Replacing self aligning bearings.

[Haggis]

Hi.

I am new to the forum. My name is Chris and I live in Highland Scotland. What a great site. I have looked at the threads and already answered some of my questions.

For info, my first bike was a 160 and I have had Ducati singles ever since. I also have two Guzzis and an 851, so can find my way around a set of spanners. I have two singles, a Daytona and a NC Spanish. both 250s, both needing extensive restoration. The Daytona came stripped down in several boxes from a guy who took it in part exchange for a French polishing job. He took one look at the bevels and decided it was not for him. - His loss, my gain.

Sadly, the head from the Daytona was left over winter in a plastic box and I did not realise there was a leak in the garage roof. The box filled with water and the head is a rusty mess.

I have stripped the head down but need to remove the self aligning bearing. The (rusty) balls and cage fell out when removed the top bevel gears , but the outer casing is still in. Looking at the exploded view of the engine it appears that there is a "distance piece"(part 97) and thrust washer (part 86) in the head. I presume that these are removed by heating the head and pressing them down, but the exploded view is not very clear. Any advice on removing them would be appreciated. (Associated advice with removing the bottom SA bearing would also be appreciated).

I intend to do a complete rebuild with new bearings throughout and have sourced all of the bearings. The big end appears to be tight, but I will probably have it pressed and inspected just to make sure.

Thanks

Chris.

[DewCatTea-Bob]

" I am new to the forum. My name is Chris and I live in Highland Scotland. "

____ WELCOME to our list of forum-users Chris !



" I have two singles, a Daytona and a NC Spanish. both 250s,

____ It would be nice to see what you have there. _ Do you have any pix to show ?



" the head from the Daytona was left over winter in a plastic box
The box filled with water and the head is a rusty mess.
I have stripped the head down but need to remove the self aligning bearing.
but the outer casing is still in.
I presume that these are removed by heating the head and pressing them down, Any advice on removing them would be appreciated. "

____ Of-course that's not a common-issue, so if you could post a pic or two of exactly what you're having to particularly deal with, then perhaps someone here could then more likely offer you some specific advice (for coping with whatever severity of difficulty you have there).


Hopeful-Cheers,
-Bob

[double diamond]

The bevel shaft self aligning bearing in the head is pressed into a steel collar that is itself pressed into the head. This collar is shown in the parts book in the cylinder head illustration, not with the bevel shaft. To remove, the aluminum bevel shaft tube must be removed by removing the two allen screws to the front and rear of the bearing inside the upper bevel chamber. After you remove the bevel tube, scrape off the gasket that seals the head/bevel tube joint. You may then tap the bevel shaft downward and remove the bevel shaft/bearing assembly. The collar might stay in the head or might come out with the bevel shaft depending upon how rusted together everything is. If the collar stays in the head, heat the head and press it out.

The factory procedure for removing the lower bevel cartridge involves use of a special puller that threads into the flange on the top of the bearing housing. If you have access to one of these pullers, it’s a simple matter of removing the aluminum flange that holds the bevel cartridge in place, scrape the gasket off, remove the bearing shim, remove the circlip and shims from the lower bevel shaft and withdraw the bearing cartridge with the puller. If you don’t have access to this puller, you must split the cases, remove the crankshaft, remove the parts described above and withdraw the lower bevel gear from the bearing cartridge. If the cases and cartridge are not corroded, sometimes the cartridge will simply slide out of the cases with nothing more than pushing it upward with your thumbs. If the cartridge won’t budge, then, using a C-clamp of appropriate size, press the cartridge out by employing appropriately sized spacers. The cartridge is pushed up with a spacer slightly smaller than the ID of the cartridge bore and pressed into a spacer that has an ID slightly larger than the upper flange of the cartridge. Heating the cases will ease removal.

It’s a good idea to at least remove the welch plugs from the crankpin and make sure there are no contaminants accumulated inside the big end pin. Also, of course, remove the threaded plug on the right side flywheel and clean out the centrifugal oil filter. Pressing the crank apart is even better. I’ve disassembled a number of cranks where the rod felt good but the big end bearing was rusted. Matt

[Haggis]

Thanks Bob and Matt.

I am trying to familiarise myself with the workings of the message board, so please forgive my clumsy replies until I work out how to do things.

I will post some pix as soon as I work out how to. They will make grown men weep though.

I have stripped the head down to bare (except the rocker pins are stuck in and I don't want to break the puller thread trying to pull them, so I will heat the head at the weekend and see if that helps).

I have soaked the head in cleaning fluid, removed some of the rust from around the remains of the SA bearing and can now see how it may be dismantled. Previous to cleaning it was a brown furry mess and I could not see the lines between the bearing and the carrier. ( The head is so corroded that I managed to undo the left hand thread on the cam without using a cam holder!).

Mat. Thanks for a full reply. I will work through your instructions and see how far I can get. My plan is to see what I can do with the kit I have, and to ask an engineering shop to do anything I do not have the tools for. Things are hopefully less likely to go wrong if I can give an engineering shop precise instructions. I still have some Ducati tools (pullers and timing pointer) from my youth, but not a full set. I have been guilty of poor practice in the past and have learned my lesson.

Thanks again for the replies. I am looking forward to being able to use the message board properly in the future, and will post some pix.

Chris.

