M900 recommission

West Cork Paul

Man in a Shed
Subscriber
I thought I may as well start a thread for this one. This bike is an early M900, registered in 1994 but built in 1993 as evidenced by the yellow swing arm strut and the fact the VIN is no.499 off the production line.

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Sadly however the bike has languished unused in a less than perfect environment for the last 10 years and now is suffering badly from surface corrosion pretty much everywhere 🙁.

It’s present owner bought it about 2 years ago from the estate of a deceased biker with a small collection of bikes, the original owner hadn’t ridden it for years due to age and frailty. The present owner intended to do it up but has never got round to it and thus it came to me to do the work.

Sadly, as it was loaded into the van and the owner saw it from a different angle he noticed there was something awry with the front left cylinder head stud.

This is what it should look like
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but if you pull it up with your fingers it looks like this
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Yep, it’s sheared off in the barrel 😕. There’s also an oil leak that appears to be coming from the rear left vertical cylinder bolt 😕.
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So, not only do I have to recommission it and sort out the corroded parts but I now have to completely strip down the top half of both cylinders, extract all 8 head studs and replace them with new ones that aren’t so fragile. You and I both now how this is going to end up for I hate seized parts. Mind you I do have s fair amount if prior experience now 👍.
 
BTW, I have questioned if it’s actually worth restoring as there’s so much needs doing, especially since the head stud issue came to light. By rights the engine should be dropped out of the frame and the frame sent away to be blasted and repainted, then the engine completely split into its components and them all blasted and ceracoated, and the wheels, and the suspension, and so on and so on etc etc. But, he wants it done just maybe not, for this year, as extensively as the cosmetics should be, I’m to focus on the engine and running parts for now.
 
I thought I may as well start a thread for this one. This bike is an early M900, registered in 1994 but built in 1993 as evidenced by the yellow swing arm strut and the fact the VIN is no.499 off the production line.

View attachment 75446
View attachment 75447

Sadly however the bike has languished unused in a less than perfect environment for the last 10 years and now is suffering badly from surface corrosion pretty much everywhere 🙁.

It’s present owner bought it about 2 years ago from the estate of a deceased biker with a small collection of bikes, the original owner hadn’t ridden it for years due to age and frailty. The present owner intended to do it up but has never got round to it and thus it came to me to do the work.

Sadly, as it was loaded into the van and the owner saw it from a different angle he noticed there was something awry with the front left cylinder head stud.

This is what it should look like
View attachment 75448

but if you pull it up with your fingers it looks like this
View attachment 75449
Yep, it’s sheared off in the barrel 😕. There’s also an oil leak that appears to be coming from the rear left vertical cylinder bolt 😕.
View attachment 75450

So, not only do I have to recommission it and sort out the corroded parts but I now have to completely strip down the top half of both cylinders, extract all 8 head studs and replace them with new ones that aren’t so fragile. You and I both now how this is going to end up for I hate seized parts. Mind you I do have s fair amount if prior experience now 👍.
That oil leak doesn't look to bad but good luck with the bolts, you will have too let us know how many break off :).
 
Maybe I should start a poll 🤣.

Ducati changed them from engine number 014364 on, this one’s 11646 😕 so, yes, all 8 have to be done.
Fuck that, i hate anything cylinder head bolts and my nemisis the exhaust stud, broken a fair amount of them fuckers. I had a GS550 that i made into a streetfighter, i made a single seat unit and it had a GS1000 rear wheel and a Harris 4 into one pipe, i had to remove said pipe and broke six of them!!:eek: I had to buy a helicoil kit, that was fun!!:rolleyes::)
Start a poll dude.
 
Head removal time 👍
There’s been daily applications of penetrating oil on the head studs/nuts and all 8 nuts are loosened off and can be undone, which is a good start. But before I do, and in order I can undo them fully and lift the head, I need to remove the cam pulleys.

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The nuts came off ok but the pulleys themselves don’t. On this engine (93) the pulleys appear to be an interference fit and judging by the two threaded holes, at 1 o’clock and 7 o’clock in the photo above, it appears it’s necessary to attach an extractor tool, similar to the one used to pull off the flywheel crankcase cover. But… does anyone know what thread size those holes are? M6 is too big, M5 is too small and I’ve never heard of M5.5 and certainly can’t find an M5.5 at the nut/bolt/fixings suppliers 😕
 
Head removal time 👍
There’s been daily applications of penetrating oil on the head studs/nuts and all 8 nuts are loosened off and can be undone, which is a good start. But before I do, and in order I can undo them fully and lift the head, I need to remove the cam pulleys.

