If you set belt tension on a 1000/1100 engine with the sonic method,
which Allen key size fits between belt tensioners?
The subtleties in adjusting in accordance to a harmonic are so slight it's almost comical thinking there's a shortcut...but...the belt isn't going anywhere and if it's a bit too tight your going be annoyed into loosening it up anyway
Just get a guitar tuning app...rotate the engine so the cams are free and start strumming like your warming up for a desmo concerto
5mm horizontal, 6mm vertical same as all the others. Done it both ways on 620, 1000ds, and 1100.
1000/1100 motors .
Rear 4mm Allen key.
Front 1mm feeler gauge. ☆
The belt pulley locations are not symmetrical between cylinders compared to the smaller motors.
☆ Some give a little more on the front like 2mm on a feeler gauge. It may depend on your feel and how strong your hands are. Developing arthritis has probably made me more accurate [laugh]
Then I twist the belts for that 45 deg twist test, then I warm the bike up and note how much tighter they get with thermal expansion of the motor (more than you think). I do this double and triple checking due to not having the Harmonic tensioner.
As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt.
I use LT Snyder's, bikeboy's and Speeddog's specs.
Did some measurements last night w new belts.
Gates Carbon Drive app no readings, PanoTuner worked ok.
Hard to get consistent results f sure.
The issue when comparing Hz-Allen is snugness me think, f e medium snug 2mm is a
little tighter snug on 3mm, too inconsistent to get repeatable result etc. You simply cannot say f e 3mm Allen equals X Hz.
Think I`ll go w koko`s advice from another thread about 1100 engines
and set 3mm HZ & 4mm VE. Snug. ;)
I tend to use Exactfit belts and oem. I often set on the looser side of good, if you get my drift. The belts really do tighten up a lot on a hot motor.
Rent a harmonic tensioner from ducatitoolrental.com. Easy to use and get correct tension. No guessing.
Quote from: Armor on April 28, 2021, 06:36:42 PM
Rent a harmonic tensioner from ducatitoolrental.com. Easy to use and get correct tension. No guessing.
Not so easy for some of our overseas members.
Quote from: koko64 on April 25, 2021, 11:33:01 PM
As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a bearing or snap a belt.
;D
Quote from: koko64 on April 25, 2021, 11:33:01 PM
1000/1100 motors .
...Then I twist the belts for that 45 deg twist test, then I warm the bike up and note how much tighter they get with thermal expansion of the motor (more than you think). I do this double and triple checking due to not having the Harmonic tensioner.
As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt.
I use LT Snyder's, bikeboy's and Speeddog's specs.
put a couple of new sets of cam belts on an 800 and 1K ds; as you know not good to overly tighten belts. Initially using the Allen key method; checking to see that the "As an older guy said here once, tight enough to not skip a tooth and loose enough to not wreck a pulley or snap a belt." ;D
Using the 45 deg when hot method; check and see how snug; then just loosen the tensioner and tighten the tensioner to on the loose side of snug while still hot (while minding the hot exhaust pipe ... )
... let me know if I'm missing something in that thinking.
did try plucking the belts and listening to the harmonics; I in fact spent a lot of time plucking the belts, listening, thinking um-ming and scratching my head, chasing my tail, ... and went with the above.
What readings did you get?
Did you use the 5 & 6mm Allen key method on the 800 and 4mm & 1-3mm method on the 1000?
Some thoughts. Do you pull the belt away from the pulley a little when passing the Allen key through or just push it through? How heavy handed are you? How much force do you use and how much drag do you feel? Also I have found the Exactfit belts more supple and the oem a little stiffer to handle. It's a bit like adjusting valves, you develop a feel and confidence over time. Honestly, there many belts out there adjusted a bit too tight or a little loose and working fine and while it does effect cam timing, how many bikes come from the factory with perfect timing?
Some people will get a shock when they check the belt tension on a hot motor. It explains why the factory changed its tension specs on the 1000/1100 models. So while it's easier on the 400-900 models, I spend twice the time setting the tension on 1000/1100 models. I thought about buying the tool, but I think like with any tool or equipment, the operator is still a factor.
