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Discussion Starter #1
Hello DucHeads! I just bought the bike (1995 Monster 900 with Keihin 41mm FCR's) and am experiencing a surge from ¼ to ¾ throttle, as well as stumbling at low rpm’s, especially when starting out in 1st gear (have to really gas it and hoooold the clutch to make it through intersections, then it wants to buck me off intermittently if I gas it, and that holds true through all the gears).

It will not start without spraying starter fluid or gas in the intake unless it's good and warmed up. When cold, to start it I have to hold the throttle to keep it from dying for a good couple minutes until it warms up and idles on its own (with idle screw set high). It will idle fine after warm, but hesitates and sometimes dies if you whack the throttle.

Top end giddy-up is fantastic once you get past the surges, and I can cruise at 65-80 with very little trouble - it's everything else that is a major headache.

I first ran SeaFoam through the intake and fuel according to directions, then disassembled and thoroughly cleaned the carburetors when that didn't fix it, but the left pilot jet doesn’t appear to squirt any fuel in the intake (which was also the case before I cleaned them). Also did the following: fuel filter changed, battery charged, new Iridium plugs and the carb clean, but it runs the same as before (aka: rough!), so I need some help!

I’ve only done basic work on my bikes and am new to Ducati, so do I still have a plugged jet in those carbs, or do they need to be synched and/or the valves adjusted??

If it helps, my FCR settings are as follows:

Main jets: 155
Slow jets: 60
Slow fuel: ¾ turn out
Slow air: 1 ¾ turns out
Floats: 9mm
Main jet circlip: 3rd notch from top

My layman's mechanic knowledge is tapped out, and I was sure the SeaFoam/Carb Clean would have me back in business, but alas, nope.

Suggestions please!?!? Summer is here and I NEED to ride! I've read of weak coils, rectifiers, regulators, etc., but would any of those cause my trouble? Also, does the lack of pilot fuel squirting on the left side guarantee a clogged carb component?...I've torn them down twice and blasted the heck out of all needles/jets/passageways/hoses with carb spray then compressed air...?. Fuel seems to be getting through just fine and the new filter is clean. I loooove the bike, but it's teasing me to death so far! :think:
 

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I have a 96 and experienced the same problem with having to hold the throttle to get it to start. I fixed it by adjusting the throttle cable's. You might have some luck with this.
I know it will not fix all your problems but i'm new to ducati also (had my bike for about a year) just trying to share what little info i have. I'm sure some of these other guys on this forum will be able to help.
good luck.
 

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throttle bodies/carbs synced up?
what about valve clearances?
how many miles on the bike?
when was the last valve adjustment done?
never met anyone (car or bike owner) who liked iridium plugs. I am not saying no one likes them.
 

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Discussion Starter #4
Re: Throttle suggestion

Thanks for the reply, Corey (hilarious avatar, by the way). I'm pretty sure the throttle cables are good as they seem very responsive both on and when I let off. I'll take any suggestions I can get though.

ps: I just moved from cruisers to my first streetfighter/naked/sport bike, and I'm promptly selling my Suzuki Intruder 800, even though it's a great bike. The fun factor was too much to argue with (now if I can just get the Monster running right - I can only imagine the fun we'll have)!
 

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The way i checked my throttle cable was under the carbs. if the cable is way slack this could be why you have to turn the throttle to start. How much throttle do you need to start the bike?
 

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Discussion Starter #7
Re: Throttle cables

The way i checked my throttle cable was under the carbs. if the cable is way slack this could be why you have to turn the throttle to start. How much throttle do you need to start the bike?
Yeah, they're good. Hardly any slack. Throttle on, it snaps right to and roars to life, both at idle and on the freeway. Throttle off, it settles down like it should. Very responsive when I'm watching them right at the carb level, so it's gotta be something else...hmm
 

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Discussion Starter #8 (Edited)
RE: Throttle bodies/carb synch

throttle bodies/carbs synced up?
what about valve clearances?
how many miles on the bike?
when was the last valve adjustment done?
never met anyone (car or bike owner) who liked iridium plugs. I am not saying no one likes them.
Sorry, I forgot to list the mileage! Only 12k with records back to the 6k service.

I got the iridiums just to see if there was a noticeable difference. Still have the regular NGK's. I don't notice anything different, but it's running lousy overall so the verdict is still out on 'em, for me, at least.

