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Discussion Starter #1
One owner 2007 ST3s ABS with 46,000 miles that has been dealer maintained - until now. I'm using the Gates Carbon Drive app on an Ifone to measure belt tension on new belts from Desmo Times. I'm measuring the belts cold with respective pistons at TDC (verified with an endoscope). I measure the horizontal belt, then rotate 270 degrees counterclockwise to the crankshaft mark for TDC for the vertical cylinder. I record the values on a spreadsheet, then rotate the engine 10 revolutions and measure the belts again in the same manner. I'm getting some variance in the belt tension measurements, but average 109 hz for both the horizontal and vertical belt. This is within the new belt spec of 110 hz +-5. When started, the engine sounds normal. PROBLEM: When ridden, I hear a very noticeable turbine-like whine sound when above 3000 rpm that follows engine rpm and appears to be related to the new belts. I've had the belts changed at regular intervals and have not noticed this whine sound after a dealer service. What am I doing wrong? Thanks in advance for any wisdom that comes my way.
 

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What brand of belts are they? If they're CA Cycleworks, then the correct tension is 99.
 

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Discussion Starter #3
They are CA Cycleworks belts. I'll try 99 hz and see if that helps. Thanks very much,
 

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not uncommon for new belts to whine on the pulleys, check your tensioner and idler bearings for wear, any sign of it replace them, they will definitely grumble under load if they're worn.
Better to be too loose than too tight
 

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It appears you rode the bike some, I would go lower tension wise.

Specs for oem new belt is 110hz but for used belts is around 80hz if my memory is correct.
 

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I do get a kick out of tension specs. On the 4 Ducs I've done belts on, they've all been much much looser than spec upon disassembly, yet they ran beautifully! That stopped me from worrying too much about getting belt tension perfectly set. I err on the loose side.
 

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Part of the whine at above idle rpm's on new belts is the wearing in on the teeth - right? It goes away in a few hundred miles I think. Sacrificial rubber.
 

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the belt whine is not really a tension issue, more a belts slowly making the pullies the shape they want them to be issue.

if they're too tight it'll make a horrid bearing noise when it gets hot. i'd go 100 hz cold.
 

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Discussion Starter #10
UPDATE: I set the tension to 93 hz on both belts using the method described in my initial post and checked the pulleys. It still makes the same noise. As stated above, I've had the bike dealer serviced at the recommended intervals for the last 46K. It has never made this noise. The bike has probably had OEM belts installed for its entire life. The new CA Cycleworks belts may act differently than OEM belts. I don't know. I guess I can try lowering the tension even further to see if that works. The only other thing I can think to do if that does not work is reinstall the old belts and see if it still make the noise. If that doesn't work, I guess it will be time to jack up the tankbag and drive a new scooter underneath.

Thanks for your thoughts and wisdom.
 

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93 is too loose in my opinion. I wouldn't try anything less. Too risky a chance for skipping a tooth.
 

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the difference between 93 and 100 is pretty miniscule. the noise is not tension related. the ca cycleworks belts often do it for a little while.
 

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My ca belts whine a little at first. Goes away in short order. Nothing to worry about.


Sent from my iPhone using Tapatalk
 

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Discussion Starter #15
UPDATE; Reinstalled the old OEM belts, tensioned to 98 hz and reassembled AGAIN. Voila - no whine noise! Now I know that I don't have a bad bearing or pulley, and the noise is attributable to the CA Cycleworks belts. Apparently, CA Cycleworks belts whine when new. My decision now is whether to reinstall the CA Cycleworks belts or spring for new OEM belts.

Thanks very much for your thoughts and suggestions. I think I can take if from here.
 

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UPDATE; Reinstalled the old OEM belts, tensioned to 98 hz and reassembled AGAIN. Voila - no whine noise! Now I know that I don't have a bad bearing or pulley, and the noise is attributable to the CA Cycleworks belts. Apparently, CA Cycleworks belts whine when new. My decision now is whether to reinstall the CA Cycleworks belts or spring for new OEM belts.

Thanks very much for your thoughts and suggestions. I think I can take if from here.
I have used both the CA Cycleworks belts & the Ducati OEM. I feel the rubber is a bit harder on the CA belts, which may make them whine a bit. I just put CA Cycleworks belts on my 1000DS and don't notice any whine, but there is so much noise coming from our motors it is hard to tell. I feel the Ducati belts are more flexible and forgiving, so they may form to the pulleys a little better. Eevn tho Ducati belts are more expensive, I was told that Ducati parts are guarantee. I did have a Ducati part fail on my Monster many years ago, the dealer just replaced it with a new oem part at no charge. So that maybe a good reason to purchase OEM parts...
 

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the california cycleworks belts are generally closer to the theoretical sae tooth form than the ducati ones. in use that means they're a little "shorter" for want of a better term.
 

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Discussion Starter #18
I've got about 800 miles on the CA Cycle works belts and they still make a whining noise unacceptable to me. I just received a set of OEM belts and plan to change the belts again and install new OEM belts. I'm sure the CA Cycleworks belts are fine, they're just too noisy for me.
 
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