Tuning
When it comes to tuning, our 2-valve engine kits have proven their quality for over a decade.
Our
main aim, however, is not to get the last possible horsepower from an
engine, but to create steadfast
affordable engines and a logical concept catering for the different
engine types.
Feel free to see
for yourself – we have a few tuned Guzzis here at all times for a
demonstration.
After all, a test drive is more convincing than figures and performance
diagrams.
Our setups are are done on our Dynojet dynamometer and on the road.
What
Kind of Tuning is Best for your Engine? Click here
1. Valve Drive
Thanks to the
rather “old fashioned” approach to the valve drive in 2-valve Guzzis we
get the chance
to improve a lot of things, not only as far as performance is
concerned, but also running characteristics
and lifespan. The common view that the original valve drive is meant to
last forever is, unfortunately, not
true. Pitting due to poor surface treatment and a lack of
lubrication, or burnt outlet valves including seat
rings prove the contrary. (The latter is due to the valve gap
slowly opening up.)
At the heart of any performance enhancement lies one of our five Valve
Drive Kits, which one depends
on engine type and requirements. A kit consists of an exchange
camshaft, 4 valve springs, 4 valve spring
collars and 4 cam followers, all made in Germany.
Kit D-8.1
Torque camshaft for significantly more power at low and medium revs as
well as up to 9 PS increase for the models
Le Mans 1-3 und all touring models with fuel injection or 36 mm
carburettors. It is also a simple method of getting rid
of the torque weakness in models with small bore cylinders, such as
V7-Sport, 750-S, 750-S3, V7-Special.
Performance
Diagram SP-3, Mille GT
Performance
Diagram California 1100, Jackal, Stone, EV
Kit K-7.7
Camshaft for all touring models with 30 mm carburettors. Makes the
engine more agile at all revs and pulls away more
powerfully from the very bottom right up to top speed. It also works
very well with those quiet production exhausts!
Kit D-7.2
Special torque camshaft for the models
LM4/LM-1000. It removes the torque gap at medium revs.
Kit L-7.9
Performance camshaft for the LM1-LM3, 1100
Sport and LM4/1000 with a 92 mm bore as well as for the
V11 Sport, but some piston work is necessary!
Performance
Diagram
Kit Race 9
Performance camshaft for the V11-Sport and 1100 Sport. Purely a sports
camshaft where performance at high revs is
paramount.
What
Valve Drive Kit is Best for your Engine? Click here
Quality
First:
Our camshafts are ground and plasma-nitrate coated in Germany, so
despite the increase in performance, the life span
of our valve drive is longer than that of the original.
The lubrication holes ensure pressure oil lubrication between lobe and
follower. This is another clear advantage over the
original, where the holes are located next to (!) the cam lobes.
Here the comparison: the original camshaft is on the left, HMB D-8.1 on
the right.
As you can clearly see in this image, the cam followers are lubricated
at the front of the ramp, thus reducing wear and
noise to a minimum.
Our camshafts are no copies, they are originals that have been
reground. This provides a better defined cam-lobe ramp.
The valves open without hammering and the valve drive remains
mechanically quiet and suffers very little wear.
In order to accommodate the slightly ball-shaped form of the cam
follower, the lobes are ground slightly asymmetrically.
This keeps the surface pressure on lobes and follower low and prevents
pitting.
Carefully selected valve spring kits matching the respective camshaft
complete the Kit. Each spring is individually
measured to keep tolerances low and to accommodate the engine type in
question. The steel valve spring collars
prevent damage to the collets and ensure a consistent spring distance.
Each spring kit is marked with its own distancing
requirements. (Please state engine type.)
Due to the valves quicker opening and their ability to rotate, burning
of the valves and seats can be effectively prevented.
As the thermal stress is now reduced, using unleaded fuel is no problem
and doesn’t require any further changes. You can
even use 91 octane petrol for some engine types.
After installing a Valve Drive Kit, the engine becomes more homogenous,
economical and above all agile, and if you consider
that the layout of the crankshaft, bearings, gearbox and end drive has
not changed in the current engines producing up to 92 PS,
it becomes clear that an engine optimisation makes sense for older
Guzzis, especially when it’s without decreasing their life
span. The riding fun definitely does not have to depend on the year of
manufacture!