I have used the "proper" harmonic tester on the 1100 motor a cople of times (borrowed from a friend) and was surprised at how tight the belts were adjusted to the recommended frequency. Nowhere near any allen key test gap as I remember it.
I think next time I'll adjust the belts tight on a warm motor with the cams free, and see how that feels when the motor is cold.
Judging from the big difference you can see in belt tension on motors depending on how long since they were adjusted, and who adjusted them, etc, there seems to be quite a wide window before anything bad happens.
I'm not trying to say it's not important, but within sensible limits it seems to work quite well, nothing to lose sleep over. Beeing consistent and keeping track of the status is key for me.
Quote from: koko64 on May 01, 2021, 12:08:08 PM
What readings did you get?
Did you use the 5 & 6mm Allen key method on the 800 ....?
Some thoughts.....just push it through? heavy handed;
.... Honestly, there many belts out there adjusted a bit too tight or a little loose and working fine and while it does effect cam timing, how many bikes come from the factory with perfect timing?
Some people will get a shock when they check the belt tension on a hot motor.
above is generally what I did with a 5mm both cam belts on a 800 ... 1ks different; when I had it in for an expert mechanical tune after a rebuild; the expert mechanic race tuner mentioned he thought the belts were loose on the old where I had them set; I remember fussing with this; think it was 5mm / check while hot method. I gave him new belts he installed never second guessed him. Bike ran way better after he tuned it; expensive service but worth piece of mind.
Harmonic tension is that elusive quirky Duc thing that if you don't do this all the time; I think its easy to F up. Wouldn't recommend to a back yard mechanic; even if you can tune a guitar (I can harmonically tune a guitar no problem; very accurate when you get the hang of it).
Sorry if I expressed myself poorly. I set the belt tension cold, I finger check them hot for some "give" to not stress the belts or bearings. So the Allen key setting is cold. The 6mm is to not fit but the 5mm goes thru on the 400-900 bikes. The 5mm goes thru then the 6mm should not go thru, if it does the belts are too loose.
I'm quick with my own bikes but double and triple check customer bikes. ;D
Quote from: koko64 on May 02, 2021, 10:34:58 AM
I'm quick with my own bikes but double and triple check customer bikes. ;D
Except for the customer bike bit (I don 't have any), I'm the same :-)
Brad`s take on 1kDS:
https://www.youtube.com/watch?v=wDonQSQiuG4
So, at last, l caved in and did it the sonic way.
Gates gave me 100 Hz (occasionally...) and
Allen & feeler gave 4mm VE & 1mm HZ.
Bit better throttle respons than old belts
setting (they were a bit off, 4mm on HZ f e).
Old dog finally overcame the 900 oldie way. ;)
[thumbsup] :)
Quote from: greenmonster on May 03, 2021, 07:58:17 AM
Brad`s take on 1kDS:
Nice to see an expert at work; thanks for posting that;
Brad makes it look soooo easy; see how he's having troubles picking up the sound on the tuner app .... an he doesn't like the 5 mil hex method ... interesting.
Loose side of snug when hot would be interesting to hear what brad would say to that ...
I think checking with a hot motor is insurance to ensure the belts aren't dangerously tight due to human error. Human error can occur with using or interpreting the reading of any tool.
It reminds me of setting drive chain tension on a side stand then checking for sufficient play with a rider, just to be sure.
I've tried some frequency apps but never managed to get consistant results, only managed to get sore fingers from all the plucking, really. After watching Brads video (thanks, Gerth :-)) I tried the Gates app, which seems to be slightly better than the others I've tried, the results still vary rather wildly. It may be just me, Brad seems to get consistent results, but that does not help me.
