While having the heads of the bike i thought it's a good idea to adjust the valve (and replace the stem seals) I watch some videos on YouTube and read couple of articles i found online. i think i understand the process but hopefully some can confirm that this is indeed the way to go. 1. make sure both valves are closed - on the horizontal head this is when the mark on the pulley is aligned with the mark on the cover. 2. measure the gap between the upper shim and the closing rocker - this seem to be within spec of .010mm 3. press down the closer rocker and measure the gap again, this reading minus the opener gap is the closing gap. this is when i ran into an issue, no matter how hard i press down the closing rocker doesn't move, and the shim itself isn't even turning (i did tried to turn the pully a bit to see if makes a different, but it doesn't) to my understanding this indicates the the gap is to small, from reading around i see the this gap should be 0.002mm to 0, in many places it's says that's its ok to have "no gap" as long as the shim can turn freely in it's place. So are my assumptions correct?, i either need to replace the closing shim to one slightly thinner or grind this shim a bit on a flat surface. On the pantha engine, i need to remove the upper rocker shaft and the rocker to replace the closing shim, do i also need to remove the lower rocker shaft?
To fit new valve seals, you are going to have to remove the bottom lifter so a moot point! The best way (in my humble opinion) to do this is pull the pin, remove the closing spring and do the closing shim with a freely moving rocker. On the 860s, with the closing cam closed, I set my shim so that I can easily turn the shim on the valve but there is zero clearance. Emery paper was used for very careful removal of shim thickness followed by polishing. Do exactly what you did; turn the cam shaft slightly in each direction while closed to see if there are any tight spots on the closing cam then set the shim at the tightest spot. When it's all put back together, just push down on the closing rocker with one finger and make sure the shim still turns easily on the valve stem. I used four little plastic bags and some painters tape to keep all the parts and shims, valve and shaft, in the correct order. Some of the pin shims are really thin and stick to the inside of the head when pin-pulling so be very wary not to lose track of them.
Hi Eran: Let's go back to basics. I pulled the heads off my old 81 MHR, in the warmth of my living room with good tunes playing and a beer on the table. I put the bike away clean 29 years earlier so felt that I owed it a good barrel/head/valve check-over. Pistons/barrels really great, mild carbon deposits on the piston heads, combustion chamber and valves. To do the job right, the valves had to come out to inspect the seats and valve play and replace the seals. With heads on the table I first measured and recorded all the opening and closing gaps; not too bad, a few tight openers one odd, inconsistent closer. Using my new, EBay desmo head tool kit, I pulled pins, rockers, rocker shims and valves shims, storing everything carefully in dedicated snack bags and got to work cleaning the heads and valves; all good, nothing scary. I measured all the opening and closing shims, stuck them on a piece of painters tape, marked-up with dimension and position. I also bought the closing shim measuring tool. What I expected to see is that with clean valves and valve seats, the valves will seat a little deeper so the stems will stick out further so closing gaps will tighten and opening gaps will loosen. After all was clean, on my bike, I had to install the internal valve guide O rings (horrible job), on your bike you only have the top seals. For each valve, I refitted the rockers with pins but no pin shims or springs and then the valve and the original closing and opening shims. I then measured to see the impact of cleaning the valves and valve seats; as expected there were changes so I wrote them down and repeated for the other valves. Remember the inconsistent closer? the fork of the closing rocker had cut a tiny amount of metal away from the base of the shim so that it "locked" into the fork. When I pushed against the spring I could just turn the shim but its movement was not smooth. I would not have noticed this problem if I had not disassembled. I calculated all the "new" shim dimensions required to attain 0.08mm inlet opener, 0.12mm exhaust opener and 0.00mm closers. With what I had to start with, I only had to buy one new closing shim. I was able to reuse as-is or reuse ground-a-little all the other shims. As explained earlier, grinding was done with a fine emery cloth on a flat surface, very slowly, remeasuring often. I only had to grind three shims. I used Solvol Autosol to polish the shim surfaces afterwards. I rebuilt the heads again with no springs or pin shims just to check my work. As described earlier, tweak the cam shafts a little each side of TDC/valves closed to watch out for high spots, especially on the closers. All was good so I then reassembled with the pin shims and closing springs and cam shaft end bearing blocks and rechecked; all was still good. Job done; time for another beer. A really important note, be really careful when putting rocker pins back in; make sure the drilled and tapped hole is facing out or you will be in a world of hurt. Also, some of the pin shims are really thin. When putting them back on, I picked the thickest shims to be in contact with the rockers following Tim Keys' advice from a YouTube video. I really hope this helps. If there are any more questions just ask. I found this job to be a lot of fun. So many owners on forums go on about how this is a trained Ducati mechanic job only. Not true. Just take time, measure frequently, keep things clean and tidy and use the appropriate selection of music and beer.
Some pics for fun: tiny shim, big emery paper: Getting ready to test "new" shims - during actual testing, the pins were pushed all the way in and the camshaft bearing caps were put back on loose:
Rick, Thanks for this very detailed explenation, i think this is the best write up ive seen on this subject! I'm able to pull out the pins with a seld made tool, i dont have the special tool for the spring, and fear it will be very hard to remove it or put it back without the tool. any ideas here? still a bit confused about measuring the closer gap, i always read about measuring the "loaded gap", is there a way to measure this gap with just the closing rocker insatlled (without the thrust washers and spring)
so i measured and took apart the shims on the vertical head, both openers were at 0.20mm so way off, and the closers would not move at all no matter how hard i pose the arm down, so i guess they are on 0.0 or less (binding). i took off the shims on the horizontal head without measuring (i was a bit over enthusiastic ), but from measuring them few days ago the openers were closer to spec at ~0.10mm and the closers were the same as on the vertical head. once I'll get to lapping the valves I'll put everything back together and do all the measuring to determine what shims need attention. is there a way to measure the shims without the special piece?
