Archive for category: Generation XI (Vespa ET3)

Out of more than 120 scooters, the most beautiful scooters were awarded in 17 categories.

A great success for us, the SCK-Racer Generation XI is “BEST SMALLFRAME"

That had to work too!

... because whoever looks back on a successful 20-year existence this year ...

Exactly this morning at 10:00 our frame comes rolled into the yard - finally!

Everyone is excited to see what the good piece looks like, so first unpack and admire!

Unfortunately there is not too much time to look at every detail in peace, because the CS in Ried is approaching with great strides and time is of the essence.

So the step rails are attached directly - we use hammer rivets for this, as it should be.

The rivets are attached with a hammer drone. The waffle pattern creates the typical Piaggio character.

We had the strips and end pieces coated with black powder, because in the short time nobody was to be found who could "just" provide the same with a beautiful gold plating.

In my opinion, a very successful stopgap solution.

After moving in the bearings followed by the harness and the Bouwdenzug.

Last but not least, we get the engine from the P4 and install the rear disc brake system, which had to give way to the brake cable actuated drum for the test stand due to time constraints.

Our racer is cuddled up carefully - lights off - good night and see you tomorrow.

At Pfeil Design in Austria, we are working hard on our racer so that the frame and all attachments are with us on Tuesday.
Then you have to go full throttle for 2 days so that the bullet is ready in time for the custom show in Ried and you can see it on site.
In the meantime we are making the final preparations so that the engine may go to the test bench on Monday :-)
So let's start with the last little things ...
The Grand Sport oil drain plugs are equipped with a magnet, which holds the resulting metallic abrasion, which reduces wear.
Unfortunately, there are no bores on the engine housing for the wire securing of the oil screws, which is mandatory on race tracks. In order to get a visually pleasing solution, Dennis makes a small retaining plate “just quickly”.

Quickly twirl the wire on it ...

If screws are secured with wire, one should always make sure that the wire is guided around the screw in such a way that the screw always has to "pull" on the wire if it wanted to loosen and the direction of pull of the safety wire does not favor loosening the screw.

Other important little things are added ...

Kickstarter and the bracket for the Clutch.

Here, too, something has to be reworked ...

Our engine also has to be ventilated, unfortunately the really large carburettors were sold out, so we are content with one Keihin, 38 Airstriker.

The Falc intake manifold that we use comes with its stuffer. The Polini seal for the membrane must therefore be adapted.

Fortunately, Polini supplies a suitable Falc stencil directly :-)

At the bottom left in the picture you can see the foot of the camera tripod.
That happens when the “photo studio” is actually the welding table ...

... further in the text.

Seal fits, mount suction.

Now that the suction device is installed, let's turn to the cylinder hood.

Direct suction, air-cooled Smallframe Cylinders have the disadvantage that the hot air flow is directed through the shape of the original cylinder hood directly onto the intake manifold.

This has 2 main effects:

1. The suction device becomes disproportionately warm, which in turn reduces its performance.

2. The hot air is blocked by the intake manifold, which can cause thermal problems.

So we have to edit the cylinder hood accordingly to ensure that the intake port remains as cool as possible and that the cooling air is still safely discharged.

The hood is first roughly trimmed and then brought back into shape with a heat gun. The hood has to be adapted to the cylinder again and again.

As soon as the shape fits, the holes for the cooling air are made.

When milling you should make absolutely sure that the milling cutter does not get too hot. Because the plastic cannot absorb the heat generated to the same extent as metal.

This is how it should work.

The last little thing for today is the cable box.

Before we continue with the ignition as promised today, there is first good news from Austria and on the subject of shock absorbers.

Finally the dampers for our project have arrived, of course changed visually to match our racer compared to the later series.

At the “Pfeili” work continues ...

But it is much better that the finished frame should be with us by Tuesday next week.

That would mean a full 2 ​​days (we want to leave on Friday at 6:00 am!) For the assembly.

Now the ignition continues.

The base plate is screwed onto the motor housing in the Vespatronic basic setting.

Then we put the pole wheel on.

It is characteristic of Vespatronic that the normal Vespa flywheel nut can usually only be fitted with a nut that is turned off in diameter.

Or you can use a mother from the Piaggio automatic range.
Within the Vario nut for the large Piaggio engines, the wrench size is reduced to 18 mm.
In addition, the nut comes directly with the fuse pressed on.

A nut SW18 fits unchanged into the Vespatronic pole wheel.

The pole wheel is tightened to 65Nm.

In order to check the ignition timing later and to make understandable changes, we still have to attach ignition markings.

We use the reversal measurement for this.
We apply the first marking with a piston stopper, which is to serve as a defined stop.

Mark 1

then over the UT again to the stop. Here you transfer the marking from the pole wheel back to the motor housing.

The OT is between these two markings, the easiest way to mark it with a compass.

Now that we know the OT, the desired ignition markings can be applied counterclockwise.

To do this, you have to remove the circumference on the motor housing and divide it through 360 °.
The result then corresponds to the value in mm for 1 °. In our case we come to 1,36mm / 1 °.

The Vespatronic adjusts the ignition point with increasing engine speed by 8 ° in the direction of retardation, i.e. less degrees from TDC.

