[belter]

did some self shot and edited videos on the ds style head engines.

Ducati 7mm closing valve shims

 

[dadouzzu]

Hi Brad, thank you for the videos.
Well done, very informative.

I found that rotating the crank few turn and re-measuring the belt tension you can find some tight spot.
On 900ie i can measure 100hz in one spot and maybe 120hz 5 or 10 turn after. (Oem belts)
Did you check this or i am just too peaky ? Better set to average 110hz or 110hz on tight spot?

Also for closing clearance, when is near zero, rotating the closing shim 1/4turn and re-checking cam drag i can find some tight spot that desapperar when i furter rotate the shim.
Did you check and use a shim like this or go with a shim that has no drag in every position?

 

[belter]

if i'm doing a sonic/acoustic belt setting i turn them over a heap of times, certainly 5 or so rotations between every adjustment, and sometimes i check them every rotation once i'm done just to see what sort of variation i get. generally they are quite consistant, and i usually go for a "no more than" setting. if you notice a lot of variation, maybe mark the belts and pullies and see if it's consistant with a position of either.

i think the spinning of the shims i would do without even thinking about it. if i saw a lot of variation i'd replace it.

 

[dadouzzu]

Ok, now i can tell to my wife i'm not too peaky ??.
70 t belt in 18t pulley means 36 turn to have the belt in the same position..
Anyway I have re-cheked it (30km done) and found 100hz pretty consistent, so i didnt mark it.

I looked at cam locking slot, with the crankshaft aligned with flywell mark

Seems that someone as been here and probably there is bit of retard on both cilinder timing.
Did you find this slot and also the flywell mark not accurate enough on this engine?
Loosening the pulley screws without the locking tool can damage the belt?

Maybe its time tu buy a proper degree wheel, dial gauge base and follow your video

At least when covid-19 ? will go away, and shops re-open

Thak you

Edit: corrected some thoot numbers.

Maybe the cam timing is related to measured compression?

Low compression m900ie

Hi, i repeated a compresion test: 105psi front 95psi rear Same hot or cold, wide open throttle. 44000km On previous test at 29000km i had exactely the same numbers. Almost no oil consumption over any change interval (6000km) Valve clearance always 0 for closer and 0.10mm opener. Cam timing not...

www.ducati.ms

 

[belter]

you have a trad 2v, not a ds. i don't use sonic belt tension setting on them, i just do them by feel. there's other videos about them on the mike's machines channel.

i've never used the locking tools on one of them either. cam timing can influence the cranking compression - often i'd see one go from 130 to 150 on a 900 going from 113 to 106 maybe. that sort of thing. give it a leak down test to see if it is a static thing. if you pull the belts off you don't need to worry about finding tdc.

 

[ducvet]

The pulley locking slots are for allowing a monkey to set belt timing correctly. It is NOT true cam timing.

Expect it to be off some times but unless someone has done something out of the standard (cams, or other engine work) it is a "close enough" setting. If someone has degreed the cams expect it to NOT line up when done most of the time. as close as yours is It may be off but it may be better that it is off so you have a few choices.

1. Center it up after setting TDC on the horizontal. (back to factory standard).

2. Leave it alone as you will do no harm where it is.

3. Buy a degree wheel and learn how to degree cams. Beware you will likely find all cams are off from the factory even when in the factory position.

 

[dadouzzu]

Great videos. I don't have the feel needed to set the belt "by feel" so i had to use 110Hz as per last ducati service bulletin (i hope..).
Tools tools tools.....The leak down tester is already in my wish list and probably its also time to add crank rotating tool, degree wheel, piston stop, some kind of dial gauge holder and cam bolt wrench. A lot of tools.....

(My original plan was to do only valve clearance and belt change, so i rotated the crank with the clutch by hand (that was good because i don't have to go to the other side of the bike to do it )

@ducvet

The safest option is the 2, and eventually after the end of covid-19 lock-down i can try to find all tools above for the opt 3.

In the opt 1 how i can set the TDC without the degree wheel?
The factory standard seems to be slightly advanced from where it is now....
If i've done the math good every mm of error on pulley lock groove is 5° @ crank

Thanks

Edit: the vertical cylinder has more "error" than orizontal

 

[ducvet]

You can buy aftermarket tools to lock the crank in place know that it also is about being close enough. Do not expect it to be true TDC which you will only find with a degree wheel.