[Haggis]

[attachment=0]SA3.jpg[/attachment=0]

As suggested by Bob, photos attached. Although all of the ferrous bits are probably junk the rest is recoverable.

The photos give an idea of the problems I have.The arrow shows the SA bearing ( minus cage and balls) I was not sure which way it presses out or whether I should remove the sleeve as well as the bearing case. Thanks Mat it is much clearer now.

Much of the rust comes from other metal parts that rusted in the plastic bin. Fortunately the rust is mainly superficial and comes off with a bit of wire wool. I am going to blast the head at the weekend and start planning the rebuild. I have just got some "new" crank cases for the Daytona. The old ones have a broken web inside near the kick start mechanism. It seemed easier to track down replacements than to have the cases built up and forever worry about the repair failing.

I will try to get some photos of the bikes uploaded soon.

Chris.

[Bevel bob]

The steel bushing/cartridge with the lower bevel bearings can be removed and replaced in the cases without any special tools(on my 250!) by just tapping it up from beneath the gear with a drift then lever out , After the circlips removed. It can be done without splitting the cases while the motor is in the frame ,fiddly and not necessary in your case, but usefull to know.Try not to mix up the shims, although they will all need checking, a base line setting is better than starting from scratch.(as I have painfully discovered!).

[Haggis]

Thanks for that.

I have spent the day working on this. The engine is going to get a complete nut and bolt rebuild so everything will be coming out and new bearings and bushes will be going in. I will keep the shims in order as baseline measurements. This will give me a good starting point when it comes to putting it all back together.

Matt. Thanks for the suggestion about removing the welch plugs. I thought that was a great idea until I looked at the crank today. There do not appear to be any welch plugs. Also the crank plug did not want to move even after a couple of dunts with an impact driver. I don't want to screw the slot up - any ideas. The edge of the plug has been punched. I was wondering about drilling the punch mark. - is this a job for the engineering shop? I will post pictures in a new topic.

I had intended to blast the engine today but the compressor has packed in. I am now compiling a list of parts, and coming up with quite a few questions.

This is a great forum. I have answered some questions just by searching, but there are many more to come. It is a while since I did any serious work on these engines, so I hope that you don't mind me asking more than I can contribute.

Chris.

[double diamond]

Chris,

If there are no welch plugs, you might have a non-original big end pin. I’ve seen a few of these where they’re solid on one end and have a plug of some sort pressed in the other. The original Ducati big end pin will have welch plugs on each end. Perhaps some pics to identify the big end pin? One method to remove is to drill a hole in the center of the plug and use a sheet metal screw on a slide hammer to remove the plug. I expect there are other methods. The threaded plug in the flywheel is usually punched at the threads. You can drill the punch with a small bit, helps it come out a bit easier. I use a slotted screw bit that fits tightly in the slot and large ratchet or breaker bar for leverage. Clamp the crankshaft in a vise, push down on the bit to keep it from slipping out of the slot while you turn the ratchet handle. If you have a properly fitting tool and sufficient leverage, the plug comes out easily. In cases where they are impossible to remove, the material of the plug is actually quite soft and can be machined out or perhaps removed with a tool for removing broken bolts (known as an “easy-out” here in the states). As Bevel Bob noted, the lower bevel bearing cartridge will slide out with out much effort in a clean, well oiled engine. I’ve had some where the cartridge slid out with no more effort than pushing it up. But if the engine has been sitting suffering from corrosion, they usually demand more effort. Also, the cartridge housing is pretty soft material. If you use a punch to drive it out, you might damage it. Sometimes a hardwood drift is sufficient but the spacers and C-clamp method I’ve described has been the most satisfying method for me and won’t damage any parts. Matt. p.s. keep those questions coming; wouldn’t want to have you ruining serviceable parts that could otherwise be avoided with a little advice .

[Haggis]

Thanks double diamond. I will start a new thread around the crank. I suspect it will generate a bit of debate. Also, thanks for the encouragement about asking questions. In my youth Ducati singles were my only form of transport, and I became quite an expert in bodging them to keep them running. Bodging is a Scottish word for improvising repairs, but I suspect that butchering them is a more apt description of some of the techniques I used back then. Those bikes have long since been sold and someone somewhere is cursing me as much as I am going to be cursing the owner of this one!! So it is great to have a forum that encourages questions on best practice.

I was worried about ruining the slot in the sludge plug, so the crank has been delivered to an engineering shop today. - I decided that it is better to ask them to remove it than to ask them to sort out the mess I might make. The crank is coming apart for inspection anyway, so it is not much extra work for them. I actually bought some easy outs today, but that was to remove the broken bolt from the rocker arm spindle. ( I presume a failed improvised rocker arm spindle extractor). At least I can pass your advice on to the engineering shop if they do not manage to remove the sludge trap plug.

I have attached a photo of the welch plug. There is more to this baby than meets the eye. The 5 or 6 mm rod in the middle appears to be threaded. As for the rest, it is anyone's guess. The engineering shop are going to start by trying to remove the threaded centre and see what is inside after that. As I said above, I am going to start a new topic because this is moving a bit away from the SA bearing.

Thanks for the info on the bottom SA. I have not taken the cases apart yet. - I have enough horrors in the bits that I can inspect. (The crank was out of the cases when I bought the bike).

Regards

Chris.