Ducati 900SS engine work and freshen up.

[Uncle Flash]

Grabbing a handful as I accelerated onto Hepburn Ave this morning surprised me with an explosive pop sound from the front of the bike. Another infamous Ducati peculiarity rears its ugly head.

Actually, this is not as bad as it sounds. Just about everyone who has owned a belt drive will tell you that the head studs are a weak point and they do break often although I’m not sure it’s as common as people think. The best part about a snapped stud is you can bet your last dollar it will break 1mm out from the block. It’s some sort of law of physics.

With my bike, I snapped the two studs either side of the belt. With the other two bolts holding one side down and the belt stopping too much forward movement, damage has been confined to the studs alone. My main worry was that the belt had let go too but everything is holding together nicely.

I had recently decided to give the bike a birthday so I have a full set of shims in the toolbox ready to go and a couple of belts due to arrive in the next few days. Last weekend was supposed to be the birthday but I forgot to order the belts. At least I’ll have some of the parts to fix the bike but I have a feeling this job is starting to get bigger already.

For starters; I’ve read where a broken stud has been replaced individually but I’m all for doing the whole lot. The studs aren’t exactly expensive and a top end gasket kit shouldn’t break the bank so I’ll pull both barrels and heads and see if I can fit those 210 cams I’ve had sitting in my office for ages. Fitting those will need the pistons modified as well but if it’s all coming apart, what better excuse do I have?

I will also have to drop the engine to work on it which means the bodywork, wheels, and frame will be in the right situation to be painted. I can also take the time to have a look at the rear shock. It’s de rigueur to fit an Ohlins shock on Supersports but after rebuilding the forks with Race Tech parts, I’m keen to do the rear too.

Now I’ve made all this sound rather easy but there are a few difficulties waiting for me. Having to make the special tool for the head nuts is one (I’ve promised myself I would do this) and the fact that I really should fit adjustable cam pulleys to make the most of the timing is another. Hopefully, Brook Henry will have knocked up another batch by the time I get to that stage.

So there you go. I have it all ahead of me but I do have plenty of tools and whilst not too bright, I do have access to people who know what they’re talking about. With a bit of luck, this should all be ready for the summer.

[Uncle Flash]

A quick update:

If you want standard parts for this bike they're readily available. The prices are reasonable and just about anyone can get them for you. If you want those parts to be a little bit better than standard, nobody has them on the shelf and you had better be prepared for a long wait. The good news for everyone is that the genuine Ducati gaskets are cheaper than any alternative I could find.

The APE studs should arrive early next month along with the Superlight rear brake parts and some nice new brake levers. Belts, shims, filters, and other maintenance parts are already here and I already have most of the tools required. I got lazy with the 15mm head spanner and bought one. I could have welded a socket to a ring spanner but I'm getting pissed off with waiting around. A Ducati '94-'97 workshop manual is on the way but I doubt it will replace the Haynes manual I have on the shelf. I just had to have one.

Nobody has a set of adjustable cam pulleys except some mob in Germany and the Vee Two items won't be available for months. This means I may not bother fitting the high torque cams and just go with the high compression pistons instead. I believe the gains are about the same for each mod but I think that doing both could push the compression too high, so I tosses the coin...

The panels should have been removed and dropped off to everyone's favourite Potato weeks ago but with the AIS also dead in the carport, I seem to waste too much time fixing other problems. Still, at least I have my AIB for work.

[Screamin TE]

Got some pics of the progress? I for one am always interested in mechanical repair pics!! Good luck with the repair mate.

[jules_1972]

Keep the information rolling, pics would be great.

All of my studs came out of the cam belt side pretty cleanly, the alternator side was grief!!
2 ok, 1 stripped the thread the other cracked the housing...

[Uncle Flash]

I've never done these studs before on a Ducati but I helped on a Suzi 1100 once and we did something similar. Two broken studs with about 1mm showing. Two grown men sitting on the workshop floor, heads in hands. Fortunately, a new bottom end was available at the wrecker. We could have drilled them out but time v cost... Sometimes it's just easier to buy a new one.

Luckily, I have a couple of very experienced blokes in the workshop who can help me with this if it looks nasty.

