Just decided last weekend to paint the timing belt covers to change the ugly grey into some decent black. While having the covers of I checked the belt tension. The belts where changed some 6000 km ago. Using the allan key method I could easily slip an 8 mm hex through the idle pulley and belt. Easy fix apparently, I adjusted the mobile tensioners (cold engine) to such an extend a 5 mm hex slips through fairly easy, a 6mm hex with some more effort. Also the belts couldn`t be rotated more than the 45 degrees instead of almost 90 degrees before tensioning. Today I went to work, and noticed a whining sound coming from the tensioners the moment the engine heated up, especially between 2.500 and 3.500 rpms. I know, Ducs can make noises but this happened right after I adjusted the tension of the belts. Coming home I checked the belt tension (hot engine) and the tension was quite stiff, couldn`t lift the belt from the tensioners. After cooling down the belt had its 5/6 mm gap again, the allan keys came through. Checked the bearings manually, they rotate free, no free play or other indication that they might be shot.
Question, is this normal, that with a hot engine the tension is zero, i.e. no play at all. Is the 5mm hex method the proper one for an S2R 800 (Reading all the topics about this in this forum, I should think so).
Please opinions, loosen the tension a bit or just drive. Could the bearings be shot after 16.000 kms?
Mark the red dots, factory???
(https://lh6.googleusercontent.com/-WAsvTLDnSu0/USIP4GTThoI/AAAAAAAAAsE/h5TTQWfXXKg/s800/IMG_1323.JPG)
See the gap
(https://lh3.googleusercontent.com/-xMIhbTNyfm4/USIP9Rv7eJI/AAAAAAAAAss/-2RczycfW_U/s800/IMG_1328.JPG)
The 5mm allan key method
(https://lh6.googleusercontent.com/-CRb_ljo5wY8/USIQCoY5YoI/AAAAAAAAAtY/L2XJI6jz59M/s800/IMG_1333.JPG)
(https://lh3.googleusercontent.com/-fRZcuXfK3VI/USIQD0dxiBI/AAAAAAAAAtg/o-9uoBLg3pY/s800/IMG_1334.JPG)
Actually I started painting this...
(https://lh6.googleusercontent.com/-CYOrKjbgVno/USIQPNov4bI/AAAAAAAAAuw/1HQU85Z22kU/s640/IMG_1344.JPG)
And than this...
(https://lh4.googleusercontent.com/-EK0D8J9NvR8/USIQGtX300I/AAAAAAAAAt4/AFV4OWF816c/s800/IMG_1337.JPG)
Resulting in this, with which I am fairly happy...
(https://lh5.googleusercontent.com/-xA3eXSN6oYc/USIQSBiiTLI/AAAAAAAAAvA/iK65_YZJQPk/s144/IMG_1346.JPG)
(https://lh5.googleusercontent.com/-v47TOlnpC6A/USIQTG8CEPI/AAAAAAAAAvI/RCZ1nZ701DI/s800/IMG_1347.JPG)
The belts getting tight when hot is normal. That's why you leave play when cold.
Check your pulley bearings. If you feel any roughness it's worth the replacement. If they're smooth, then you're just hearing a different sound from the load on the bearing.
i checked the bearings and they feel smooth without any hiccups. I`ll just drive for a while and keep a close eye on the bearings... Thx ducpainter
You may also want to try the audio method of tensioning. If you have a guitar tuner with a mic, or a smartphone with a tuner app, tune your belts to 110 Hz. Pluck the belt on the long part on the side with the tensioner. Doesn't have to be exact, and it's kinda fun to say you're "tuning" your Ducati to A(-1).
There is an iPhone app made by gates that will pick up and read the frequency from your belts by plucking it like a guitar string and holding your iPhone near it.
Personally, I've found both sonic and IR measurements to be less repeatable than the tried and true allen key method.
You can vary the reading by the strength of the pluck. The factory uses a machine that also plucks the belt which makes it repeatable..
Quote from: ducpainter on February 18, 2013, 08:09:45 AM
Personally, I've found both sonic and IR measurements to be less repeatable than the tried and true allen key method.
You can vary the reading by the strength of the pluck. The factory uses a machine that also plucks the belt which makes it repeatable..
What about a digital fish scale?
Quote from: memper on February 18, 2013, 04:36:26 PM
What about a digital fish scale?
What number/value do you use?
Granted, there is some variance in the 'feel' of the allen key method, but IMO it's much simpler and proven.
Not entirely sure but I recall seeing in my Haynes manual, in the maint section, a picture of the guys hands holding what looked like a fish scale. Didnt read that area to see if any lbs are mentioned because I dont own such a device.
Iirc the Haynes manual mentions something like 4.5kg or 10lbs pressure when they tested the factory tool. The fish scale method isnt always practical with the engine in the frame depending on the model.
I use a fish scale, the allen key method and the 45° twist. I really do like the allen key method the best and I back it up with the 45° twist. I still have to be careful not to press too hard with the allen keys though.
Whereabouts should one twist the belt? Different parts will give different tensions
I did doublecheck the tension with the 45 degree twist at the longest freerunning part of the belts. All signals are green, 5/6 mm allan key method, 45 degree twist, bearings free running no play or rough feeling. Still don't like the whining sound which wasn't there before ???.
(https://lh5.googleusercontent.com/-_JcqLFoKTS4/USIQEwWvfHI/AAAAAAAAAto/XULAGBkZMmU/s800/IMG_1335.JPG)
In my _limited_ experience, retensioned (tightened up) and new belts whine for a while.
It's good that you ruled out over-tensioning and pulley bearing roughness.
I believe chris posted previously that whine can be normal. Couldn't find the exact post.
Expect the whine to diminish over some (?) miles.
Ride and enjoy! [Dolph]
**edit** You did rotate the motor to the proper position(s) prior to tensioning the belt(s), didn't you?
BK
**edit** You did rotate the motor to the proper position(s) prior to tensioning the belt(s), didn't you?
I'm going to check mine this weekend, what is the proper position of the motor when I check?
Thanks
Quote from: MostroS2R on April 18, 2013, 11:18:33 AM
**edit** You did rotate the motor to the proper position(s) prior to tensioning the belt(s), didn't you?
I'm going to check mine this weekend, what is the proper position of the motor when I check?
Thanks
You want to check tension with the cylinder for the belt you're checking at TDC.
Quote from: ducpainter on April 18, 2013, 03:04:46 PM
You want to check tension with the cylinder for the belt you're checking at TDC.
Pardon my newb question... but why does TDC matter for belt tension? Does the tension on the belt change depending on where there motor is positioned?
Quote from: joshuajcrouch on April 18, 2013, 04:29:14 PM
Pardon my newb question... but why does TDC matter for belt tension? Does the tension on the belt change depending on where there motor is positioned?
I believe the theory is the cam is completely unloaded at that position due to any rotational force from the closer assist springs being removed.
Quote from: joshuajcrouch on April 18, 2013, 04:29:14 PM
Pardon my newb question... but why does TDC matter for belt tension? Does the tension on the belt change depending on where there motor is positioned?
yes.
needs to be at tdc firing.