 

[dadouzzu]

You can buy aftermarket tools to lock the crank in place know that it also is about being close enough. Do not expect it to be true TDC which you will only find with a degree wheel.

Ok, i will look for cost and avaliability.
Maybe if i have to wait and buy a tool is better to buy the correct tool (degree wheel)

 

[ducvet]

For routine maintenance belt timing is all that's needed there is little need to degree or go to that extreme.
Differentiate cam timing from belt maintenance timing.

I do these on a very regular basis and yes I am very familiar with them (which your average owner is not) but see no need to go beyond . I do not lock crankshafts at tune or belt changes as I know where things are and should be. If you are not familiar it buys you safety to buy and use these tools.

 

[dadouzzu]

The 900ie pulley are marked very well.
I think there is no need to lock pulley or crank or mark the belt for a simple belt swap.
It is needed to set the adjustable pulley.
The 900ie service manual is the only one i've seen that recomand to set it every belt swap.
For belt maintenance timing you mean that you set the pulley each time you replace the belt according to the manual?

 

[belter]

eric is saying that you don't need to do any of that when replacing belts. line up the marks, replace belts. that is all i ever do at belt replacement also.

ignore the manual.

if you want to do anything more, get a degree wheel and tools to check valve lift and do a proper cam timing set up.

 

[spacey]

I was a bit concerned about my skills the first time I did the belts on my '92 900SS. I found the following: There are many excellent videos on YouTube on how to do this. I followed the instructions given by Chris at California Cycle Works YouTube channel. With the plugs removed and the bike on a rear stand, rotating the rear wheel in a higher gear is effective for rotating the engine. Placing a dowel or bar in the spark plug hole works to determine when the piston is at TDC, you can look in the plug hole to see valve actuation and position. Don't trap or break the dowel, damage the piston crown or the valves.

Check and verify all timing marks prior to removing the belts. While not strictly necessary, I purchased a tool on Ebay from "Thomasperformanceprarts" that held the cam pulley that is under spring tension prior to removing the belts. My recollection is it was less than $10 US. My bike had the removable lips on the outside of the pulleys that made placing the new belts on very difficult. At the recommendation of Chris at CA Cycle Works, I removed the clips as "unnecessary". I used the 5mm-6mm allen key method to tension the belts. A 5mm allen key should fit between the idler and belt, and a 6mm shouldn't. Using this method I got the belts a little too tight so had to adjust. When back together rotate the engine very slowly to ensure nothing hits. Hope this helps.

 

[belter]

shows the "feel". it's not really feel, it's fairly clear if you play with it.

 

[dadouzzu]

Thank you Brad, next time i remove belt covers i will try to play with it

A lot of experienced guitarists can retune the guitar in the middle of a song, or change tuning on the fly between two song.
I have to use guitar tuner all the time .

Maybe it's better that after playng with it i double check with tuner.
Have you ever measured the frequency on a 900ie (different tensioner) after setting it by feel?

Davide

 

[belter]

the 900 spec was higher than 110 - maybe 140 and 120 - and the feel method usually sees it somewhere in that range from memory.

 

[dadouzzu]

Waiting for rotating tool, let's share the first tool done in case anyone is interested : piston stop
A lot of work for a medieval result, but i haven't found it on ebay...

Tomorrow i will check if it's good, hope it's strong enough and don't hit the exaust valve..

Next on the list: dial gauge base

I can't find the tightening torque for the 3 pulley allen screws. 10Nm or less?

Thanks

 

[belter]

should be m5, so 8nm

 

[dadouzzu]

Ok, medieval and stonage? tools 2 and 3, waiting for proper turning tool to arrive...

With belt as is, 95hz the angles are 22° and 76° (+/- 1°) , centerline at 117° (Averaged 5 measures)

For the vertical cylinder it is possible to measure the exaust instead of intake timings? Is accurate enough?
The belts should be set at 140hz or by feel for the measure?

Thank you

P.s. i've tryed spectroid app, is about the same of ntrack tuner but pickups way better, one pluck one frequency.

 

[StraDuc]

Not sure what engine you are referring to but the 140 Hz spec in the workshop manuals for the DS engined Paul Smart was, I believe, found to be too tight and toasted bearings so was revised down to 100-110 Hz. I have always set the belts on my DS engine at 100 Hz with no issues. I'm sure Belter or DucVet will know for sure but I suggest you research the 140 Hz spec before you set your tension there.