Winter Layup - 1995 Ducati 900 Supersport

[OddDuck]

Keihin flatslides: I reckon they're awesome but the as-arrived tuning is probably dicey. That said, they've worked out very well for me... power improvement would have to be dyno'd (together with decent tuning) but for me at least there was one hell of an improvement in rideability, straight out of the box.

[Voltaire]

Voltaire - good to hear, but... sorry I'm going to be a fussy bastard here...

Check your plugs, I suspect that it'll run super rich once warmed up if it's starting without choke. Surprising amounts of heat coming off the engine is something I've been through already and it was associated with running over-rich.

Airbox and filter medium (or lack thereof) will affect starting and idle quite markedly, if you got it tuned for starting with these removed then it's going to be a bit different with them fitted. At least the pilot fuel jet screw is accessible easily, it shouldn't be hard to tweak it again if necessary.

If the plugs are fine then ignore the above, just ride the thing.

Good points, will back off idle mix next, check the plugs and see how that goes.
Be nice to have it sorted as being a hard starter means its at the back of the queue for rides.

Monday: Ambient Temp 20 degrees according to on bike guage, would 'catch' with no choke but die, part choke started and idled, choke off after a min and idle.
No unburnt fuel smells from zorst. Best cold start ever for that bike

I spent a lot of time sorting out my Guzzi carbs and its pretty good but does not like running low road speeds to too long ( aka Vintage Bike run)

[Voltaire]

Keihin flatslides: I reckon they're awesome but the as-arrived tuning is probably dicey. That said, they've worked out very well for me... power improvement would have to be dyno'd (together with decent tuning) but for me at least there was one hell of an improvement in rideability, straight out of the box.

I found the rideablity excellent with mine, just did not like starting.

I probably have too many bikes that need attention so the ones that go and don't cause bother get used....BMW's mainly

Dyno tuning is the way to go

[OddDuck]

Thanks to donations of low voltage heater wire (thanks Pete) and finally getting some spare time and energy, I had the first go at the inlet manifold heaters and a cold start test tonight.

Basic specs: heater coils are 1 ohm each (cold), that works out to roughly 74 watts if they're run in series off 12V. Power supply was a mostly-rooted battery that I hadn't got around to disposing of yet. The setup's basic. It's fast, cheap and nasty. That's deliberate, there's no way I'd go on the road with something this rough... this is a simple practical test and nothing more.

Right, before people get their hopes up: it failed. It didn't warm the inlet manifolds up more than about five degrees and there was no success at cold starting, when I gave the starter motor a few cranks to see what'd happen. I did learn a couple of things, though.

1) that old battery really is stuffed, I'll have to sort out a mains 12V / 6 A power supply with a short circuit protection for any real testing. Power will have to be applied for at least five minutes continuous. This sort of time will have to be drastically reduced for any real world system.

2) thermal coupling between the heater and inlet manifold is very poor. A layer of insulation over the top would help, that's an option for later, but I think that what's really needed is for the heater wire to be completely buried inside aluminium. For that I'll have to machine something up.

[OddDuck]

Tonight's effort was to try to insulate the manifold heating elements, and (second) to try heating the carburettor bowls.

A spot of muffler wrap cut to size, a hose clamp to hold it on, and I connected a borrowed 10A-capable power supply to the heaters and had at it. Findings:

1) the manifolds get quite warm at the carburettor end, less so at the cylinder head
2) even with the insulation on, this setup still takes a good five-ish minutes to heat up
3) peak temperature was approx 40 C at the vacuum gauge screw head, this was with roughly 36 watts of heating
4) it helps starting but there's no way it's an instant roar-to-life solution.

It does help. Ambient was 13 C. At this sort of temperature, previously I'd have had all sorts of fun and games trying to get the engine to catch while cold-starting. I was deliberately not using the accelerator pumps to squirt petrol down the inlet manifolds before cranking the motor, it took a bit of cranking but the motor did start to catch, much sooner than usual.

I then tried using a very cute pair of 40 W cartridge heaters (for 3D plastic printers) on the carburettor bowls. There a quite a few of these floating around these days, they're useful little beasts. Purely by chance, these fit into the idle mixture adjustment screw's bore quite nicely.

Initial tries were very promising - it didn't take long to warm the carburettor bowls up to approximately 25 C, and starting did seem to improve - but I can't take the results as definitive. The cylinder heads had warmed up quite a bit from previous cranking / starting / idling, and this would have helped starting too. The real test is with the motor overnight-cold.

[OddDuck]

Reckon I might have a result.

Tonight I tried starting from cold (14 C) with the twin 40 watt cartridge heaters in the carburettor bowls only - no power applied to the inlet manifolds.

I ran these heaters up until I got 30-ish degrees on the carbie bowls and then tried the starter.

Instant start and run, no issues with idle, the motor caught straightaway. No tricks with using accelerator pumps to prime. This was exactly the result I wanted.

I've now removed the experimental gear and put the fairings back on, I'm happy enough with this result that I won't try running inlet manifold heaters and carb bowl heaters together again. There's really only enough oomph for 80 watts anyway.