Also, trying to adjust whatever tension you have is very difficult to do consistently, it's often too little or too much, and I also don't like the Allen key method, it's also very difficult to do consistantly. Since I like mechanical solutions (as opposed to electronics ....), I figured a repeatable mechanical solution would be nice. So I've machined a collar with 4 mm wall thickness to fit over the tensioner roller, sort of a "consistent 4mm Allen key":
(https://live.staticflickr.com/65535/51159143005_34e52ce0ba_k.jpg) (https://flic.kr/p/2kWKYRK)2021-05-04 20.12.04 (https://flic.kr/p/2kWKYRK) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
With this over the roller, it's easy to pinch the rollers towards oneanother, and since the belt is very stiff longitudinally, I don't think it's too sensitive how hard the pinch is.
Anyway, with the belt tightened against the collar and the tensioner torqued, the app gave me reasonably consistent readings (with collar removed, of course), but still varying between some 80Hz to 110 Hz.
The belt is slightly lose to my taste, so I'll make another one with maybe 2.5 mm wall thickness, and see where that takes me.
Of course, I don't think this is the holy grail of belt tensioning, but I do think it will at least make it easier for me to get the belt tension consistent.
Quote from: MonsterHPD on May 04, 2021, 12:44:15 PM
1- I've tried some frequency apps but never managed to get consistant results, only managed to get sore fingers from all the plucking, really.....
2 - ..... very difficult to do consistently, it's often too little or too much, and I also don't like the Allen key method, it's also very difficult to do consistently. .... a repeatable mechanical solution would be nice. So I've machined a collar with 4 mm wall thickness to fit over the tensioner roller, sort of a "consistent 4mm Allen key":
.... but still varying between some 80Hz to 110 Hz.
The belt is slightly lose to my taste, so I'll make another one with maybe 2.5 mm wall thickness, and see where that takes me.
1 - ex-zactly! ditto its inconsistent ... and ya all get sore fingers too.
2- Collar spacer is a great idea; just remember different engines & cams on the same engine have different hex spacers to get the right tension;
so I guess you'd need 2 for a 1k ds; Vert 3mm & Hor 1mm? to dial that into spec.
... thinking it'd be better without the inner lip; not too tight fit over the roller; something that's easy to slip on and off when the rollers snugged in place.
I have not delved into the different specs, but the HYM1100 is 100Hz on both cylinders (but 140 on new belts ...). I have no idea how well this might work in the end, but I will do some different collars and see where that takes me.
The lip is there to help pull out the collar from under the belt, but it was easier than I had expected. Might come in handy for the vertical cylinder since that roller is pretty well hiddden behind a fram tube. Easy to remove, should that prove the better option :-)
Really cool tool. You could sell thousands.$$$$$ :D
Quote from: koko64 on May 04, 2021, 10:30:31 PM
Really cool tool. You could sell thousands.$$$$$ :D
;D
Free for anyone so inclined to make their own and experiment with frequencies and sore fingers :)
Not much of a businessman, I'm afraid .... [coffee]
Well,
even a potentially ggod idea can have it's flaws .....
(https://live.staticflickr.com/65535/51158986162_28f397c53b_k.jpg) (https://flic.kr/p/2kWKbey)2021-05-05 16.23.13 (https://flic.kr/p/2kWKbey) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
The sleeve will need some more maching time before it will fit the vertical cylinder, the belt cover is very tight here. But I think even with enough machined away on the sleeve it will still be sufficiently well guided on the fixed tensioner roller to make sense.
Quote1 - ex-zactly! ditto its inconsistent ... and ya all get sore fingers too.
+10.
On the 900, l put a 5mm Allen 45 degrees across pulley,
then tighten. Pretty consistent.
Quote from: MonsterHPD on May 05, 2021, 09:49:55 AM
Well,
even a potentially ggod idea can have it's flaws .....
The sleeve will need some more maching time before it will fit the vertical cylinder, the belt cover is very tight here. But I think even with enough machined away on the sleeve it will still be sufficiently well guided on the fixed tensioner roller to make sense.
youve com up with a neat simple solution; flaws can always revised; yep looks like very tight spacing of roller to that flange; maybe; no lips and just cut er in 1/2!
For now, I cheated and used a ca 2mm stack of feeler gauges.