And I love taking photos. I should have some as soon as I can steal my camera back from my daughter. She's one of those who believes that possession is nine-tenths ownership.

[Screamin TE]

Gentle heating on the ally case, bit of loctite freeze and a hammer and punch might see you out of shot creek if they are broken flush mate!!


Sent from the bone fone....

[Uncle Flash]

Finally! All the parts have arrived. As this might take a few weeks, does anyone have a tip for an engine stand? I was going to knock something up to fit in the lower threaded holes on the cases but I'm concerned I might be missing something obvious and it will get in the way.

Or do I get the lads to weld me up one of these?

!CFHYh5QBWk~$(KGrHqQOKocE0g2pWoWlBNUFK3dVkw~~_12.JPG !CFHYbDg!2k~$(KGrHqMOKiME0oRNg+cIBNUFKqEvGg~~_12.JPG

[Uncle Flash]

As is usual with all motorcycle related projects, think of the worst that can happen because it probably will.

tank 015.jpg

The initial plan was to have the panels painted while the motor is being worked on but before they could be dropped off, rust was found in the fuel tank. It’s not much and rather than just rub it back and bodge it, I chose to fix it properly by using POR-15. There are probably other brands of tank sealers available but this one was available just around the corner and came highly recommended by past users.

So, starting with the tank removed from the bike.

I detached the cap by removing the screws either side of the hinge, the one closest to the forks (the other two are just decoration), and the last one beneath the cap. The lower half of the filler was removed by unscrewing the grubscrews around the inside diameter and detaching the drainage hose. There is a seal around the outside of the filler that should be inspected and replaced if necessary.

tank 007.jpg

The filter and fuel pump came out easily once I had removed the top hose clamp above the filter.

tank 008.jpg

The pump was attached to the fuel level switch with a couple of leads so I marked one to ensure it went back to the correct terminal later.

tank 011.jpg

From there it was easy to remove the switch from beneath the tank and withdraw the leads. The remaining hole was plugged with a plastic cap I found in the workshop. I used the drainage hose to connect the filler drain to the fuel feed line effectively sealing both and used a small length of shrink wrap melted at the end to seal the fuel return line.

tank 022.jpg

Boom? I was careful not to use my blowtorch lighter to heat the shrink wrap inside the tank or anywhere nearby as there were probably still flammable fuel vapours present in the tank. I melted the tube at the end and shrunk the middle so it would slide onto a snug position. It actually worked well but a small rubber or cork stopper would have done the job just as well.

[Uncle Flash]

At this point I added the container of Marine Clean to the tank along with a litre of hot water and a handful of medium sized screws. Some people prefer to use old nuts and washers for this but I like the idea of all those sharp threads scraping the rust away rather than pounding it. Each to his own.

After thirty minutes of regular agitation, the tank was drained and rinsed thoroughly. I should have worn rubber gloves here as I managed to get the nasty mix over the fingers on my left hand as I was unscrewing the drain plug. It is an alkaline substance and quite caustic. By the time I rinsed it the damage had been done. I have less skin on three fingers and very dry skin on the rest of the hand. Much skin repair cream was needed.

Closing the gate after the horse had bolted; I grabbed a pair of gloves for the next step.

The Metal Ready was poured into the tank which wasn’t quite dry but apparently that doesn’t matter. This I sloshed around as best I could to cover the entire interior. This step neutralises the metal after its alkaline wash and prepares the surfaces for coating with sealer. This is also rinsed out with water but the tank needs to be thoroughly dried before the next step.

tank 031.jpg

Drying the inside of a fuel tank isn’t easy as air doesn’t naturally flow through fast enough to evaporate the water. However, I stole my daughter’s hair-dryer which did the job in no time. There was some flash rust over some of the surface but it was expected and using the dryer kept it to a minimum. Most of it rubbed off with a rag.

tank 032.jpg

I had been warned that the final sealer will not stick to anything even remotely damp and that even when you think the tank is dry, it probably won’t be. Way down in the welded seams will be small amounts of water soaked up by the microscopically irregular surface. Hit it with more hot air and even more after the tank has a chance to cool down. I did this but as seen in one of the later photos, I missed something quite obvious.