So, now to figure out a way to couple 40 watts into the carbie bowl and thus the fuel... It looks like the way to go is to make some kind of replacement for the 14mm hex drain bowl screws, something carrying both the heater element and a temperature sensor. That'll involve detailed measurements of the Keihin original part and then designing and machining something, but once made, it's a screw-in, bolt-on modification.

[OddDuck]

About a week ago I'd bought some sensors and thermostats off Amazon. I got around to testing them today.

First up was this wee beastie: www.amazon.com/gp/product/B00C2NQ83Q

About a year or so ago I'd been on a ride in the Wairarapa when the battery charge warning light came on. I pulled over, left the motor running, checked the headlight and sure enough it was dim. I'd been through this once before, much closer to home. The charging system wasn't working. The charge warning light only comes on once voltage is down below 11 V, in short, once most of the battery charge is already gone.

Uh oh. Abandon ride, switch headlight off, just try to get home. I nearly made it and had to get a jumpstart at Caltex Rimutaka (always look for a bloke with a ute, they've always got jumper leads). In the end I made it back without the need for a tow, but Ducati's warning light system really did leave something to be desired... I needed to know immediately when the rec-reg or the alternator (or both) failed.

Hence the little voltmeter. There are a few of these floating around, very simple devices with two leads that serve for both power and sensing. If I'd had this on the dash then I'd have been able to see in real time what was happening with battery charging.

I did want to test it first though, hence the setup on the bench with power supply / test voltage unit and high-end DVM borrowed from work. The little meter aced it. I won't go through the table of numbers, it's enough to say that the meter is within 0.05 V anywhere between 6 to 15 V. It's well within the accuracy I need for this kind of work. Supply is around 20 mA so it won't load the loom up significantly.

The next goodie was this: www.amazon.com/gp/product/B00D7AEKMO

I'd bought two, intending to check various temperatures through the inlet system and on the engine while riding. I only powered one up and immediately decided that I didn't want these on the bike. The reading dropped to 0.00 occasionally, the display was twice as big as the voltmeter, and the blue LED was way too bright. Various reviews had said the same. Red LEDs next time. Oops.

There were also thermostats, these being very simple on-off temperature controllers that switch a relay: www.amazon.com/gp/product/B00K75QRZA

I got 3 of them. I tested the thermometers as via the photos, in a pot of water on the stove against a couple of trusted thermometers, one a professionally calibrated unit borrowed from work. The probes are widely separated in the pot, hence the use of an eggbeater to drive turbulent stirring of the water.

They're quite good. Basically, between the different thermal lags of the probes and the unknown uniformity of the water temperature, I couldn't pick any significant difference in reading. It was far from a complete, pure, scientific test, I should have started at 5 degrees with ice water and worked my way up from there, stabilising the temperature at various intervals and running the reference thermometer around the pot to check uniformity as well... but stuff it, this'll do. Within a degree would be good enough and I think these are within 0.5 C or better.

The thermostat has a delay (hysteresis) built into its switching - it'll go past setpoint, either up or down, before it flips the relay. I guess this is to avoid buzzing if it's got a fast load of some kind. Anyway, the relay's there to connect a fan or a heater to power, it's got a digital setpoint adjustable via pushbuttons, all I have to do is put the thing into a weathertight box of some kind and I'm away.

[BMWST?]

why not a mains supply set up to warm things up when at home.probably the most common scenario anyway.Cold Kiwis and the like might require a second battery?

[OddDuck]

why not a mains supply set up to warm things up when at home.probably the most common scenario anyway.Cold Kiwis and the like might require a second battery?

Sometimes I've taken the bike to work and the day's got cold, sometimes I'm on the road on a multi-dayer and it's first thing in the morning in an unfamiliar town. If it's on the bike as part of the bike then it's with me.

When finally built and installed, it'll be something small, cheap and light. It'll be simple. The amount of work I've put in will look ridiculous but this is one of those jobs where most of it is finding out how to do it.

[BMWST?]

Sometimes I've taken the bike to work and the day's got cold, sometimes I'm on the road on a multi-dayer and it's first thing in the morning in an unfamiliar town. If it's on the bike as part of the bike then it's with me.

When finally built and installed, it'll be something small, cheap and light. It'll be simple. The amount of work I've put in will look ridiculous but this is one of those jobs where most of it is finding out how to do it.

sure is it is an interesting read

[pete376403]

What size battery does the bike have? 12volts and 40 watts should be around 3.3amps. A good battery should be able to handle two of these for a few minutes or more, seeing as now it's not going to cranking the starter motor for extended periods. Maybe you could look at a lithium battery, as the initial discharge running the heaters would bring up the voltage for the stating/running duties (if I understand how those things operate.)

On another topic - do you have any skill in programming? Does this mean anything to you? "The program is written in C.

