[Ducati] 900SS - Wits End
cedwards105
cedwards105 at cfl.rr.com
Sat Oct 27 10:42:00 EDT 2007
My DB2 ('93 900ss motor) came from the Bimota factory making 67rwhp on the
dyno at Battley Cycles, Rockville,MD.
A main jet change, leaner, and a return to the Ducati stock needles, versus
the Bimota engineered ones, had it up to 73rwhp.
A year or so later, not satisfied, I dropped the bike off with Greg Rammel,
after reading an article on Michael White's DB2 (California Dreaming) and
another from Peter Egan, stating he would only let Greg work on his bikes. I
had to twist Greg's arm to take my bike. My goal was to have a bike making
between 85-90rwhp.
I delivered it from Washington DC to just outside Detroit, 500 miles, in the
interior of my Dodge Town and Country Caravan. It would fit without the
tank/seat unit and fairing.
I picked it up about 3 months later, no rush on my part as Greg had it over
the winter.
The following was done to the bike;
944cc big bore kit, not a core swap
Pankl Ti rods
VeeTwo Cams
Falicon lightened, knife edged and balanced crank
39mm Keihin on ported stock long manifolds
CR Axtell Ported heads and modified valve stems for the VeeTwo cams
The bike ran great and had monstrous torque, but I was hugely disappointed
when it stopped dead at 80rwhp on the Battley's dyno again. We thought this
might be the Bimota exhaust design, so Battley's very kindly let me try a
stock 900ss exhaust, plus two or three different slip on's. The dyno results
were almost identical with all other exhausts.
Later that year, both Greg and I were at DOCC Grattan, Greg with another DB2
with all the same mods as mine with the exception of the Pankl rods, which
shouldn't made any difference in the HP area, just allow the motor to spin
up a little quicker.
Somebody had a dyno at the track so were put the two bikes on back to back.
Greg's bike made 86rwhp and mine made 80rwhp.
Frustrated, I let Tony Foster, who also had a DB2 making 90rwhp, with pretty
much the same mods as mine, running the Bimota stock exhaust, take the bike
back down to his shop in Daytona,FL. We though it might be the short versus
long intakes, but Greg's Db2 also had the long intakes and his was making 6
more Hp than mine.
After messing with the bike, Tony found, after doing a compression test, 3
of the 4 valves (CR Axtell's work) were not seating. After he fixed this and
put the short Malossi intakes with individual 41mm Keihin FCR's, degreed the
cams, it was up to 89rwhp. Life was good.
Shortly, thereafter I broke a rear belt at Grattan and dinged the valves,
piston and cam. Tony again took the bike back to FL and fixed everything,
but this time I had him put my stock cams in. One of the problems with the
Vee Two cams is the intake valve stem had to be lengthened by a couple of
mm, rather than bugger around anymore, that's when I decided to use my old
stock cams. The bike ended up at 86rwhp.
The bike now sits in track form at 352lbs full of fuel and is a blast to
ride, but not quite as much fun as my 1098S.
Both the 39mm on stock long intakes and the 41mm on short intakes work
really well. My only issue, between the two pairs, is the 39mm on stock
intakes had much better fit and placement than the 41mm on short intakes,
which require foam filters because of the placement of the battery box on
the DB2.
With the short intakes, the bike feels like it is making power all the way
to 9000rpm. The dyno confirmed it peaked at 8200rpm versus 7300rpm on the
long intakes.
Drivability of the Keihin FCR's versus the stock Mikunis is night and day.
My bike used to have a lag anytime I closed the throttle and then got back
on it. Mike Cecchini commented after riding my bike, with the FCR's, "This
feels like the bike has the most perfect fuel injection, I've never felt a
bike pull so cleanly and instantly with carb's".
I see it as my track bike when I decide the 1098 is a little too much,
probably when I'm about 60+ years old.
Hope this helps.
----- Original Message -----
From: "Rich Roberts" <bigredxrunner at yahoo.com>
To: "Ducati Owners Group" <ducati at ducati.net>
Sent: Saturday, October 27, 2007 10:02 AM
Subject: Re: [Ducati] 900SS - Wits End
> 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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> motorcycle
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> stands, or any kind of stand or lift, MC Stands tests, rates, and
> discounts
>everything they sell. Check them out!
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> Our newest sponsor, MC Stands, has just opened its doors! It's a
> motorcycle
> stand superstore. Every brand, every model, 95% in stock for immediate
> shipment. Whether front stands, rear stands, paddock stands, dirt bike
> stands, or any kind of stand or lift, MC Stands tests, rates, and
> discounts
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