[Ducati] 900SS - Wits End

Sat Oct 27 12:10:02 EDT 2007

Good stuff Rich.  Many thanks.  This may turn into a fun project when I can
get to it.

Alec

On 10/27/07 7:02 AM, "Rich Roberts" <bigredxrunner at yahoo.com> wrote:

> Doesn't have to be propane about any volatile spirit will work like brake
> cleaner  etc etc.
>   As others have said, going back some years and I doubt I saved it but
> someone years ago documented the results of many many changes to 900SS, it
> almost read like a scientific paper. the result the single biggest effect
> resulted from use of Malossi intakes. In fact if you wanted to get within
> shouting distance of 90hp it was a necessity.
>   The FCRs will require a bit different starting routine but once you have it
> it generally will not be a problem. they will waken up the bike quite a bit in
> my experience. Used to be an outfit in Arkansas or somewhere down that way
> that sold those Malossis. Buddy likely remembers the guy.
>   But if you only want to get what you have running right. CVs can be made to
> work fine. It usually does not take much, When I have no idea I usually go up
> on main, slow jet and shim needle and see how that does. I have found in many
> bikes jetted EPA lean this almost always is an improvement over stock,
> sometime the increase in main and slow needs to be two sizes up. I have found
> in many cases something like this actually works better than new carbs. On my
> wifes DRZ when I was unhappy with the FCRs and full ti exhaust etc pulled it
> all off took stock carbs and went up on the main and slow two sizes shimmed
> needle and it ran and started like a champ, and this bike for whatever reason
> was always cranky as hell starting, very lean jetting. Also the slow jet was
> so small it frequently clogged with microscopic something, meaning I could
> never see anything in it but when I blew it out with solvent and put it back
> together it always ran and started better.
>   Some folks may be more scientific in their appraoch to these things, my
> approach has usually been see what others have done and try something and see
> how it does. never overlook the significance of slow jet. I have learned over
> the years focusing on main and needle often seems perplexing, meaning nothing
> you do will sort out problem, but increasing slow jet and bam, problem solved.
> Seen it several times...cause jetting overlaps, it is not just this or that,
> as you transition across the circuits those circuits overlap so at WOT it is
> mainly the main jet but other jets are doing a little as well esp as you roll
> on the throttle.
>   Your problem can be many minor things or jsut one.
>   My approach has always been to take apart and clean thoroughly, blow out
> everything with electromotive parts cleaner being very careful with gaskets
> which genrally do not like strong solvents, nothing like having a bowl gasket
> grow on you. And go up on main and slow a size or two. lots of singles and
> twins seem to be very forgiving of such course adjustments, meaning you would
> be surprised, runs ok, but runs better but both may work better than stock.
> Jets are cheap, local Suzuki dealer usually lets me go through their box of
> jets if i am looking for a couple, I usually have a hundred or so assorted
> jets from years of messing with this stuff and many Dynojet kits or Factory
> kits. So it makes it easy to try things.
>   i am not saying you have an airleak but it cant hurt to check, it likely is
> jetting. When jetting is off all sorts of fugged up things happen, from poor
> starting, does not want to idle, runs on, stumbles...usually not because jets
> are too big unless you did that yourself. Trash in a jet can do it as well.
>   If main is not right often you can tune out some of that with the air screw,
> pilot air screw etc. But if making course adjustments and little happens that
> is indication that you neeed to change main. this is partly why a couple main
> size differences will work, even there is overlap using air screw.
>   Also seems to me much writen in past about emulsion tubes on some of these
> bikes wearing out from the needle working in them over time, Change emulsion
> tube and problem goes away. I am no expert on emulsion tubes but clearly they
> are important, important enough that in some cases where a stock carb does not
> have one, Dynojet will actually inclde themn in their kit. Seems to me years
> ago in the 600F2 kit Dynojet included emulsion tubes that sort of shroud the
> needle in throat. I guess they sort of create like a mini venturi around the
> needle main interface and help atomize fuel better as it comes out of the
> main.
>   if your carbs have emulsion tubes might want to look at that, what little I
> remember is that they wear out from the rattling around of needle and the
> reult is less atomizing which i would think would result in leaner conditions.
> But dont quote me on that. I have never changed out emulsion tubes on 900SS.
> Just something to look for if it applies. Rich
> 
> Alec Moss <amoss at coastside.net> wrote:
>   I'll check with the propane routine. I seem to remember another way of
> checking that sounded safer, although I've done this before with my old
> (long gone) Triumphs. Do you remember what that was?
> 
> 
> Alec
> 
> 
> On 10/26/07 2:18 PM, "Rich Roberts" wrote:
> 
>> Could be an air leak. Rich
>> 
>> Alec Moss wrote: Thanks all. The bike has about 10,000
>> miles and, in neutral, when I roll on
>> the throttle a bit from idle, it rolls on smoothly but won't hold the
>> slightly higher rpm. It wants to race a bit. Maybe it's time. :-}
>> 
>> 
>> Alec
>> 
>> 
>> On 10/26/07 9:13 AM, "Bruce Bellm"
>> wrote:
>> 
>>> FWIW, I had them on my SS for 3 yrs. before I sold it. And, living in New
>>> England (albeit northeastern CT) it never failed to start using the drill
>>> you mentioned.
>>> 
>>> 
>>> 
>>>> Alec,
>>>> Having ridden both on a daily basis, from this statement I would stick
>>>> with the stock Mikuni carbs. The Keihins are a kick in the pants, but can
>>>> be a
>>>> little finicky upon start up (my ritual is 2-3 snaps of the throttle
>>>> before
>>>> start up) and they have no choke, so depending on your climate and riding
>>>> routine the stock carbs are sounding like the more practical choice.
>>>> Now to contradict that, if I only had one carb bike to ride, I would want
>>>> it
>>>> to have Keihins.
>>>> 
>>>> Rob
>>> 
>>> 
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> 
> 
> 
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> Our newest sponsor, MC Stands, has just opened its doors! It's a motorcycle
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