As for the valves, I may have to bite the bullet and have it done since I'm at the 12k service interval anyhow. Last known adjustment was 6k (5 years ago!). My brother owned the bike the last 5 years and it ran great until he somehow "didn't have time to ride" and left it under its cover for the last 2 years. I'm now trying to resurrect it. The carbs were the obvious starting point with old fuel, and I'm still thinking the non-functioning pilot spray in the left intake is key...but I'm not knowledgeable enough to know the effects of a bike in need of carb synching/valve adjusting? Reading these forums is a crash course in Ducati maintenance for sure, but it seems like so many people have my same symptoms, but nearly every fix ends up being different! Makes me glad I'm not a motorcycle mechanic...oh wait, they get paid by the hour, huh? :p
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Also, George, I used that Keihin tuning guide as much as I could, but admittedly a lot of it was more than I was willing or able to tackle right now. Figuring out the the carb settings wasn't hard, but it appears that what I've done is only part of the tuning process, and dependent on the valves, synch, etc. Might be time to ante up at the Duc shop *gulp* and report back when they troubleshoot it...but before I admit defeat, I'm going to get some B12 and soak them for a bit, then really focus on the pilot jet. Is it possible that if this little guy is clogged it would keep me from a) starting w/o throttle, b) smoothly accelerating at all but the high-high end and c) not idling on its own until very warmed up? Hard to believe, but is that all possible? Or would un-synched carbs cause all the same things? It tries to pull like a demon still, but surges all the way through!
 

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Discussion Starter #9
Quick update: I cleaned the snot - literally - out of the carbs, this time finding a TINY little passageway that led to the clogged pilot spray, poked a .010" and .017" electric guitar string in both sides and every other orifice I could find (on the carbs :eek:), partially soaked all the metal parts in Berryman B12, sprayed more carb cleaner in every hole and then compressed air. I also opened up the accelerator pump for the first time and found some crud lodged under the teensy weensy o-ring (that I almost dropped in the gravel!) as well as the little rubber diaphragm.

Haven't fully tested operation yet, as I had to go get more gas to dump in the tank and it took a bit to prime the intakes to draw the fuel through (which had gotten quite low). With good fuel flow I could only get it to turn over by feathering off and on the throttle, holding the throttle steady at 1/2 twist when it fired just to keep it going (as soon as I let off she coughed and died like before). This is also with the idle screw up all the way. The good news is both pilot sprays work now, so the left one had definitely been clogged despite my earlier cleaning efforts.

Now the bad news: within 10 seconds of getting her fired up strong and holding the throttle at 1/2 twist or so, I get this rapid series POP! POP! POP! *biff* POP! POP! POP! and so on. The pops are all out the mufflers (Termignoni carbon slip-ons) and the lone *biff* was an intake burp. They were so loud and obnoxious that I had to let off before the neighbors rioted, and now I'm wondering what twisting and turning can be done on the air and/or fuel screws and why the darned thing won't start without so much throttle help!?
 

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Discussion Starter #10
Another update: I cleaned the plugs, dialed the fuel screws to 1 1/2 turns out and the air screws to a 1/2 turn out, idle screw on high (these are the base settings for the Flat Side Carbs with the Sudco kit). Pushed the starter button (with NO throttle, I might add), and VAROOOOM, thumpa thumpa thumpa thumpa...

Took it out for about 20 minutes, including a freeway stint and here's where I'm at: still a slight hesitation from stops, but I don't have to gas it like before to keep from dying. Lower rpm's are uneven and a surge still exists when moderately getting up to cruising speed, at which point it smooths out considerably, and will go like mad in the upper ranges. That's not too much different from before, but it is still a marked improvement, thank goodness.

I'm inclined to take it in for a valve adjustment and have the carbs synched and tuned at either Ducati Seattle or Eastside Motosports (any recommendations on which one I should visit, NW riders?). Having at least resolved the clogged pilot fuel line issue, I don't mind letting the pros have a go at some of the more difficult tasks. I'm considering one of those Dyna Coil sets from CA-Cycleworks as well to give the ol' lady a hearty kick in the pants.
 

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i havent had to adjust the valves yet, but checking them is super easy, 5.00 for the shims if they dont need adjustment then this will save you $$$
 

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Discussion Starter #12
Great, thanks for the tip. I'll have to look more into doing that myself possibly. I hate the thought of paying $90 an hour (plus parts & tax) when it's within my capabilities - even if it takes 3x as long!
 

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There's nothing like the satisfaction you get from checking and adjusting the valves on your machine. Pro Italia sells a video on how to do it. It explains everything and shows you the necessary tricks to save time and do it accurately.
Here's a link.
http://store.proitalia.com/vid1.html
It'll be the best $20 you ever spent.
If you need to replace any of the shims, get them from EMS.
http://www.emsduc.com/
They're super fast on shipping and their shims are priced way lower than the dealer.


George
 

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Discussion Starter #14
Hey George, I feel like I should send you some of the money I'll be saving. This forum is fantastic!
 