I'll try to machine the sleeve so there's a little more than half left, soit will stay on the roller without me holding it. Let's see if that works :-)
I would have a Ducati dealer tighten the belts withe their harmonic tool and them make your tool to match. You may surprised how tight the belts are. My opinion is that the motor runs better with tight belts. You can feel the difference.
Yes that ensures timing accuracy, however, that assumes the timing is correct from the factory, which it often isn't.
Quote from: Armor on May 11, 2021, 12:47:09 PM
I would have a Ducati dealer tighten the belts withe their harmonic tool and them make your tool to match. You may surprised how tight the belts are. My opinion is that the motor runs better with tight belts. You can feel the difference.
As mentioned, this is basically what I did, and as you point out, I was also surprised at how tight the belts were. I've now modified my sleve to 2.5 mm, I'll check where that takes me next time I have to belt covers off.
Quote from: MonsterHPD on May 12, 2021, 06:07:59 AM
As mentioned, this is basically what I did, and as you point out, I was also surprised at how tight the belts were. I've now modified my sleve to 2.5 mm, I'll check where that takes me next time I have to belt covers off.
What spec ate you using?
Well,
to be honest, I don't quite remember what we used at the time, the instrument owner was present and guided, but it was in the 100Hz to maybe 120 Hz range, new belts. I think the HYM1100 spec is 140/100 Hz new/used belts. Anyway, the belts were quite tight, no convenient way ro get a 5 or 6 mm allen key through. Not impossible, but not convenient or "gagelike".
At some point Ducati went to a lower frequency on some models due to bearing failures. I don't think Ducati uses 140 for anything at this point.
Quote from: howie on May 12, 2021, 04:26:17 PM
At some point Ducati went to a lower frequency on some models due to bearing failures. I don't think Ducati uses 140 for anything at this point.
That's interesting ....
I went to a track day last friday, my first real ride for this year. The first 2 stints I rode the m800, and after getting used to all the normal noises, I thought I heard one I did not recognize ... If i reved the motor at standstill, I thought there was like a WZZzzzzz.... noise when the revs went down again.
I took off the covers to se if everything seemed OK, which it did, but on the still-warm motor, the belts were quite tight.
When I got home, I did some checking and experimenting with the modified sleeve, now 2.5 mm wall thickness:
(https://live.staticflickr.com/65535/51189133343_656e00b688_k.jpg) (https://flic.kr/p/2kZpFWx)20210518_103706 (https://flic.kr/p/2kZpFWx) by torbjörn bergström (https://www.flickr.com/photos/125016045@N02/), on Flickr
It actually is possible to get very different levels of tension on the belt, "tight" can be very differently tight, but snugging up the tensioner against the sleeve, slightly tightening the fulcreum bolt, the using a small hammer and a drift on the movable tensioner bracket to tighten the belt, there is now a slight gap between the fixed roller and the belt with the sleeve removed.
With the Gates app, that translated to somewhere in the 140 Hz range. Measured with the allen key method, that's tight om the 4 mm ky recommended by Kämna at tthe service course I went to many years ago.
Doing the same procedure again, but sligtly less tight, gave reasonably consistent readings in the 120 Hz range (with occasional readings of 270 Hz, 55 Hz etc, etc, ....), so that's where I left it for now. Depending on if I hear something or not on the next ride, I might either try even looser belt, or change the bearings (which all felt fine, no rough spots or noice). If there's a noice, I'll probably change the bearings anyway.
Interesting. There is a certain bearing whine sound that a hot motor can give that will tell you to double check belt tension.
... I'm learning some new stuff here ... didn't think belt tension could affect timing / performance so much; then again the professional tune I got done had a noticeable improvement in performance.
Rechecked new belts after about 750 kms.
Belts look good, no hints of wear. Belt tension on warm engine same as cold,
new belts have stretched a bit? Only checked w Allen & feeler.
Belts w correct (well... ;) ) tension gives engine bit snappier and easier to start than before.
So the 1/4mm or around 100 Hz method seems right IMHO.
[thumbsup]