So if we want an ignition value of 17 ° before OT at our engine speed, the ignition must be set to 25 ° in the basic setting. In order to be able to control this, we put a mark at 25 ° BCE. With our determined value, we come to a radian dimension of 34mm, which we remove counterclockwise from the TDC.

A steel or a piece of tape measure is best.

Setting and labeling.

As soon as the engine is running, the setting can be checked with a strobe light.

Briefly about the CDI, the Vespatronic CDI is notorious for getting rid of its plug connections every now and then.
So that it doesn't get that far in the first place, we simply leave the plugs off at this point and solder the cables.
Polini, for example, offers one Similar ignition system on whose CDI the cables are already soldered on.

The soldered cables are still with shrink tubing Protected against vibration death before being together in one Bow pipe disappear.

So much for today….

12 days left until the custom show in Ried….

We have now defined cylinder outlet and overflow angles and processed the cylinder accordingly.

The next step is to check the crush dimension, the distance from the piston to the cylinder head.
Polini gives for the Evolution Direkt a recommendation from 1,00mm.
To get an idea of ​​whether and, if so, how much the cylinder needs to be milled, we first measure the piston residue.

Here we come to 1,2mm. Plus the thickness of the cylinder head gasket of 0,5mm, we come to a crush dimension of 1,7mm. So our Polini cylinder has to be 0,7mm shorter.

In order to be able to machine the cylinder, it is prepared for a clamping device.

Here with the jig for processing.

So prepared, it goes to the milling machine - briefly measure it

and then the chips fly ...

Done!

Now comes the moment when it turns out that we have measured everything correctly and that the hogger has done a good job.

We use tin solder to determine the new squeeze dimension. As with measuring, it is important that all measurements are taken parallel to the piston pin. Otherwise the piston could tilt due to its play in the cylinder and thus falsify the dimension.

And?!

Ah, everything went well - precision landing!

Before we start assembling the engine, there are other little things to do.

For example, the prime mover still needs to be prepared.
The GP-One clutch is mounted with its own so-called rep kit, i.e. the cover disks under which the primary springs do their work as shock absorbers.

So first we have to free the primary from the simple cover disks. This task is done quickly with an angle grinder.

Since in our case the clutch has to be assembled in the engine, we mount the rear cover disc of the clutch on the large primary gear and insert the springs.

We grind the cone of the auxiliary shaft and the clutch basket so that the power that our projectile hopefully develops sufficiently can also be transferred to the gearbox Valve grinding paste each other. This is to prevent the clutch basket from starting to work on the small cone of the auxiliary shaft due to minimal angular errors.

Grinding in is repeated until a uniform contact pattern is obtained on the auxiliary shaft and the basket.
Also the fan wheel cone of the Vespatronic we grind in like that. Especially when it comes to the flywheel mass of the ignition system, it is important that the cones fit together really well. Due to the high speeds compared to the clutch, high-performance motors can otherwise quickly cause vibrations and thus damage.

Now that all the preparatory work relating to the motor has been done, it is now time to insert the ball bearings and assemble the housing.

With a normal cast aluminum motor housing, a hot air blower or a small blowtorch is usually sufficient to heat the housing to approx. 80 ° and allow the cooled bearings to fall into their seats.

However, the CNC housing is so massive that it would be quite time-consuming to bring the housing to the appropriate temperature with a blowtorch.

So we just put the case in the oven.
Unfortunately, this sometimes leads to irritations when preparing for lunch.
But today: engine before potato casserole!

Usually you would use the ball bearings Cooler spray cool quickly so that they fall so shrunken into their seat. But with the current outside temperatures of around -7 °, it is enough to simply put the ball bearings in front of the door.

When installing the Primary bearing 16005, it is noticeable that the seat has some play, as is the case with the Piaggio housings. In order to avoid that the bearing starts to move back and forth in its seat due to the transmitted torque to the gearbox and the actuation of the clutch, we compensate for the play Shims .

With this bearing, it is important that there is no shim washer on the auxiliary shaft side, as the oil collecting plate is mounted here, which in turn supplies the bearing with the essential lubrication.

As long as the ball bearings are still warm through the housing, the crankshaft, main shaft and, as shown above, the primary drive can be used very well.

Shift rocker, Kichstarter segment and shaft seals follow.

Before assembling, we simply glue the paper seal to one half of the housing with grease.

The shaft seal seat of the crankshaft is also given a little grease so that the sealing lip of the shaft seal does not turn inside out and the spring pops out during assembly.

When assembling the housing halves, it is sometimes necessary to move the gearbox so that the gear wheels of the main and auxiliary shafts find each other. Since our disc brake hub is on the way to be galvanized, we simply take the pattern for the main shaft toothing.

As soon as the housing halves have come together and the housing bolts are tightened, the piston and cylinder can be assembled.

Before the piston disappears into its cylinder for a long time, it and the lower connecting rod bearing of the crankshaft get a drop Motul with on the way.

The cylinder only comes with without a base seal Sealant assembled.

After the cylinder has been installed, the cylinder head is then tightened step by step and crosswise with the torque wrench.

That's how far we are today ...