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Hey George, I feel like I should send you some of the money I'll be saving. This forum is fantastic!
Brian,

Glad to help someone willing to get their hands dirty and report back on their progress. I have a '95 M900 also that I bought new as a leftover in '96. After 13 years and over 74,000 miles, it still makes me smile when I ride it.
If you decide to take a stab at the valves, I've found that removing the gas tank, battery and battery base rubber makes it much easier to work on the vertical head.
Good luck.

George
 

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Discussion Starter #16
I got tired of cleaning the carbs (3 times!) and troubleshooting the darned thing for the surge/stumble problem, so I bit the bullet and brought it in to Eastside Motosports in Bellevue (WA). Just got a call, and after 3 hours of diagnostics (at $90/hr) they've narrowed it to the Accelerator Pump on the Keihin FCR's. The rebuild kit is $39 + s&h from Sudco. (They also said the coils were weak, which I suspected, but not the cause of my problem.)

Hopefully this will be the final piece to the puzzle so I can stop working on the bike and actually enjoy it for a few months this summer! I'll post the final results here in case anyone else encounters similar troubles and needs an idea or two.
 

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Discussion Starter #17
Long overdue update!

We had our first child just after getting the bike back from the shop, so I forgot to post an update. First of all, Brian in the Service Department at Eastside Motosports in Bellevue, WA, may have the worst customer service skills I've ever come across. He spoke in monotone, never smiled, seemed disinterested and put off by my being there, and generally made me hate living. :eek: In stark contrast, however, Shawn was fantastic in every way, even giving me a last second "pregnancy special" (ie: slashing the diagnostic bill by nearly half!). Totally redeemed the experience for me. :D

Anyhow, I picked the bike up with the carbs disassembled and the mechanic's suggestion that I just buy a new unit instead of trying to isolate the faulty part causing the surge, potentially spending as much in the process. Seeing as how a new Keihin 41mm FCR carb kit runs nearly $900, I was pretty crushed. However, I can hopefully recoup some of my costs selling this one for parts or to someone who wants to troubleshoot it.

After letting everything sit in the garage for 3 months, I took a couple hours and put it all back together just for the heck of it. Started right up, but sadly, still had the now-familiar surge. Still, I went on a good hour long run, most on the freeway doing 70+, and all-in-all it's not that bad. In fact, when I'm on the throttle hard in any of the gears, after the initial hiccups it really goes hard.

All that to say, I'm saving for a new Keihin carb set and will sell this one if anyone is interested. I'm not sure why, but the shop threw in two replacement float kits, so whoever buys these carbs will get that too.

I'll do a final update here when I put the new carbs in to (hopefully) marvel at what it's like to ride the Monster running 100%, which I have yet to experience! :rolleyes:
 

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>>Anyhow, I picked the bike up with the carbs disassembled and the mechanic's suggestion that I just buy a new unit instead of trying to isolate the faulty part causing the surge, potentially spending as much in the process. <<

And from what you wrote above, you believe them?!?

Don`t give, up try again!

Try different starting point:
I (& several friends) run w/o acc pump.
Remove it`s lever & try the settings you had in yor first post + raising needles 1 notch.
Cheap & nothing to loose!
 

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That's just a lazy (or incompetent) mechanic, possibly one not fully trained in FCR servicing. Don't just buy a whole new FCR set up because of them just yet!

I love it when a "pro" just says to replace stuff when they're mechanically stumped. You could have determined that yourself by now. You paid them how much money for them to do nothing at the end of the day.... and if buying a new set up doesn't fix your issue, where are you at now? I'd try another shop who knows those carbs better and have them properly serviced. Call around
 

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Discussion Starter #20
Attribute it to my relative inexperience. I was definitely frustrated to pay 300 smackers and get nothing but the bike back partially disassembled. I did not meet the mechanic in question but supposedly he's been certified on Ducatis for nearly 20 years...so who am I to question, you know?

I am curious as to their original diagnosis of a faulty accelerator pump. Maybe they swapped it out with a working unit and it still had the hiccup so they poked around, hoping for something obvious, and nothing jumped out so that was that??? I hate to think a trained tech would just give up like that.

I just remembered that they also mentioned that either the rubber gaskets or the hard sealant stuff that joins the main body could be failing to seal completely, and at that point they suggested to replace the whole thing (versus all the seals - and who knows what else?). For peace of mind I thought it did make sense to pay $900 for a new unit than piece one back together for half that (on top of the $300 diagnostic I've already coughed up) and still not be sure I've narrowed it down...

However, since I like keeping my money in my wallet and I don't mind getting my hands dirty, I'll give your acc pump trick a try whenever the sun decides to come out again here in Seattle (where we rust instead of tan).

Thanks much, fellas.
 
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