Scuse me in advance for my bad english regarding the technical words. So, any
suggestion is welcome...
All photos from Pat, who races his triple in the European P2 unlimited class championship.
first part concerns the LAVERDA 1000 and 1200 tuning.
A special page for the 750 twins will follow.
Thanks to Patrick and Doug for their help.
power can be expected?
100 hp to the rear wheel (115/120 engine power) is a good average, regarding torque, reliability and reasonnable budget.
Consequently, to get a power really better than 100 hp to the wheel is an extremely hard and rigorous job, asking for hi-technology systems (ceramic coating for instance) or for very expensive and radical mods (monoblock cranks, ...)
So, we will aim in this page a basis of 100hp to the wheel, which can be possibly improved thanks to more radical solutions.
Camshafts: The available camshafts for the
Laverda triples can be improved, a lot of work is still to do on them (they
have been conceived 30 years ago!). Doug Home in Australia is working for
new cam designs, his work should allow good results soon.
Waiting for that, the cams available are the factory 4C and 7C cams, or the Axtell coming from the US.
Some engineers are triying to find more answers, like mixing 4C/7C, modifying the cam lobs or the timing with adjustable sprockets or at least different valve gaps.
For the 4C, which allow a better power at high rev without loosing the mid range torque, it seems that the good timing is obtained with closer gaps than preconized: 0.15 IN and 0.20 EX.
For the 7C, used on the fastest and straight tracks (good power at high revs but they kill the mid range) the gaps can be set at about 0.20 IN and 0.25 EX. As mentioned above, the 7C can broke the valve springs at very high revs and sometimes the pistons.
The Axtell cams are a good improvement for power and torque face to the factory cams, but the power drops off quickly over 7800 rpm. The Doug' work actually done in Australia should allow great results on all the power range, we are all waiting...
At least, the cams sprockets can be lightened by drilling them.
- Cam buckets: The small holes allowing to drain off the air when the buckets are lifted down by the cams must be slightly enlarged on the top of the bucket, in order that the oil film cannot be broken at high revs. A good improvement can be found by drilling 1mm from the top edge of the buckets liners, allowing oil to stay at this point.
We are speaking here about a tuning on an original Laverda engine basis, so we keep the assembled crankshaft basis.
These original cranks are very solid, tuning them is often limited to a careful balancing, to the alternator and starter freewheel removing and then to cut the conical end of the RHS of the crank to improve the ground clearance. However, it is possible to lighten and polish the crank for a better vivacity and security.
The Carillo rods are not a necessity except if the original rods are out of service. In this case, it will be necessary to fit new needle bearings.
They are often stiffened by welding near the engine fixing points and around the central crank bearings.
The oil case is often partitionned off to avoid the oil charge loss.
There is a very old debate beetwen those who use mineral monograde oil and those who use only 100% synthetic oils... Some pilots are very happy with the Castrol R40 as it works weel in the old engines and because synthetic oils avoid a good engine running-in and can made the clutch slipping.
Some others arguing that the synthetic oils are really a way to reduce the engine temperature and wear...
Each pilot has his own choice and some of them use other various solutions like, for instance, a dual lube system, Castrol R40 in the engine and multigrade in the clutch (a plate is then used to isolate the clutch from the engine oil), or synthetic oil in the engine and mineral multigrade in the clutch!...
The oil pump output must be improved, 2 ways for that: Fit a larger big capacity pump or modify the pump sprockets ratio.
If the engine is a 1200cc, fit a bigger oil cooler.
At least, dry lube system are more and more used.
The original Bosch ignition systems were already junk on road bikes, so in racing conditions... It is then necessary to get a serious and
reliable system. John Wilson (see the "improving" page of this site, IIS ignitions) has done a special racing ignition system, light and compact,
including different programmable advance curves.
The pilot can even order its own curves when he order the system. The ignition can be removed easily and quickly in case of problem (crash
or mechanical problem).
At least, this ignition can be delivered with a twin spark output in order to match with a twin spark cylinder head, which allow to improve the
power and to retard the initial advance of about 8°.
The spark plugs must be cold, NGK 9/10 EV or EGV or Bosch W3DPO (platinium projected electrode, same plugs as the Porsche 911Turbo).
A lot of solutions are used, from the very big 38 or 40 Dell'Orto to the 38 and even 41mm (!) in Japanese carbs (Keihin). However, the best results in race seem to be obtained with the 36mm Dell'Orto carbs.
Some pilots are even saying that the best results on various tracks are obtained with the 32mm Dell'Orto re-bored to 34mm, above all for the 1000cc engine.
Main jets around 175/180, pilot jets 65, 60/2 slides. Open bellmouths with 3 lenghts depending of the track, but some riders prefer big capacity home made air box, without filter, which calm the air input.
After a long use of 3 into 1 systems, it seems today that everyone wants to use 3-1-2 exhausts which allow a better power at top end.
Tube diameters are generarly 40mm, the collector is a large capacity system. The conical end shapes of the "silencers" have to be carefully
conceived to keep the homogeneity of the whole system.
Some new systems, including a sort of Exup, are experimented.
If allowed, an AvGas (aviation fuel) or a 105 leaded fuel is required.
Gearbox, secondary transmission:
No big changes to do. The main improvements to do are to chrome the selection drum and to reverse the gears selection (1rst gear up
and others down), the gearbox is easier in racing conditions. As for the transmission, fitting a narrower chain and sprockets(Zane style) is
a good improvement.
Remove the Triplex and replace it by 2 single chains, more solid and lighter, and remove the central teeth lines by turning them. The clutch
drum can be lightened too.
FRAME AND SUSPENSION TUNING
It is a special page done by Doug Home (Australia): -Click here-
WHEELS AND TYRES TUNING
It is a special page done by Doug Home (Australia): -Click here-