you consider the effects on cam timing, the fact that belt
tension changes with the position of the cams, the timing marks should all
line up correctly when the job is done, etc. Also, the two fasteners holding
the tensioners have different torque specs (20/26 N-m); I would use a good
torque wrench on them since guys have been known to snap them off. :eek:

BTW, re-check those belt tension frequency recommendations...; the factory has
a tendency to "change their mind" on the optimal settings and I don't know if
there's a new recommended tension setting out there already since the last
time I checked.
 

·
Registered
Joined
·
196 Posts
All the suggested guitar tuners were crap. Most of them didn't give the HZ frequency or you had to put in a chord, then it would just tell you it was "tuned". The others were so complicated that it would give you a headache. All worthless.

Then I found this.
http://www.mymusictools.com/test_tools_27/enable_guitar_tuner_16531.htm

Only thing I can say about it is, its simple. Hold a mike to the belt, strum it and watch the Hz frequency readout.
If I remember, I set the belt tension frequency to 108Hz. There is a current service bulletin floating around the forum.
 

·
Registered
Joined
·
208 Posts
All the suggested guitar tuners were crap. Most of them didn't give the HZ frequency or you had to put in a chord, then it would just tell you it was "tuned". The others were so complicated that it would give you a headache. All worthless.

Then I found this.
http://www.mymusictools.com/test_tools_27/enable_guitar_tuner_16531.htm

Only thing I can say about it is, its simple. Hold a mike to the belt, strum it and watch the Hz frequency readout.
If I remember, I set the belt tension frequency to 108Hz. There is a current service bulletin floating around the forum.


this is what i used too with an external cheap mic, worked well
 

·
Registered
Joined
·
592 Posts
i tried this and had no joy, all i picked up was the sound of my finger pinging the belt. I'd love to see some pics of the setup.

OR

with the right belt tension what size allen key will go under the pully?
 

·
Registered
Joined
·
243 Posts
i use the 4mm horizontal cylinder, 5mm vertical rule.just replaced mine- were very tight from factory-as were the fasteners( I know about these, having snapped one!)
out!
 

·
Registered
Joined
·
541 Posts
Discussion Starter · #9 ·
i use the 4mm horizontal cylinder, 5mm vertical rule.just replaced mine- were very tight from factory-as were the fasteners( I know about these, having snapped one!)
out!

Are you sure You didn't use 5mm for the horizontal and 6mm for the vertival? That is what the guy on the website used, but that engine is older.
 

·
Registered
Joined
·
605 Posts
That does not apply to the 1100 motor as the tensioner rollers are in different positions. A cheap lapel mic and demo guitar tuner software on a laptop worked fine for me. Of course you need one that displays frequency, and you should set the noise threshold up a bit (This may have been Pedro's problem). It should then read the belt vibration fine.
 

·
Registered
Joined
·
605 Posts
About 10-20mm from the belt. There is a thread with pics in the Hall of Wisdom.
 

·
Registered
Joined
·
196 Posts
i tried this and had no joy, all i picked up was the sound of my finger pinging the belt. I'd love to see some pics of the setup.

OR

with the right belt tension what size allen key will go under the pully?
Technique is everything. Hold your thumb down on the belt with it deflected and then release. Trying to fly your finger past it like your strumming a guitar or flicking it will never work. You can tell when it is picking up the right frequency from the belt and not your finger, as your finger wont produce the 110HZ frequency. When you hit the right tension, the frequency becomes very stable. It takes a few trys. Of course when I decided to go and set my tension, by the time I got things apart, it started to rain, then the house airconditioner kicked on and seemed to run forever, the neighbors decided to start a cook-out on there covered patio that resonated there drunken jibberish straight into my garage. I gave up and waited for another day.
 

·
Registered
Joined
·
243 Posts
I'm wondering if someone who's done the belt tensions the proper ( ie not my) way , could find the 'gap' with allen keys and let the rest of us know ?
I think its going to be around 3-4 mm based on what mine qas before the recent belt change- althought this is pure speculation.
thanks
jonathan
 

·
Registered
Joined
·
605 Posts
The problem with that method is its dependent on the force applied to the belt. Ideally you would have to spec a clearance at a given force, like that done to adjust Harley drive belts.
 

·
Registered
Joined
·
243 Posts
I understand , but , the belts have very little 'give' in them, so I'd have thought as long as you werent superhuman it'd be pretty reproducible.
 
1 - 16 of 16 Posts
Top