Winter Layup - 1995 Ducati 900 Supersport

[pete376403]

Cleaning the cases in the dishwasher brings them up nice.
Also, snap rings - the end faces are not parallel (not the ones I'm used to, anyway) if they are put on backwards and up against something, like a gear, the pliers will always slip off. the pointy bit should face outwards, eg \ / if this is the ends of the snap ring, the wide gap should abut the gear

[OddDuck]

Cleaning the cases in the dishwasher brings them up nice.
Also, snap rings - the end faces are not parallel (not the ones I'm used to, anyway) if they are put on backwards and up against something, like a gear, the pliers will always slip off. the pointy bit should face outwards, eg \ / if this is the ends of the snap ring, the wide gap should abut the gear

Yeah, had a lot of trouble with this. The Ducati ones are square-cut, so as soon as you open them up, they want to pop off the pliers. The fix is to push them onto a textured jaw, past the jaw edge, so that the inside edge of the ring's cut face will bite in and engage.

Thanks Ocean1!

Tonight's short effort (tired from the stint on the weekend) was all about the shift drum fork, the weird hook-mouthed thing that looks a bit like a shark. I spent a while having a play, again. Trying to tidy the shift fork mechanism up didn't resolve the false neutrals.

I think my shifting issues are half and half between technique and wear. The engagement dogs for 5th and 6th are on a slower shaft than 1,2,3 and 4. They take longer to line up and then engage, so riding technique has to be to hold the shifter in for around double the time I'd use for the lower gears. Can't say I was doing that...

Also I think the shift drum fork may have been originally a bit on the wide side, and given some wear it might now be marginal. The problem is that I can't find a specification for end-to-end length in the fork's hook groove anywhere. The Stein Dinse order finally went through tonight, with a new shift drum fork added in. I'll be able to measure a new one against the old and see if there's a significant difference.

Final note for the night concerns Ducati's shift drum plunger stop, the ball bearing on a spring which provides the detents for the shift drum. I think the ball is having trouble rotating on the open end of the spring, there seems to be a lot of friction getting the drum to start moving. It's a pretty basic system and a proper roller plunger could improve things.

An idea to have a play with: a plunger for the spring, brass so it doesn't bind on the aluminium case, and spherically cupped to provide a decent oil lubricated bearing pad for the ball bearing. Shouldn't take long to lathe something up and give it a try.

[OddDuck]

Swingarm bearings.

Ducati use a pair of shell roller bearings, plus an outboard and inboard grease seal, on each half of the crankcase. The seal+bearing+bearing+seal assembly is back-stopped by a snap ring, completely inaccessible if the motor is assembled. This was presumably never intended to come apart.

Problem: sometimes people get frustrated with a swingarm axle that won't go back in, so they drive it in with a mallet. The usual story with a Japanese bike is that the swingarm is on a bushing, both axle and bushing have entry chamfers, a bit of bodging is usually needed anyway and no harm is done. Here it's on thin-shelled bearings. Any load or impact on the end of the bearing shell distorts that shell, locking the inner race. The rollers then start to cut their way into the axle. That's exactly what's happened here, as shown by the damage to the seal cage, the fact that the first roller won't turn, and that my swingarm axle has a shallow cut in the plating.

The seals, aside from anything else, are twenty-plus years old. The outer seal on the other bearing is missing chunks of rubber. It's pretty clear that the seals at least have to be replaced, and while I'm in there it'd be silly to not change the bearings. So: how?

The usual story is that people take an old swingarm axle and simply smash the whole lot up, deliberately pushing the snap ring out of its groove and into the cavity between the crankcase halves. It's gasketed and sealed, so none of this gets inside the engine. Then they smash bearings and seals to bits against the inside of the crankcase and use a mechanic's magnetic retrieval tool to pull the bits out. It's pretty rough but it gets the job done.

With the casings split, I have access from what was the inside. Might try lathing up a specific drift out of some bar stock and seeing how that goes. I managed to get the outer seals off quickly enough by using two flat-bladed screwdrivers, one as a fulcrum so that I wasn't pulling on one seal face but pushing on the other. The gasket surfaces on the casing halves have been masked in preparation for a go at the main bearings, later.