View attachment 76112
View attachment 76113

The nuts came off ok but the pulleys themselves don’t. On this engine (93) the pulleys appear to be an interference fit and judging by the two threaded holes, at 1 o’clock and 7 o’clock in the photo above, it appears it’s necessary to attach an extractor tool, similar to the one used to pull off the flywheel crankcase cover. But… does anyone know what thread size those holes are? M6 is too big, M5 is too small and I’ve never heard of M5.5 and certainly can’t find an M5.5 at the nut/bolt/fixings suppliers 😕
When the fucking Italians use M15 rear sprocket nuts i would say M5.5. :unsure:
 
Head removal time 👍
There’s been daily applications of penetrating oil on the head studs/nuts and all 8 nuts are loosened off and can be undone, which is a good start. But before I do, and in order I can undo them fully and lift the head, I need to remove the cam pulleys.

View attachment 76112
View attachment 76113

The nuts came off ok but the pulleys themselves don’t. On this engine (93) the pulleys appear to be an interference fit and judging by the two threaded holes, at 1 o’clock and 7 o’clock in the photo above, it appears it’s necessary to attach an extractor tool, similar to the one used to pull off the flywheel crankcase cover. But… does anyone know what thread size those holes are? M6 is too big, M5 is too small and I’ve never heard of M5.5 and certainly can’t find an M5.5 at the nut/bolt/fixings suppliers 😕

Could be No 12?

 
Paul, hope this may be of some help, years ago I helped a mate who had a early ninety's 900ss, it needed the seals replacing behind the pulley, in the plastic cover?
Its been a while and my memory isn't what it was, but we knocked something similar up to this.
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The only other thing we thought about was making an improvised slide hammer!
 
Can you see if there is a snap ring stopping removal?
No snap ring or circlip there
That’s the jobby 👍 but at £151 no thank you.
Paul, hope this may be of some help, years ago I helped a mate who had a early ninety's 900ss, it needed the seals replacing behind the pulley, in the plastic cover?
Its been a while and my memory isn't what it was, but we knocked something similar up to this.
View attachment 76114

The only other thing we thought about was making an improvised slide hammer!
That’s exactly it, it’s just finding the correct size thread.
Drill the holes 6.75mm and tap to M8? Then make up your own puller plate
Good idea. I may have to go down that route.

However, bizarre as it sounds it has occurred to me it may be an imperial tap 🤔. I was looking at tools to remove such offending items and one comes with a load of metric threads but also some imperial adapters 🤔.
 
No snap ring or circlip there

That’s the jobby 👍 but at £151 no thank you.

That’s exactly it, it’s just finding the correct size thread.

Good idea. I may have to go down that route.

However, bizarre as it sounds it has occurred to me it may be an imperial tap 🤔. I was looking at tools to remove such offending items and one comes with a load of metric threads but also some imperial adapters 🤔.
Fucking Italians dude!! :ROFLMAO:
 
How time flys.
I ordered the BGS puller @Noobie referenced above, as it’s 1/2 the price of the one from Ducati just after that post (it’s probably BGS in Germany who make the Ducati one🤔). However you can’t buy it direct from BGS unless you go into one of their retail outlets in/around Berlin so I had to order it through Stein-Diense. Only problem is it wasn’t in stock and was on back order with BGS 🙁. Some 6 weeks later it finally arrives.

I also ordered new cylinder studs from @Exige - thank you.
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Cam pulleys finally removed I could attack the cylinder head nuts. Whilst waiting for the cam pulley remover tool I’d been applying penetrating oil on a frequent basis and, fortunately, all 8 of them came undone without too much of a struggle 👍.

Vertical head off
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Now to attack the studs. First with the double nut trick.
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Well, bugger me, after a bit of penetrating oil application and some force it starts to turn and before long the first is out.
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Followed, over the next hour by the other 3 of the vertical cylinder. It took an hour or so because although they turn they don’t come all the way out, they have to be turned back in then turned out until stiff resistance is felt then penetrating oil applied then turned back in and out a bit further and so on. Patience is key. Eventually 4 new ones are in👍
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The observant amongst you will notice I didn’t remove the vertical barrel but removed the stud and replaced it with a new one. I didn’t want to have to disconnect the piston from the conrod but more on that further down.

Just FYI the original studs are 7.5mm in diameter the new ones 9.3mm, almost 1/3rd thicker, and high tensile steel from APE.
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Moving onto the horizontal, I had to remove the barrel on this one because otherwise I’d never be able to get access to the broken stud.