The sensor output is applied to a 10 bit A/D convertor. The A/D results are processed via an exponential running average filter. 300 samples are taken at 20ms intervals. Next a mean average is taken of the middle 10% of the samples. This result is then displayed." and

"I used a 18F2685 for the gas gauge. It's mostly overkill, but I had some on hand from another project. Plus, it's better to have too much room for program and memory than not enough!"

[OddDuck]

Hi Pete,

The bike battery is a brick, a 12V 14 Ahr Katana (a Yuasa made with recycled materials). It's heavy, but I've had one before which survived horrible abuse (repeated run-flats during winter etc) so I've decided to stay with them. It's got plenty of capacity for running 80 watts for about thirty seconds, which is the target for the cold-start system.

With your question about C programming: no, I made a life decision two decades ago to stay the hell out of programming, I have not regretted this choice. That said I can answer some of it:

The sensor output is applied to a 10 bit A/D convertor. The A/D results are processed via an exponential running average filter. 300 samples are taken at 20ms intervals. Next a mean average is taken of the middle 10% of the samples. This result is then displayed.

It's a basic technique for screening out electrical noise.

The sensor (whatever it is) is analogue; it'll be putting out a voltage or a current in response to environment. The trouble is that the output has to come out from inside a casing and then be transmitted over leads. Casings and leads can be affected by magnetic fields, radio, thermoelectric effects in the leads, capacitive coupling from nearby electronics, that sort of thing... there'll be noise spikes up and down all over the signal. The spikes may actually be bigger than the signal, but they'll usually be centered on it.

A / D converter: a device that takes an analogue (linear) signal and converts it to a set of digital levels, i.e. a number. Once this is done, the signal is no longer anywhere near as vulnerable to outside noise because there's a very high difference between a 1 and 0; in digital systems these are expressed as voltage levels. O is usually 0 to 0.2 V, 1 is usually 4.2 to 5.2 V. It takes one hell of a noise spike to interfere with that, which is the big advantage of digital.

Exponential average running filter: Probably a microprocessor doing some magic. The bit that's important is that it takes 300 samples, which still have the noise from the sensor all over them. The A / D can only work with what comes into its front end.
The filter grabs the lot, looks at the spread of the results, then grabs the 10% in the middle, averages those, then displays that number. The digital output would be unreadable without this filter, the display would simply be trying to show a different number every 20 ms. As it is, if I read this right, the display should update every 300 x 0.02 s = 6 seconds, so it'll look a bit slow in responding to change.

This kind of filtering is always a tradeoff between minimising noise and retaining a fast enough response, so it's usually tuned for the type of sensor and the usual operating environment.

I used a 18F2685 for the gas gauge. It's mostly overkill, but I had some on hand from another project. Plus, it's better to have too much room for program and memory than not enough!

Google 18F2685 - I think it's probably some kind of integrated circuit, likely a microprocessor and memory chip. It's probably not a gas gauge, it's a device used to read one.

[pete376403]

Thanks for the input. The item in question is a fuel gauge that was designed and build by a guy on advrider.com. It used a pressure transducer(?) measuring the weight of fuel in line from the tank, and from there calculating and displaying the amount of fuel left in the tank. From there it morphed into a multi function display for temperature, road speed, gear position, and possibly more. The designer said he would post schematic and code but the thread went cold in 2015

http://advrider.com/index.php?thread...gauge.1016872/


we now return you to your regular scheduled program "Winter layup"

[OddDuck]

A few observations and thoughts from the last few weeks... I've been obsessing over the temperature control issue on inlet manifolds and carburettors (namely that there isn't any) and possible ways to build something for this.

Something that I really should have realised earlier: the famed Ducati L-twin is about the only popular motorcycle engine that has its carburettors or injectors ahead of the cylinder heads, once slipstream is considered. Inline V-twins, transverse V-twins, flat twins, inline 4's, triples, parallel twins, singles, virtually every other bike I can think of has its carburettor/s or injector/s behind the cylinder head. I.e., in the warm.

I think that there is a temperature that fuel likes to be at, before meeting air and being inhaled by the engine, and it's a bit warmer than normal NZ ambient.

At least I think that's true in my bike... crossing the Rimutaka hill, descending to Featherston and meeting sudden warm air, there was a clear transition between temperatures. The bike had been running OK, in roughly 15-ish ambient. Not great, but OK. Then we rode into air at nearly 25 degrees and quite suddenly the bike ran super smooth, then continued to do that for the remainder of the ride.

Tonight I took the bike into town and back. It's cool outside, not cold, but on the way back it started to rain. The handlebar tingle came back on the return journey. The bike hadn't been running quite right the whole way. I tried checking the carb bowl temperature (just by hand; didn't have the imager with me) and found it cool to the touch going into town and very cool coming back. It was below ambient on both occasions.

So... it's getting late, I'm getting tired. I'll carry this on tomorrow. I'd run calculations of the heat energy needed to vaporise the fuel, but maybe it's worth also calculating how much heat is needed to raise the fuel to vaporising temperature in the first place.

[FJRider]

A few observations and thoughts from the last few weeks ...

Those changes could also be made (explained) by a change in air pressure ...