Hi Eran: It really helps to have the head in your hand and see how it all works. It is my understanding that the loaded gap approach is to help evaluate the closing shims with the heads on the bike; working in tight, awkward spaces. Instead of trying to get the feeler gauge between closing fork and the bottom of the closing shim, at TDC, measure the opening gap and then remeasure the opening gap when pushing down on the closing rocker. If there is closing play, there will be a bigger "opening" gap at TDC. Subtract the bigger from the smaller and you now have the closing gap. With heads on the bench, it's simply easier to make sure that at TDC, the closing shim can be freely turned on the valve stem but only just; your thinnest feeler gauge can't fit between a closer fork and the bottom of the closing shim. If you were unable to turn your closing shims at TDC then they are too tight. When you clean up everything and lap the valves, this will change and they will be looser. If you are lucky, this may be enough to allow reuse of the closers in the same positions. The openers will get tighter! Measuring shims: The little tool ($18) for closing shim measurement also works for opening shims. Any short, 8mm diameter rod can be used as a tool (with some simple math) for opening shim evaluation. The closing shims are trickier without the tool. You could simply fit the closing shims and find the ones that work best for each valve by trial and error and hope you find a combination that works. If you find that you need to order a new one then you may have a problem as you will not know which size to order. Lets say you get three OK and one is too tight; easy, just carefully grind it to fit. If it's too loose you have a problem; you will not know what size to order. Spring tool: I never had to try putting a spring back on without the tool. My bet would be that this would be very tricky. I think the whole kit was CAN$80 on EBay. https://www.ebay.ca/itm/DUCATI-Beve...173981?hash=item46a264029d:g:FzMAAMXQOT5Q9hFS Bearing cap on: I forgot to mention that when checking my shims, I put the end camshaft bearing cap on loosely just in case there was any lateral movement of the camshaft without the end bearing holding the thing secure. Good luck!
i ordered this tool set today, i hate doing a job without the proper tools (the down side is that ill have to wait until it gets here) so your saying that if the heads are on the bench anyway, it's better to measure the closer gap between the fork and the shim and not using the "loaded gap" method.
so today i lapped the valves and started assembly and adjustment, first i did the vertical head inlet, it went ok, had to sound down both closer and opener shims a little but now i can turn the closer shim with my hand but it's not "freely turning" is that ok? the opener is set to 0.010 mm. on the exhaust valve i run into an issue with the rocker pin thrust washers, i cant get them aligned on the "far" side so every time i try to insert the pin it gets stuck, i don't want to apply to much force to not bend a washer. even without washers it's a lot harder to slide in the pin on the far end, it looks like it get jammed. can i lightly sand the hole? on the inlet valve the pin slides in easily so there were no issues aligning the washers.
The closing shim should be able to be turned easily but with no measurable gap. When the whole thing is reassembled with the return spring, you may not be able to turn it without pushing down on the closing rocker with a finger. I should note that there are some YouTube videos showing people using a big screwdriver or similar to push down the closing rockers while making shim adjustments. I found that I was able to do this with my left finger or thumb; it's not "easy" but it's do-able and far better than pushing down on a tool that may slip off. The rocker pin issue: I'm sure you have done this, try the pin alone, nothing else and make sure you don't have oil on the end of the pin and in the closed-end pin hole. The fit of the pin into the closed ended hole is really tight; too much oil and you will make an air bubble inside the hole. I found this out with one of my pins; I could push it in but not all the way and it would pop back out by itself due to the bubble. You should not need to modify the hole to make the pin fit. Try rotating the pin as you push. Alignment of the pin with the shim washers and springs is a PITA. The special tool kit includes a tapered pin which is used to align everything first. You then hold your breath, pull out the pin tool and carefully push in the real pin, turning it as you push. You may need to gently coax a shim or two with a small screwdriver. For obvious reasons, much more tricky with the bottom pins due to the springs and holding onto the spring tool; only two hands..... You can see why this is so much easier with the heads on a table.
even without the rocker and washers, just the pin itself it gets really hard to push it into the closed end hole, i need to use a plastic mallet to get it in, and i need to hit it hard. on the inlet side it went much easier. still had some resistance but i was able to just tap it lightly to go in. strange...
There may be something contaminating the hole. Try cleaning it out with a rag and some solvent, clean everything, including the pin and try again. The four pins are identical (or should be!). You could try swapping pins around to see if one fits a little easier. You should not need to use a mallet. All mine fit by pushing and turning at the same time by hand.
Interesting how many Israelis are playing with old Ducatis this year. On Facebook, I've been communicating with one relatively new bevel 900 owner and one guy looking for one. You guys should start a club!
one of my friends is working on a darmah, another one is bringing back to life his old Indiana. my pantha has been seating at someone's garage for at least 10 years before i got it.
If you are on FaceBook, you should look up Tal Rashevsky and Shon Ko. Shon has a bike workshop and is rebuilding an old 900.
Well after a lot of work, mainly sanding shims, checking and re-checking. the job is finally done and the heads are back on the engine after good carbon cleaning, valve lapping, new seals, gaskets and o-rings. next step, get the pickups aligned, fix their insulation, close the side cover, new belts and hopefully the engine can be united with bike after many many years. @Rick Ducati , thanks for all the great advice!