With the tank dry, I opened the small can of sealer. The instructions are to mix until a uniform colour is reached but after fifteen minutes I realised that it was always going to look like mica paint and it was as good as it was going to get. Pour it in carefully avoiding splashing it anywhere. The word is that the sealer is almost impossible to remove from any surface and even when wiped up, the silvery sheen stays forever. Once on skin, it’s there until the skin wears away. Don’t do this job in Mum’s kitchen!

The sealer is actually quite thin and I had no trouble covering the interior of the tank by rolling it gently. This was something I was concerned with and had a brush ready in case the small amount required spreading but it wasn’t needed. In fact, when I drained the excess at the end, most of the sealer ended up back in the can.

tank 033.jpg

The instructions stated that the sealer will take up to four days to cure enough to be refilled. The sealer doesn’t dry like paint through evaporation but by drawing on moisture in the air for the hardening through chemical reaction. Too much moisture however, can cause problems; the sealer will bubble and leave tiny pock-marks behind when dry. In my case, I must have not been diligent enough drying the area beneath the fuel filter clamp. This is a larger plate that is spot welded to the bottom of the tank and the bubbles can be seen in the following picture. This area will require touching up once everything is cured.

tank 034.jpg

All in all, this is an easy product to use. A hairdryer is an absolute necessity as are rubber gloves but there was no part of the operation that proved difficult or messy. I’m also left considering if the use of this product as a protective coating on a new or non-leaking tank might not be such a bad idea.

[duc13]

Nice work Flash . Have never used POR-15 but have always heard good things about it.

[Uncle Flash]

I'm at a crossroads with this project:

It's taken ages to get the AIS together and running but it needed to be finished before I could start the 900. That's okay as I finally managed to score a couple adjustable cam pulleys on the 'bay. They're not the billet aluminium items but they did cost only 15euro. Quite a few of the later two valves came with adjustables stock and I think mine came from a 620. Either way, they do fit the Vee Two 210 cams I have on my desk. Which I may not end up using...

These engines are fairly basic creatures that tend to be held back by the head design. Even with better carburation and exhaust disposal, the head still needs work to fill and empty efficiently. My abilities as far as porting go only as far as polishing so I'm not going to make any real gains there. I really should use the 210 cams but will the combination of H/C pistons and cams push the compression high enough to create its own set of problems? Because of my need to make this build work reliably from the start, I'm going to leave the cams out for the moment. At least until I can be sure that an aftermarket ignition system will be able to a better job than the one that came with the bike.

Tomorrow the engine will be dropped, the frame stripped for painting, and hopefully I can put together a temporary engine stand.

[Uncle Flash]

It seems the underlying theme of anything I do is if it can go wrong, it will. This time it’s more a case of it could be worse.

I decided the next part of the job would be easier if I did it at work. Fortunately, the boss allows out of hours use of the business premises and as most everything I could possibly need is there, why struggle in the carport at home? Ladies and gentlemen, I present the ten ton overhead bike lifter. Handy for those little jobs around the workshop and how I wish I had something like this at home. Getting the bike into the tray wasn’t anywhere as easy as getting it out, especially in the 38°C heat.



Once the bike is up high enough to have a good look at the engine, the usual suspects appeared:

Seeping from plugs everywhere.



Corroded fasteners.



Rotten rubbers.



Bubbling paint.



I couldn’t work out where this blow-by was coming from but reassembly should fix it.



Exhaust manifold fasteners always look this way after many years on a bike but come apart easily with a squirt of CRC.



I could never understand why Ducati didn’t put a nut on the rear engine mounting. A little rust was present in the frame mounts but nothing to worry about.



This one was annoying. The chain had chewed into the top of the swing arm clamp screw and made it impossible to insert an Allen key. Careful use of a small cold chisel opened it back up but the angle was difficult to get onto.



The two kick stand screws. I had to cut a slot in the tops and use an impact driver to get them out. I don’t normally recommend using an impact driver for anything this small but the combination of corrosion and the locking compound had these babies in for the lifetime of the bike.



Washed and sitting comfortably on the temporary stand.



