Ducati Monster Forum

Hi guys, im idling around 900rpm and it stalls on idle a bit.
I am wondering if the air bleed screws adjust anything else apart from idle?
Its to late anyway, ive adjusted both equally and am now idling around 1100rpm, just wondering if ive buggered anything else up?

On another note, ive filed down my cam for my Rizoma Grips and it is no longer catching, i just have about 4mm of play in my throttle which feels like a bit to much.

NEXT EDITION: A detailed run through on how ive buggered up my throttle by trying to adjust some of the play out of it :)

adjusting the air bleed screws will raise/lower your idle but because it adjusts the mixture too it also affects rideability, it may be more/less snatchy just off a closed throttle, which by the way will become more pronounced and annoying with too tight a throttle cable. you can adjust the throttle cable easily with the screw lock at the twist grip cam but leave _some_ slack, usually 1mm or enough for you to feel it if you fiddle with it, that should be right and you won't notice it while riding.

paul.

worth noting too, that 900rpm is very low for that bike, makes me wonder how the rest of the bike is set up, saw your dyno run and it's on the low side, although they're only numbers and dynos are all different, just wondering if it's had a full service and tune since you got it?

Yep had a full service and tune. Everything was balanced and set before the Dyno and Power Commander install.

Its still back firing a little on decel from the 2-5k rpm range

Yes Andrew, backing out your air bleed screws to increase idle speed is likely to cause more farting and popping on the overun...its a priority thing. 

Cheers

the S4R has those stupid little headers with the fibre gaskets, same as the ST3, but they are notorious for leaking, mine leaked all the time, and the front header was cracked at the welds too, so don't be surprised if it always pops on the overrun, mine backfired badly until i fixed it.

paul.

I've had a good look over the headers and no cracks and mike replaced the gaskets and sealed it up recently.... It has about 36k I'm on it.... My next guess is a ring might be going though it never did it when the cat was on.

i doubt the rings are wearing, it doesn't matter how well you seal that exhaust it will always leak somewhere! the std stubby headers are garbage, they're made from pressed steel and the std header gasket is too thin for them, there's just not enough material to crush consistently across a wonky surface (the header, not the cylinder head exhaust face). you're up against it i'm afraid, the genuine gasket is too thin, the header is good for scrap and the slip joint fibre crush gasket usually fails at the first sight of water. I put 996 superbike headers on mine with custom thick exhaust manifold gaskets and that did away with the slip joint gasket. works a charm, add to that the larger diameter of the joint, 10mm larger diameter, easy! and i'm getting more power and more range, lots more range. It's a worthwhile mod if you're handy with a TIG or are friendly with someone who is.

paul.

this is from my s4 manual , i am guessing it would be similar for yours

worth a read

THROTTLE BODY
ADJUSTMENT
The throttle body is critical
component in engine power
management and is responsible for
performance and exhaust emission
control.
During production the throttle body
assembly is adjusted and set using
data from extensive testing. Each
part of the throttle body assembly is
an integral part of the injectionignition
system and must work in
complete harmony with all the other
parts of the system.
The throttle body should therefore
be seen as a whole and we strongly
advise you to treat it as such. This
section describes the procedure for
adjusting the throttle body as a
system.
This section describes the following
operations:
❍ Positioning the throttle position
sensor
❍ Balancing the air flow
❍ Adjusting the idling mixture
The idling mixture strength is an
engine operating parameter subject
to strict international environmental
protection legislation. This
legislation tends towards a lean
mixture (with CO at 1.5%) while
optimum vehicle performance
tends towards full-load mixtures
with CO values between 3% and
6%.
As in many cases this motorcycle is
used for racing, the last value will be
considered.
For this operation you will require
the following instruments:
❍ “MATHESIS” tester, part no.
88765.1236 and relevant manual.
❍ Mercury column vacuometer.
❍ CO tester.


Adjusting the idling mixture
❍ Connect the Mathesis tester
power cable (1) port (A) to the
diagnosis outlet (2) under the seat.
Enter the “Self-Diagnosis” menu
and select the bike model.
If the procedure has been carried
out successfully, the tester makes a
connection with the engine control
unit.
❍ Select the “Parameter Reading”
function.
❍ Select the “Throttle position
sensor check” function.
❍ Turn the adjuster (3) of the
MASTER throttle in order to reach
throttle and voltage values of 2.3°
equal to 403 mV.
▲ If the throttle control cable has
been removed, install it again into
the pulley in order to activate the
control and then adjust the travel
(refer to “Adjusting the throttle and
choke cables” under this section).
❍ Turn the adjuster (3) until reading
the throttle angle and voltage values
previously obtained.
Adjusting the throttle set
screw (vertical cylinder)
❍ Disconnect throttle position
sensor from bike wiring and
connect it directly to the Mathesis
tester using the throttle position
sensor adaptor cable (4, part No.
514.1.032.1A).
❍ Enter the “Auxiliary” function,
“Throttle position sensor” and then
“Throttle position sensor
adjustment”.
❍ Note the reading appearing on
the tester.
❍ Slowly turn the screw (5) of the
vertical cylinder throttle in order to
slightly change the voltage.
❍ Turn screw (5) of the vertical
cylinder throttle again until reading
the value you have noted on the
Mathesis tester.
Balancing the air flows
❍ Remove the screw on the
vacuometer connector hole and
connect the vacuometer to the
intake manifolds.
❍ Fully tighten and close the bypass
screws (6).
❍ Refit those parts you have
removed, start the engine and run it
slightly fast.
❍ Balance the vacuum in the intake
manifolds by turning the nut (7) on
the throttle linkage rod.

Adjusting the CO rate
❍ Loosen the by-pass screws (1) on
each cylinder of about one turn until
reaching an idling speed (1,000-
1,100 rpm) with balanced air flows.
❍ Connect the CO tester to the
outlets on the exhaust pipes with
unions part No. 88713.1010 to read
the exhaust gas composition.
❍ Make sure that engine
temperature is above 65 °C.
❍ Take readings on both horizontal
and vertical cylinders.
The CO rate difference between the
two cylinders should not exceed
0.5 % and the CO rate should
anyway be within 3 and 6%.
❍ If the difference between the two
cylinders is big – such as 1% - adjust
the CO rate turning the by-pass
screws (1) one at a time: screw the
by-pass screw of the “leaner”
cylinder or slightly loosen the screw
of the “richest” one.
❍ If the difference between the two
cylinders is small, i.e. below 0.5%
but the CO is lower than 3% or
above 6%, use the control unit
trimmer to adjust the CO rate on
both cylinders at the same time.
❍ To operate on the trimmer it is
necessary to use the Mathesis
tester.
Enter the "Self-diagnosis" function.
❍ Enter the “Active diagnosis”
function and then “Trimmer
adjustment”.

Andrew.......did you take all of the above in mate...??????      ;D  I tried too but i am on my third wine here.....Hic........... [wine]  Maybe a ride tomorrow to Meadowbank or Clyde is in order....Hope you get it sorted

Brian