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I have a a 2013 SF 848 with the original belts about 3200mi on it (sorry friends I'm fixing it). Track use only. I'm in the process of changing the belts... The current F is 54hz +/-5 on both belts using the carbon drive app. Just really checking out of curiosity before it take them off. I'm all for doing procedures correctly (I have the book, read through) however, I feel like this is a joke. Most of these types of tensioning tasks I've done with a force gauge, (i've used a spectrum analyzer pretty extensively and frequency analyzer a few times- but I didn't have to buy it). I'm more familiar with eyeballing it but with those procedures I tend to be more familiar with what's going on. I'm familiar with much more complicated items but looking for some loose guidance as I finish this up, and set the tension, errrorr on the side of loose. I was thinking of just using a 10mm wrench between the cams to 'certify' good. Any thoughts, jokes, criticisms?

My biggest reason for asking is safety. I only ride on the track I absolutely love it, I don't want to ruin anyone's day out there, or mine. Plus, I have 4 kids to feed so I need to make it to work Monday and with at least the motor together. Lastly, I have transitioned to Ducati I won't buying any other bike manufacturer, I'm truly a follower now and will be wrenching on the entirety of its future, so I'm looking forward to learning more...

Best Regards,
Mickey

Thanks to all of you who share your wisdom, I spend a lot of time on here learning. Thank you!
 

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Setting tension this way is a legitimate method, and in many cases more accurate than a force gauge because it mostly takes the operator out of the equation. Many modern supercars spec this way, and pretty sure the later Ducs that is what is recommended by the factory. Even industrial equipment is primarily done this way.

Make sure you dont have a lot of ambient noise, take your time and set it and dont stress on it. Not doing them at the prescribed intervals is far greater a safety issue than how you set the tension.

 

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I set my belt tension using the Pano Tuner app. It's very simple to do, just make sure that the piston is at TDC for the corresponding belt when you're setting the tension.
 

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1994 900SS CR, 2002 998 Trackbike
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I use "spectroid" on an Android phone for my Testastretta. It shows you the whole spectrum of frequencies that the microphone picks up, and you can clearly see the peak in the spectrometer of the belt resonating above the background noise when you pluck it. The peak shifts very accurately and clearly when you change the belt tension.

Based on this i have no doubt that guitar tuning apps or the gates app can pick out the frequency as well and give you accurate results. Just make sure you pluck the correct spot on the belt, and with the cylinder at TDC.


I do my 2V 900ss by feel, or by the 5mm/6mm Allen method, because that's been the traditional way for those motors for a long time, and the frequency method doesn't seem to work as well on them.
 

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I have used the Gates app because of the convenience of having it on my phone but I always have better and more repeatable results with the free belt tension app here:


There is a lot less extraneous "noise" with the laptop using a cheap lapel mic than I get with any of the many phone apps/guitar tuners I have tried. It also seems to lock on the frequency better. If you look at the sample screen shot on the JPDiag website you see a very definite peak on the primary belt frequency the mic is hearing. Older engines may be just fine with the allen key method but the DS engines and the 4 valve stuff I think need to be done by the belt frequency method to be accurate. Then again it's not rocket science and as long as the belts are not too tight it'll probably by alright...but a failed belt will really cramp your style. And if you are only tracking the bike and bouncing off the rev limiter all the time it becomes more critical that the belts are "right".
 
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This again

All I've ever done on my 4 aircooled 1100's with a combined 60k miles between them is push the tensioner with my index finger to tension the belt & snugup the bolt

Finito!
Never had any issue. Its just a Gilmore belt driving a cam with absolutly no load whatsoever (no valve springs)

All my dry sump race engines have a hellova lot of resistance spinning a 5 stage pump & that belt can be twisted 90° between pulleys NEVER had a problem in 45 years & they spin 20% faster than the crank rotating 9000rpm

Carry on
 
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Out of curiosity I checked my belts several ways just to know the outcome. I originally set them with the N Track Tuner app on my phone as Belter suggested. I checked that against my Harley Davidson belt tension tool ( same tension spec) , Harley tool matched . Then checked with an Hex key, which is subject to “feel” , still checked good. So , I surmised that it doesn’t matter how you check them, as long as you check them. The cam belt is a big rubber band. Close enough is just right.
 

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All I've ever done on my 4 aircooled 1100's with a combined 60k miles between them is push the tensioner with my index finger to tension the belt & snug up the bolt
while this is pretty much the way it works for all models both 2v and 4v (you can see when the slack goes out of the belt as you roll the adjuster around), people confuse methods and techniques and advise on the model they know, without realising techniques vary. 5mm hex key on the horizontal belt of the ds or st3 gives a very loose belt for instance.
 
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