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1994 900SS CR, 2002 998 Trackbike
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Discussion Starter #1 (Edited)
I just received a set of banked FCRs from a fellow forum member, to be fitted on my 900. Guess everyone bites that bullet sooner or later..

These apparently originally came off someone's 1000DS build, and must have been in storage for a year or three, so there is some work to do.

- Looking at the accelerator, I'm not sure if the pump linkage is correctly assembled? If it is, I can't figure out how it is supposed to work.. is that black plastic triangle the right way up?

- I may be able to get jets locally, but have to order most parts in the US so there is a bit of lead time and shipping costs. I'm getting the usual gasket/rubber parts, as well as a pump rebuild kit, anything else I should buy?

- bike is a 900 with 92mm 11:1 pistons. Stock heads and cams. Exhausts are stock pipes with cored cans. I'd like to try the Uni pod filters that came with the carbs. Based on what I have read here, I will start with a 155 or 150 main jet. Needles are EMT currently on the 3rd clip. Pilot is 60 and main air 200. Does that sound reasonable?
 

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Try reading this: Keihin FCR FAQ - it gives the base line jetting that these carbs start with for the 900's. FWIW - mine is jetted pretty much as per the link, but my idle mix is at 2-3/4's, and main jet at 180. Air screw at about 2-1/2. These are NOT dyno'd settings, but seat of the pants and open road full throttle testing. Works OK for me (with my exhaust and airbox setup), and I get 20+kms/litre. The 'Ride Video' I posted a day or two back should prove that the jetting is good enough... YMMV.
 

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I just received a set of banked FCRs from a fellow forum member, to be fitted on my 900. Guess everyone bites that bullet sooner or later..

These apparently originally came off someone's 1000DS build, and must have been in storage for a year or three, so there is some work to do.

- Looking at the accelerator, I'm not sure if the pump linkage is correctly assembled? If it is, I can't figure out how it is supposed to work.. is that black plastic triangle the right way up?
It looks correct. Do a Google image search for Ducati FCR and you'll find plenty of images to confirm it. It's totally safe for you to manually turn the throttle cam and see the rod push the plunger down.


- I may be able to get jets locally, but have to order most parts in the US so there is a bit of lead time and shipping costs. I'm getting the usual gasket/rubber parts, as well as a pump rebuild kit, anything else I should buy?
I read somewhere that Keihin recommends changing the vacuum plates periodically. These are the metal plates that go on the back side of the slide and are pretty pricey. You'll know if you need new ones once you get the slides out and go to change the o-ring on the plate.

- bike is a 900 with 92mm 11:1 pistons. Stock heads and cams. Exhausts are stock pipes with cored cans. I'd like to try the Uni pod filters that came with the carbs. Based on what I have read here, I will start with a 155 or 150 main jet. Needles are EMT currently on the 3rd clip. Pilot is 60 and main air 200. Does that sound reasonable?
That'll be enough to get you going for sure. You might need to fiddle with the slow air screw to get it to idle. I believe the EMT needle is baseline. I went with the EMR on mine to enrichen the fuel slightly, along with a 155 main. I assume you have already pulled out some timing for your high compression pistons, a little extra fuel can also help quench some heat from the cylinder, but it's not necessarily the best solution.

I assume you're familiar with the eccentricities of these carbs on our bikes - no choke means cranking up the idle and pumping the throttle to wet the throats with the accelerator pump as an "enrichener" to start the bike, and even then as it gets colder outside it becomes increasingly more difficult to start, so be sure you have a healthy battery during the colder months.
 

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I assume you're familiar with the eccentricities of these carbs on our bikes - no choke means cranking up the idle and pumping the throttle to wet the throats with the accelerator pump as an "enrichener" to start the bike, and even then as it gets colder outside it becomes increasingly more difficult to start, so be sure you have a healthy battery during the colder months.
Never an issue in Dubai :wink2: But when I eventually shift back to NZ and join SteveB and co I’ll have to improve my modest understanding of these bikes. One thing I do know, you’ll grin - a lot, when you get it going with those bad boy FCR’s.
 

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1994 900SS CR, 2002 998 Trackbike
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Discussion Starter #5
Thanks. The pump rod does go down a bit when I open the throttle, it's just that the plastic part is on the opposite side of the metal lever. So the lever doesn't actually push the plastic part, instead it just gets out of the way if that makes sense, and the plastic part is rotated by spring force only. It doesn't seem to push down (pump) very far, that's why I'm wondering. But my pump diaphragm is also pretty stiff and cruddy so that could explain it.

I'll take the slides off and check the vacuum plates. Maybe I'll order the richer needles as well, $10 each isn't bad. I'm at sea level and it's generally cool here, so I'm sure I'll end up on the richer side of things.

I have an ignitech and run slightly retarded timing for the hi comps. Would be nice to have a TPS for the carbs actually... Or is that worth it?

And yes I'm familiar with the lack of choke. Pump the throttle to prime is how we start carburetor aircraft piston engines at work, I assume it'll be similar here. Couldn't be any harder than when I bought the bike, and it had mikunis with the choke jet blocked off.
 

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39 or 41? it makes a measurable difference to main jet selection at least.

i'd fit a pilot jet in the region of 50 and an emr or ems needle.
 

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1994 900SS CR, 2002 998 Trackbike
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Discussion Starter #7
41s. I'll add some needles and a smaller pilot to my order
 

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You probably will want a range of jets to start, to be honest any jet sizes you buy are a guess. I have jetting notes from many years of jetting these bikes and though some used the same jets there are many pages with "A bike" that needed different jets,needles than others. You should start with the average jets for the same bike/mods you have and then know it is only going to get you close. Closest comes from dyno time and air/fuel being recorded. Most people are happy enough with close so as long as you can get there you should be good enough.
 

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1994 900SS CR, 2002 998 Trackbike
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Discussion Starter #11
I have 152, 158, and 165 mains now. It'll take me a couple of weeks until the bike is ready for runs, but when the time comes I will probably actually take it to our local motorcycle dyno.

My dad is currently 3D printing some new intake filter adapters for me as well. I'm hoping to get about 50mm total length, with a slight angle built in so the filters fit better under the tank. Only question is if the ABS will be heat proof enough to survive down there.
 

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If you are talking about air filter adapters i would think you would be fine but as you suggest just keep an eye on them. Make sure the jets you buy are genuine Keihin brand and if the dyno shop has them on hand I do not even think I would spend the money yet. Jets are cheap, it is the expertise you are paying for they should get you in the ball park and then you should have a air/fuel chart for you to buy the jets in the direction you will likely need if you do play later on.

I would have a couple options as to the filters so you do not waste time at the dyno, time is money so do not waste any of there time (and your money). They should quickly see a direction that will be best , ** with the parts you bring**. This does not mean they will be the best parts just what they have to work with and they will likely jet to maximize with that. Keep in mind that you can kill HP with a air filter that is not well designed such as the ones attached, they cost a 996 close to 10%.
 

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