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Discussion Starter #1
I am doing the valves on the new to me 1999 900 SS
Good thing too, guy I bought it from said he just did the belts. Both are WAY too lose, 6mm allen goes between the belt and bearing easily, didn't try anything bigger, but it probably would have gone too.

Anyway, valves are a little bit out of Ducati specs. My plan is to use the LT Snyder specs (.004 open, .002 close)
Specs right now are.
Horizontal Intake .002 open, .0025 close
Exh .008 open, .005 Close
Vertical Intake .004 open, .008 Close
Exh 007 Open, .006 Close

My questions are.
Anybody else run as tight a tolerance as Snyder suggests?
I have read about the procedure, and have seen it done with the cam belts on and the cam belts off, any preference? Why?

Belts off makes sense to me as I have also read that after you shim the valves, turn the cam to see if there is any binding, because if you get the closers too tight it will bind the cam as it rotates through.

Thanks in advance for any advice.

P.S. Job is on hold right now waiting for a shim kit to show up.
 

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5,149 Posts
I run the same spec's now as we always did at the dealership I trained at.

Openers .004 intake
.005" exhaust
closer .000
no preload allowed, this is why you need to have the belts off so you can verify that you do NOT have preload on the valves.

I would not shoot for .000 if you are doing it yourself the first time as you might make a mistake and it is easier to shoot for .0005 or .001". Keep in mind the looser the closers the more wear you have in the system. this also means pay attention to the 1/2 rings put them in as they came out, do not flip them or they will break in and loosen about .001" in as little as 500 miles. Same with new 1/2 rings if you put in new they will loosen .001-.002" after running a while.
 

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I've been looking at the half rings ducvet...I use a light, I use my bifocals, I take my glasses off, I squint and curse my aged eyes, I use a hand lens (10x) and...I still can't tell what the heck I'm looking for. Have any tips to tell which half of the ring was up and which was down?
 

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The inside edge of the half-ring will have a shiny spot on one side. That is the top. It can be real tough to see on some of them. It's made by the ring coming in contact with the recess in the valve as it gets pushed up.
 

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Discussion Starter #8
Finished with the valve adjust.
With the weather it will be a time before it is on the road.
Went to the small side of spec on the closers. I seem what was meant by resistance when turning the cam.
Most of the shims I had to lap some. Made it kind of easy to set the closers. Put the shim in, turn the cam, feel resistance, take the shim out, lap another .001", put it back in and turn the cam until I felt no resistance.
Thanks again for the help/

P.S. the description on how to tell which side of the retainers was mostly moot. Only 3 of the retainers in the bike weren't broken.
 

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Discussion Starter #9
Decide I wanted to add one more thing

Doing the valves with the belts off is good for one more reason.

If you put the piston at TDC for the cylinder you are working on, you don't need to used a forcep to hold the valve. The piston will hold the valve up high enough.


Just be sure you are at TDC and remember not to turn the engine on you could be fishing for a valve.
 
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I just did my 796 a few hours ago and I went with the 004 intakes , 005 ish exhausts, and 0005 ish closers.

I tried to get the collet rings on as they came out but, honestly, I was fortunate to get them in at all.

I ended up hand lapping one closing shim and one opening shim

I'll bet if you have this "done" by dealers, your not getting much done at all, I can't see the skill level being up to doing this.
 

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I am hot and cold with getting the collet rings in and out. I pulled my top end apart this winter and had zero issues taking out the shims, measuring them, then putting them back in. I looked at each ring under a magnifier to figure out which way they went, and that was it. However, I had to remove one shim from a valve on the H cylinder in the spring, and man o man it took me forever just to get them back in... by the time they were seated I couldn't care less which way they had gone in. I think next time I'll coat each half ring with a little grease so it sticks to the valve stem. I also had to lap a couple of shims, it's not a big deal.
 
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