It doesn’t look quite so bad now the gunk is gone but the pressure wash also removed half the paint. No matter, I have plans for a new finish that should be a little harder wearing.

I couldn’t wait to see the broken studs so I quickly stripped off the front belt and lifted the head. My concerns that the studs had broken close to the block were still worrying me and the first look wasn’t helping any. As can be seen, the top stud will have plenty to get hold of but the bottom?



Removal of the barrel showed enough of both studs were available to work on. Maybe this is turning out better that it could have been?



Unless of course, you check the condition of the head after you’ve patted yourself on the back and praised the Lord for ten minutes.



Note the top stud has broken inside the head. This wouldn’t be a problem if the stud could be pulled through but the head design doesn’t allow the nut to be lifted straight off. When fitting the nuts they have to be inserted from the side and then screwed down. There is approximately ten millimetres of movement available which I hope to use by lifting the stud and holding it with pliers. I bet the nut decides to be seized.

[Uncle Flash]

Half the worries are over.

The nuts on the broken studs were only finger tight. The one that had broken off inside the head was held beneath the nut with a pair of long-nosed pliers.



Lifting the vertical barrel came with its own surprise requiring some careful cleaning.



The block minus the barrels. It looks terribly untidy and I’m trying to work out if I should split the cases and do a proper paint job. If the infamous oil galley plug in the crank is unscrewing, I’ll have it apart.



Looking down through the top of the case does not show anything touching the crank bearing. If the oil gallery plug was backing out, it would be visible just above the upper screw in the picture. There is a rumour that this only happens on the very early model years but I’ve read of instances up to 1997 models being affected.



Looking deeper, it looks like 6th gear is missing metal on its teeth. Or at least I think it’s 6th. I’ll have to look into this but as I rarely use top anywhere but on the open road, I’m not concerned too much.



Ye olde way of removing studs. Soaked overnight with penetrant and then slowly leant on until the studs start to move. I was taught to gradually increase torque very slowly and not to go at it too fast. A lot of older thread locking compounds are actually quite liquid if you give them time to move. No need for heat this time but sometimes you have to use it.



Ta-Da! Once I’ve chased out the threads (M10X1.5 I believe) she’ll be ready for the new studs.

[jules_1972]

Excellent work Flash!

6th gear looks like a worry, had the layshaft + gear changed in mine for same reason.
glad ur studs came out without to much grief.

I look forward to the next update!

[JAFA]

Very nice work Flash, and nicely documented with plenty of pics. You should write your own manuals. Keep up the good work

[duc13]

Very nice work Flash, and nicely documented with plenty of pics. You should write your own manuals. Keep up the good work

+1, nice work flash!

[Uncle Flash]

Chased out those threads today but didn't get much else done. The two broken studs cam out easily with my trusty stud remover.

While I've got the heads off I'm replacing the valve collets with the spiffy MBP items. They're nicely made but they do add extra height to the closing shims. I'm going to have some fun shuffling the shims around and I just know that when I get to the last one, the closest shim will be 2mm too thick. I did a quick measure of the clearances before I started and surprisingly the closing clearances were quite large. The openers were fine even after 10000km.

And not to forget to replace the valve stem seals at the same time? I almost did.

[Uncle Flash]

I didn't touch the motor today, preferring to strip the frame instead.

With all those wires leading everywhere it looks complicated but was easily done once the cable ties were removed. What is remarkable is the light weight of the steel frame. Stiff and yet surprisingly light for something that looks so industrial.

The frame and cockpit sub frame are now ready to be dropped down to Potato's place once they're blasted. Any recommendations for a business to use?

[470four]

Great thread! I have a '95 900SS of which I will shortly be dropping the motor out for belts, shims & Arias hi-comp pistons... am following this thread with great interest...

[potato]

I didn't touch the motor today, preferring to strip the frame instead.

With all those wires leading everywhere it looks complicated but was easily done once the cable ties were removed. What is remarkable is the light weight of the steel frame. Stiff and yet surprisingly light for something that looks so industrial.

The frame and cockpit sub frame are now ready to be dropped down to Potato's place once they're blasted. Any recommendations for a business to use?

perth powder coaters,soggy wombat on here