[OddDuck]

Carrying on with the swingarm bearings, this time from the inside.

I had a go at getting the snap rings out and ending up drilling / Dremelling a channel behind them. They have an angled end so in theory they're liftable, but in practice forget it. Cut in behind the groove, get a screwdriver or two in to lever out, an Allen key to lift, and it's possible to work them out without twisting or bending them.

The internal seal was next. I'd originally tried leaving the snap rings in place and driving seal plus both bearings out with a socket and extension bar. Nope, forget it. All that happens is that the thin metal of the seal body collapses and then barrels, locking itself in tight. I had to go deeper on the grove and then cut through the seal's shell in order to break it, bend it, and finally yank it out. The other seal came out by using a washer on a length of studding, pushing it past the rubber lip into engagement on the seal's shell, and levering upwards. The long-nosed pliers are there to force the lower washer into place and then keep it there. A couple of positions pulled on the perimeter and it came away. The knife was used as a working surface to keep from denting the gasket faces of the crankcase half.

I didn't need a custom drift. A standard M6 mudguard washer turned out to fit over the swingarm Torrington bearing shells nearly perfectly, a socket set extension bar made for a nice driver punch.

[OddDuck]

Crankcase and swingarm bearings - the bakeoff.

Ducati's workshop manual specifies heating the half-cases to 100 C before driving old bearings out. I did a few dry runs with the slide puller I'd bought for the job, being sure of setups, then got to it.

First thing: a standard domestic oven has crappy temperature control, use a half-decent kitchen thermometer to check what's going on. It should be a thermistor instead of a bimetallic (the thermistors are usually good to at least 0.5 C) and keep an eye on it, don't just measure once. Be gentle with the thermometer stem in the oven door, it doesn't take much to crush or break these things.

Second thing: domestic ovens overshoot quite badly. Mine went up to about 140 C on the 100 C setting. Be sure before putting cases in. If that alloy has been through some kind of tempering process then you do not want to overheat it.

In the end it was actually pretty straightforward. There were a few trips between oven and bench. I had the cases in a couple of cheapo Briscoes $5 towels to keep the warmth in for as long as possible and wore welder's gauntlets ($15, why not) for handling. A couple of bits of two-by-four, checked for nails, served as the working brace surface.

The slide puller was used working upwards, I just put a gauntleted hand onto the casing to keep it from leaping all over the bench. The puller was pricey but made the job an absolute doddle, also kept bearings very nicely square in their bores during removal. Main bearings got punched out by using the puller as a guided drop hammer - I didn't try to fit the collet to the bearing (too small) but used it as a base on the bench for keeping the guide vertical, then hammered down. It didn't take much effort in the end, it really was just a couple of taps and they were out.

I could use a socket and hammer for one of the cylindrical roller bearings, as per standard mechanic's practice. I got stuck for what to do on the other pair, there's no obvious way to pull them, and they're in blind webs so there's no access to the back.

The pair of bearings on the clutch cogwheel came out easily with the slide hammer, too - there's not really any other way to pull them as far as I can see. There's a shim and a circlip in the center. Pull one bearing, flip the wheel, and pull the other so that it takes the oil seal with it.

[OddDuck]

Here's the slide puller being used as a drop hammer on the main bearings. It turned out that the hammer fit nicely into the main bearing's inner race, I didn't need an adaptor.

[pete376403]

100 degrees C is boiling water, so a water bath with an immersion heater would be a way of getting the temperature correct (more correct than your domestic oven, anyway)

[OddDuck]

100 degrees C is boiling water, so a water bath with an immersion heater would be a way of getting the temperature correct (more correct than your domestic oven, anyway)

True - don't have one though. Also don't have space to put one, I'm doing everything in a single car garage, with the car going back in every night. Power is via an extension cord from the flat. It's pretty basic.

One of the reasons I'm trying to document all the tips and tricks (and traps) is to help others, there's quite a few of us out there in a similar situation and I want to give something back. This isn't a go at you, it's just that most of us out there have access to an oven, but getting an immersion bath sorted out would just be too much.

