Im at a complete loss. My bike has been sitting about a month since I last had it out, and after firing it up, and a breif warm up, I took to the street, and the problems began, as I twisted the throttle, I immediatly noticed a lack of power, and some lurching, and burping, so I came back home and parked it, My initial thought was spark but have cross checked everything except the coils, is there a way to check them myself? I pulled the plugs, kinda blackened, but not terrible, getting plenty of gas(still the weber) it has always been quirky at low rpms with the weber but runs great when its wide open, and all electrical connections are good, So I tried to fire it up again, this time, backfire, and after a battery worth of cranking, finally got it to run but very rough, and lots of thick grey smoke, it will not idle at all, and now it wont even start. any suggestions, could it be that the timing beltslipped? and if so did I do major damage to the motor trying to run it that way? Any help or suggestions in this matter would be greatly appreciated! Thanks, Chris

Chris,
You'll get a lot of help before the day is out. First; are both cylinders/pipes exhibiting the exact same problem? "Thick grey smoke" or is only one cylinder smoking? If both cylinders are smoking I would start with the Weber. It could be many things, but this carb is one place that can affect both cylinders. My feelings about this carb are evident from any post I've made. Throw it away. It is a piece of crap and was from the first bike off of the production line and is has given our Pasos such a bad rap. I would do this regardless of what you find is the solution to your problem. If it is the Weber, someone else will need to pitch in and help you, I disdain it so much that I won't even entertain learning anything about it. I'll give you my old one if you need it for parts though.
Next; Pull both plugs, put them in the caps and turn over the bike with them out and the plugs laying on the cylinder, examine the spark while turning over. This is actually not a good test of the coils, but it will tell you if you have too much oil and gas in the cylinder (leaked past the Weber) and at least you'll know if you have spark on both cylinders. If you pump out a bunch of oil and gas the carb is leaking past the float bowl. At this time do a compression check on both cylinders. Just buy a standard tool like you can get at any automtoive store. Others will probably know better than I, but I would want well over 85 PSI on each and they should be consistent. This will aleve your fears of a belt that has slipped. If a belt has slipped the compression will be off on one cylinder significantly and you may see and hear bad things in the spark plug hole. I doubt that this is your problem though.
Next; I would check the voltage at the coils. This is very important and when you are starting the bike this voltage should measure as near battery voltage as you can get. What is your battery voltage? It should be above 12VDV. Have you added the starter relay change out? If you haven't, your problem could very easily be a failing ignition switch or failing handlebar switch. This would affect both cylinders. I changed out my ignition coils for Dyna green coils they work very good and my bike starts and runs excellent without any hesitiations or burping. I highly recommend this change, but if both cylinders are exhibiting the same problem, it is probably NOT the coils as normally only one would fail at a time.
I'll check with you tomorrow, good luck
Doug

Coils can be checked pretty easily off the bike but I'm afraid I don't know what the correct measurements are.

You can check the resistance on the primary windins and also the secondary windings both coils should be the same (or there abouts)

Check also that your Low Tension voltage at the coils remains healthy when cranking then engine over. If iot suddenly drops well below twelve when cranking then there is another electrical gremlin further up the chain.

Try the wiring mods on this site for a fix to other Gremlins.

The importnant thing is to check the simple stuff first. I would suspect if your belt had slipped then you would probably be shooting bits of valve and piston from the pipes not smoke.
How old are the belts ?

Throw a new set of plugs in and start it up, New not cleaned plugs. Sounds like it badly flooded. The weber is not complete crap but darn close. It's what you have so getting to know it better will enable you to fix it.

To me is sounds like a stuck float needle that allowed the carb to drain into the engine. A quick way to clear the crap that gets stuck in the needle, is to disconnect or pinch closed the fuel line and start the engine. Let it run out of fuel and then reconnect/open the fule line and start it up again. The rush of fuel when the needle is at it's lowest point sometimes flushes the junk out. Check the oil level to make sure you don't have a quart of gas in the crankcase.

If a belt broke you would know it as the engine is an interference type. When the belt breaks Mr. Piston will meet Ms. Valve and make very ugly noises.

Good luck.

"Check the oil level to make sure you don't have a quart of gas in the crankcase"

Good for cleaning your oil filter screen :ugh: but not so good for long and happy running !

Thank you all for the response, this gives me much to try, I will repost later with updates, Chris

No, if the belt slipped one tooth, it probably didn't do any damage. But belts rarely slip, unless your tension is WAY off. Belts breaking do substantial damage, however... When mine broke last month, I only noticed a lack of power. Putting my hand over the bellmouths in the airbox revealed the true problem.

The compression test is a very good idea, but you should be looking for over 120, and within 10% of eachother. Note that you will need an adapter to put an automotive type compression tester on Ducatis. Bring a spark plug when you go to the store.

Jon is right, first thing is to throw new plugs in. If you don't like the cost of plugs, don't go to a dealer. NGK's from AutoZone work just as well.

I have noticed that Carb'ed Ducatis in particular don't like run on old gas. Old or new. After a month or so, the gas in the carbs has lost its' higher fractions, and the bike won't start or runs poorly. Just use a screwdriver to dump the contents of the float bowl. Then open up your fuel petcock.

Alright, Ive got some things sorted out, compression is good, 110 psi at each cyl. voltage good as well, 12.8 at the posts, and slightly lower at the coils but still above 12.0v, should this read higher? Also I believe your weber assumptions are right, tried clearing the float, no change, but upon inspecting the oil it is in fact gassy, though could be from repetitive attempts at starting with no luck, eh? I will mess with the carb some more, change the plugs and oil, and let you know, I have had the bike 2 years(4k miles) and have done nothing to the belts, its probably definatly time for a tension adjust too. Thanks again for all the help and I will post again soon. Chris

Well, I'm sure this has nothing to do with your problem, but if you have owned the bike 2 years and haven't touched the belts, it's time for new ones.

I wish I had taken a picture of the damage my 748 sustained from a broken belt. It's not pretty. If you had to pay a dealer to fix the damage, your bike would probably be totalled over a belt! New guides, installed, reamed, recut seats, new valves, valve seals, re-shim, reinstall.... Have I scared you yet?

Once again, if you don't like the cost of $50 for belts every 2 years, don't go to your dealer. Any decent bike shop is a Lockhart Phillips USA dealer. LP is big into Ducatis. Lotsa carbon and other goodies, but also maintenance items like Bucci belts, which are very good.

110 psi compression is on the low side, but ok. If the oil level didn't go up, I wouldn't worry about gas in the oil. I'd still try fresh gas, drain the carb bowl, and fresh plugs.

the clutch pack is the same as one of the newer bikes but i cant remember which one . i did not keep the packaging when i changed it sorry i cant help you any more than that.