Hard as I tried to keep the piston in the barrel when removing the conrod pin I couldn’t, the bottom oil scraper ring is less than 1mm above the clearance cut out for the pin and it popped out 🙁.
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Now I’ve had to order a piston ring compressor 😕 so I can reinsert the piston & rings.

On to the stud removal.
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The first 2 came out relatively easy albeit slowly for the reasons set out above.
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But the top right gave me a lot of grief, firmly stuck - and I was feeling so pleased with myself too 😕. The jam nut trick didn’t work, they both turned. I fitted a second jam nut, ie 3 nuts, they still all turned in unison up the thread. I fitted some different nuts and got the impact wrench on the top, no good 😕. All the while I was applying heat and penetrating oil, then leaving it for 30mins then more heat then twisting. Eventually, when I was getting really frustrated and thought wtf am I going to do - all the while I’ve been thinking ‘don’t snap on me’ too - I gave it one very long heat cycle, the crankcase around the stud thread was beginning to get red - this time it turned the tiniest of amounts - hooray 🙏. It still took 45 mins of in/out to eventually get it out mind you, it was well and truly jammed in there.

That one was so bad I was dreading doing the broken stud as there was nothing to get purchase on, the stud extractor just slipped around it. Then I had the brainwave of using the die grinder (thank you @WAYNE ) to grind some flat edges on the stud so the extractor could get a grip. It worked and, thankfully, the broken one came right out 👍
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When the studs came out I noticed there was s lot of slough (sluff?) aka crap on their threads, metal filings, so I thought I’d better chase out the thread with a tap. Feck me, it’s no wonder they were tight to undo (that’s grease on the tap to collect and hold the slough)
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It’s as though when the threads were tapped in the factory they didn’t clean out the holes. Having done the 4 on the horizontal cylinder the new studs could be twisted all the way home just with my fingers. That wasn’t the case on the vertical cylinder. Now I’ve a piston ring compressor on the way I’m going to pop off the vertical barrel, remove the new studs, clean out the threads and refit the studs.

A bit of a clean up of the piston crown and head/valve faces during my ‘waiting for penetrating oil’ moments,
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and a debate as to whether I had enough tools out for the job 🤣
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Trust me that’s just the 1/2 of it there are more out of view on the other side of the bike.

One question - having never lifted the heads off the barrels on this bike before - are there no head gaskets? I ordered a cylinder gasket kit from Ducati but it doesn’t contain any, just base gaskets, o-rings, valve cover & inlet manifold gaskets, and, I see none on a parts diagram. There is a recess in the head and a lip on the barrel that seats in the head recess but it’s just 2 bare metal faces against each other. I ask, because on one of the heads there’s evidence of exhaust blow through between the head and barrel, I cleaned off some baked on carbon outside the barrel/head interface.
 
We love threads like this, it's always great to see how others overcome little problems that our bikes throw at us ! ;)
I'm no expert on these engines, but I'm sure I've seen/read somewhere about certain engines not having a head gasket, relying on the stepped lip to make the seal. Someone will know for certain though.
 
The best thing to use for cleaning out threads are "thread chasers", they clear the threads or reform slight nicks/burrs in the thread rather than cut more material out, which a tap would do/does.

Where you have "blow-by" is that where the broken stud was or a different position/cylinder ?
 
The best thing to use for cleaning out threads are "thread chasers", they clear the threads or reform slight nicks/burrs in the thread rather than cut more material out, which a tap would do/does.

Where you have "blow-by" is that where the broken stud was or a different position/cylinder ?
It is the horizontal cylinder head, which had the front left stud broken so, yes, it could be as a result of that.
I thought I’d taken a photo before I started cleaning the baked on carbon off but apparently not. This photo is from part way through the cleaning process, you can see the marks (hot gas marks?) in the 12 o’clock position.
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When the bike first came to me, back in April I checked the compression on both cylinders at the request of the owner. They were about 105 to 112.5psi, on a cold engine so a hot engine would be 20-30 more which puts them in line with spec and it was the vertical which was slightly less. But, for sure, it looked like there was some blow by.

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The older Ducatis did not have head gaskets. When you took the heads off, all you had to do was replace the oil gallery o rings.
I used to just pull the heads off my Darmah to do the valve clearances. The bevel drive was awesome for that, no pissing about with timing marks just bang it back on and tighten 4 nuts!
 
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