[pete376403]

No, not at all, loving the thread. I have a semi derelict one car garage which is jammed up with stuff that's not worth keeping, but too good to throw away, so I know about the difficulties of work space and so on.
I bought up the water bath/heater idea cos many years back I had to replace valve guides on a Jag 6 and made a water bath out of a 45gal drum cut lengthwise, and a water heater element. Took a while to get everything up to temp but worked in the end.

[BMWST?]

olduck i have 2 peices of LVL offcuts at work 300x400x45mm. prolly overkill for a hard flat worksurface on your bench but it will be biffed anyway soon.

[OddDuck]

olduck i have 2 peices of LVL offcuts at work 300x400x45mm. prolly overkill for a hard flat worksurface on your bench but it will be biffed anyway soon.

Thanks but it turned out that loose bits of 2x4 worked just fine - the heating loosened everything up nicely. I still have M6 studs (for mounting the pickup coils) standing out in one case and I have to work around those for bearing insertion anyway, the 2x4's are mobile enough that it isn't a problem.

[OddDuck]

Waiting on bearings, shops aren't open to go look at bearing and seal drivers (turns out that you can buy them), so I've been playing with the airbox mod idea again. Well, the first bit, anyway: is it possible to move the battery?

Stock battery: no. It's a brick of a thing and the OEM location is about the only option that makes sense. Is there an aftermarket battery, and can it be moved?

After checking for matching / exceeding voltage, AHr rating, CCA, it turns out that Shorei make something. Model LFX 18 A1-BS12 MC, size 148 x 105 x 56 mm, can be placed in any orientation including upside down. It is roughly half the volume of the stock battery. Pricey but supposed to last long enough that it's actually cheaper in the long run. Well regarded brand too.

The first idea I had was to put a tray under the seat, in the current location of the crankcase valve's resonance boxes. These could be rebuilt in the new airbox. I modelled the Shorei up with cardboard, then tried a few variations on various designs for the tray.

It turned out that it's too constrained. The seat has a couple of forks at the front which latch into the frame. These set a maximum width, leaving very little room for vibration absorbing foam. The shock also runs too close to the front bottom corner of the tray's box. There's also a chance that the box could foul the hugger, if the rear shock takes a big hit and comes near to bottoming out. Finally, there was a flow to the design lines as the bike was, even on the underside - this box spoils it. No good, never mind, what about the rear light's mounting box?

First I tried up front and wide. No good, cable access to the rear was blocked, and the seat would have hit the battery tray - there wasn't enough vertical clearance. Then I tried to the rear, running lengthwise and flat. Success, there's room for wiring to the rear loom and the battery itself, there's space spare at the front, and I can put vibration isolators on the box corners and still have vertical clearance.

[Voltaire]

I've run a Shorai on my BMW racebike for about 2 years, total loss and I run it a day on a charge. I think you would need to swap out the regulator as the lithium batteries need a higher charge rate compared to the 'sloshers'
Weight is about 1 kg.
Liam http://www.fastbikegear.co.nz/ also does batteries too and my racing mate has these on his BMW.
The welded cracks on your frame seems to have a knock on effect with modifications
Great thread ( so far plonker free)

[OddDuck]

I've run a Shorai on my BMW racebike for about 2 years, total loss and I run it a day on a charge. I think you would need to swap out the regulator as the lithium batteries need a higher charge rate compared to the 'sloshers'
Weight is about 1 kg.
Liam http://www.fastbikegear.co.nz/ also does batteries too and my racing mate has these on his BMW.
The welded cracks on your frame seems to have a knock on effect with modifications
Great thread ( so far plonker free)

Don't say that, you'll jinx it!!

OK - the reg-rec unit is nothing special but my understanding was that the Shorai's would charge quicker but then require less juice. As far as I was aware they were as close as possible to a direct swap-in, just tonight I'd found that they arrive in an oversized box with lots of adhesive-backed foam so that an existing battery box can be padded up and used. Shorai themselves don't seem to mention anything about it. What have you heard about the regs needed?

Yeah, the frame repair is a set of dominoes alright... no wonder Ducati left the frame open, it's the only way to get everything to fit!

[pete376403]

You could put out a call to Ed about Shorai batteries but then the thread will be ruined as a useful resource.