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Discussion Starter #1
First post here - Searched previous posts but couldn't find one with this problem under my specific conditions:

I recently bought a 1998 M900 with 1700 miles on it. No mods except a Staintune exhaust / header, a tach kit, and a few carbon fiber bits. Obviously it wasn't used much over the last 11 years but it was immaculate and the dealer tightened & replaced anything that needed it before I rode it home. No problems in 500 miles except an oil leak (loose filter).

I was riding today, let it warm up, and then revved it to about 8k for the first time. Before this point it was running fine. When I stopped at the next light I immediately noticed that it was running rougher, popping, and backfiring here and there. When I accelerated away the engine would bog down and then rev up unpredictably (=bucking) and the backfiring continued. Fortunately I was only a couple of miles or two from home so I awkwardly rode it home without a major incident.

I don't have a lot of tools or much experience with Ducatis, but I'd like to check whatever I can myself before trucking it back to the dealer. Where should I start? Spark plugs? Also, could I have broken anything by riding the bike a couple of miles after the problem developed? Thanks for your help; I assume most of you can remember how you felt the first time your bike acted up :-(
 

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Discussion Starter #2
Changed the plugs out today but still having the issue. It also dawned on me that my battery is weak and needs charging or replacement. The starter strains a little but the engine does start - - could this be a factor? I thought that the battery was ruled out once it started, but I read on a different forum that if the battery is drained then the alternator will expend more energy to charge it, taking electricity away from the plugs. Any thoughts?
 

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To Bacci,
This is an old post but here is a reply to your post.

Your most likely dealing with fuel or air problem. If you have a stock bike, start by cleaning the carbs, checking air filter.
If you modded the bike exhaust or air box, than you need to rejet the carbs.

There are many other possiable causes, but these are easy and cheap things to check first.
 

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Cheers man.

to me it sounds like fuel or air too... will check it out.. can't stand bringing to the shop again and forking out on labour yet again.

Bacci
 

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First post here - Searched previous posts but couldn't find one with this problem under my specific conditions:

I recently bought a 1998 M900 with 1700 miles on it. No mods except a Staintune exhaust / header, a tach kit, and a few carbon fiber bits. Obviously it wasn't used much over the last 11 years but it was immaculate and the dealer tightened & replaced anything that needed it before I rode it home. No problems in 500 miles except an oil leak (loose filter).
How do the spark plugs cables look? Dry? Is the filter a hiper one? From my experience in cars, this is a fuel issue most probably, faulty pump, carb jetting or an air leak in the carbs...
 

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I had a similar problem recently on my M900.

It was fine for about 6 months, then started playing up (bucking and backfiring - trouble starting it etc). So I cleaned out the airfilter - changed the sparkplugs - still played up.

Because it wouldn't start and run, the battery went dead - my old man decided to jump start it from a car battery WHILE THE CAR WAS RUNNING - which ended up causing more issues.

Took it in, got it checked out because the coils ended up being blown, got the bike back, after about 15 minutes it started bucking again - decided to get a little bit DIY on the bike, removed and cleaned the carbies down as they were filthy and had orange residue inside them... bought a new fuel filter and hoses, cleared the carbies but the bike was still running rough.

Ended up checking the inside of the tank - had some slight muck and rust in it from sitting half full for a few months while I was sick - got the tank resealed - reassembled the carbies (had the spacing incorrect at first) and now it seems to be running fine.

My drama's all started with clogged carbies - I'd check there along with your fuel filter... It is a time consuming job.

Now my bike runs fine, but I noticed that the rear tail light and speedo lights don't work... off to check the fuses now.
 

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Discussion Starter #8
Hey Bleepblipblip; any luck in this.. I've got the same problem
Sorry I missed your question Baccci - - yes my bike started running normally after I replaced the plugs and charged the battery. I have a similar problem now, though, I think due to the bike being used infrequently during the winter. Planning on getting the carbs cleaned soon.
 

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Thanks bleepblipblip... I experienced exactly the same! winter seemed to be the problem. now it's running fine. Cheers
 

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Damn I bet my issue is the same. Except my bike is far from stock. I bought it this way but similar issues. Rough at any RPM seems to be worse on one cylinder which is more than likely that it's the one given me static.

As for the bike it has Keihin FCR 41mm on it and exhaust and I was told cams as well. Slip on exhaust and several other goodies. Here is a short video on how it runs. Check out the last few seconds cause it's hard to hear when I am on the right side of the bike due to the clutch being so loud. I am sure I am going to have to rebuild that soon too. Discs and pressure plates are probably warped. As well as notches worn into the basket.

Here is the vid.
 

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Discussion Starter #11
One thing worth checking would be the fuel pump. The old school vacuum pump is nice and simple but the diaphragm will undoubtedly weaken over time and fail. This turned out to be the source of many of my issues.

I don't have the M900 any longer, but I still love the bike. I have an 848 Evo now and while it is certainly fun to ride, it isn't nearly as intuitive or easy to work on as the Monster. What a classic bike :)
 

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Well I pulled the carbs and there is some trash in the tank as well as the fuel filter they had installed. The fuel flows pretty freely through the entire system though.

Anyone know about tuning the FCR carbs for this bike? That's what the previous owner had installed on here and I would be willing to guess they slapped them on and that was it.
 
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