Again: A test drive says more than words or diagrams …
2. Bore
Increase for Models up to 844 cc
Particularly for the 850 cc models, increasing the bore to 88 mm – as
is standard for the 1000 SP, Cali-2,
LM-4 etc – would be worthwhile. The cylinders are Nigusil coated and
experience shows that they last more
than 100,000 km. See also Complete Big Bore Kits
Although the old cylinders of the V7, 750-S, S3, 850-T, T3 were
chrome-plated, the chrome layer gradually
came off and caused damage to the entire engine. But the conversion to
Nigusil coated cylinders makes sense
for models with a standard 948 cc as well. The models 1000 SP,
V1000 - G5 and V1000 Convert had cylinders
with imprinted steel barrels which were worn after only a few
thousand kilometres. Heat conduction, too, is inferior
in these cylinders. We supply the cylinders for the 850 cc round
finned engines ready to be installed, so the engine
block does not require boring. And with a reasonable amount of
extra work, the bore of V7 models with 750 cc can
be increased as well. With a shortened 88 mm cylinder set, the cubic
capacity is 851 cc, whilst keeping the original
crankshaft. However, a few parts need modifying to achieve this.
Details under Contact us
In Italy, these cylinders are rated in several quality grades. We
exclusively supply first grade cylinder sets.
3.
Bore Increase for Models with 948 and 1064 cc
We can supply
coated cylinder sets with a bore of 92 mm (1038 cc) for square finned
engines starting from the
Le Mans 3. For the newer California and V11 models, we offer
cylinder sets with a bore of 95 mm. See also:
Complete Big Bore Kits
These cylinders
are tailor-made for each engine type and ensure a significantly higher
torque from the 1134 cc
capacity. The cylinder material (including Mahle pistons) is made in
Germany and guarantees maximum operating
safety. Performance increases in the range of 10 PS and 10 Nm are
possible, depending on the model – even
higher when using one of our Valve Drive Kits. Due to the changed mass
ratio, balancing the crankshaft is essential,
as is work to the combustion chamber. For an engine performance over
100 PS, we recommend Carrillo con-rods
due to their better stability. Feel free to call us if you require
advice.Contact
us
4. Reworking the
Combustion Chamber
To optimise the
squish-band, we have to shorten the cylinders. This is the only way to
ensure a thorough mixture of fuel
and air. We then measure the volumes of the combustion chambers
to achieve the correct compression ratio, balanced
for both cylinders. This also compensates for tolerance
differences in the components and ensures that the engine runs
more quietly. It also reduces emissions and enhances fuel consumption.
In the sport engines with a bore of 92 mm
(1100 Sport, V11 Sport) the squish-band is machined at an angle for
emission reasons, but this leads to a noticeable
torque loss at medium revs. Here, we can compensate for a lot by
reworking the combustion chamber. Depending on
camshaft type, the combustion chamber is reworked with regard to valve
play and the valve pockets.
If larger carburettors are used,
the inlet channels are reworked accordingly. If desired, the cylinder
heads can be converted
to twin plugs. This is especially recommended for big bores and high
piston domes and has a beneficial effect again on
fuel consumption and emissions.
5. Twin
Plug Conversion
A twin plug conversion is less of a tuning measure, but rather an
optimisation. The long spark travel in the combustion
chamber requires high initial ignition values, which in turn carries a
risk of self-ignition (ringing). By igniting the mixture
from two sides, the chances of pre-ignition can be reduced
considerably. Combustion becomes more even and effective,
starting behaviour and torque are enhanced. Twin plugs generally make
sense for large bores and high piston domes.
We use 10 mm spark plugs and a special stay bolt. This way, the seat of
the rear stay bolt does not require reducing
so there is no danger of the cylinder head distorting. The conversion
kit contains the special stay bolts, spark plugs
and spark plug spanner. We change the ignition advance characteristics
(depending on the engine type) regardless
of whether the vehicle is fitted with an interrupt ignition or an
electronic ignition system. The software of the models
California EV and V11-Sport can also be modified accordingly.
6.
Balancing
We will balance the optimised engines on the dynom and on road using a lambda test
device. Test bed measurements
alone are useless (although offered again and again) as they do not
factor in the airflow. Only on the road
can realistic conditions be achieved. Starting with jet sizes drawn
from past experience, we conduct several
measuring rides until the best possible equipment has been found. Only
then are we in possession of all the
relevant factors (incl. intake and exhaust system) to ensure the
mixture is exactly right.
7. Decreasing
the Centrifugal Mass
As
the production clutch on the pre-1993 models is very heavy, decreasing
the centrifugal mass is another
possibility. We decrease the weight of the flywheel and the starter
ring gear and balance the components.
After an initial decreasing, the flywheel weighs only 1.65 kg, the ring
gear 1.35 kg. The reaction of the engine
improves, whilst the gearbox is protected. The production clutch
with newer fine-tooth clutch boss has proved
steadfast in tuned engines with over 100 PS as well, which cannot be
said of many single-disc clutches on the
market – see Fundstücke (Amazing Finds)
Therefore, we believe that decreasing the centrifugal mass of the
original clutch is a sensible and inexpensive
alternative.
