Bella Tune Up

by Joe Petrovec and Len Prokine

From the Jan and May 1960 issues of Car Life

Reproduced without permission

There are, as we have already explained (SCOOTER, October 1959), five good reasons for servicing your own scooter. Therefore, we shall not repeat ourselves but simply take up the subject for today, Zundapp's Bella 200. As we did with the Vespa tune-up, we chose the Bella as one of the best European designs and because it is typical of high-displacement, battery-ignition scooters. The following ten-step servicing of the Bella will, with minor changes, apply to all such machines of European make.

Our guides on our tour [of] the Bella's innards were Mr. Heinrich Rissman, fresh from the Zundapp works in Germany, and Walter van Schoenfeld, advertising director of Berliner Motors, who provided our test model. Purely for the record, the Bella tested features a 200 cc engine with battery ignition, key starter and a combination starter-generator.

The begin with, let's assume that our Bella has between 5,000 and 10,000 miles on it and, while it's running well, it seems to have lost some of its original pep. The first step in restoring it to its earlier lively condition is the removal of the rear casing. Before this can be done, it will be necessary to open the access door at the side, and disconnect the fuel line and the stop light plug. The fuel line is disengaged, using the starter key to pull the fuel tap outward, The stop light connection is broken simply be being pulled apart. This connection is color-matched, so there should be no problem in reassembly (Figure 1). The gas cap is then taken off and set aside. The four retaining screws can then be loosened and the casing removed.

Incidentally, there should be no problem with tools, since all necessary wrench sized are supplied in Zundapp's tool kip. The gas cap is then replaced on the tank for safety. This will not only keep the gas in the tank, but will keep any foreign matter out of it. Next, the gas tank retaining strap is undone. The fuel line is disconnected at the shut-off valve and the tank is lifted out front end first (Figure 2). Conversely when the tank is replaced, it will go in back end first. When all this is done, it will leave the Bella's engine completely accessible for service.

The first unit to be serviced is the carburetor. This is a necessary operation since the slightest amount of water in the carburetor jets will prevent starting. Remove the silencer by undoing the clamp. Disconnect the fuel and throttle lines (Figure 3) and remove the carburetor by loosening the strap closest to the cylinder. Turn the carburetor to the side, with the sediment bowl facing up and pull it free.

Cautious servicing of the carburetor involves only cleaning out the sediment bowl, but a thorough job consists of disassembling the entire unit and cleaning it in benzine or any similar solvent. This is not as formidable as it would appear at first and should present no real problem. Three points to keep in mind: Don't pierce the jets with a wire or probe to clean them. Blow through them. Keep lint away from the carburetor. And remember that there is an H on the carburetor body indicating the location of the main jet. The main jet has the larger opening. This will eliminate any possibility of error. When the carburetor has been cleaned, it is reassembled and set aside.

Next to be serviced is the cylinder. One of the beautiful features of the Bella is the ease with which this can be done. The spark plug lead is first disconnected and the plug removed and set aside. Using the wrench supplied, the four head bolts are broken loose, and the head is lifted off (Figure 4). It may be necessary to use an extension on the Tommy bar to break the bolts loose. The head gasket is of the permanent type and, if it is not broken or damaged, it can be re-used. With the piston at the top of its stroke, the carbon deposits may be removed by scraping with a dull knife. The scraping should be done gradually, stopping just short of exposing bright metal. This will prevent the removal of any meat from the piston itself (Figure 5). The head may also be cleaned gently, away from the engine, with a fine wire brush. When this is done, the cylinder is re-assembled, using only the Tommy bar for leverage.

Next, we come to the ignition. This, as we mentioned in the Vespa article, is a fairly critical area. It's also fairly durable and should be left alone as much ass possible. The points are checked through the aperture at the top of the ignition cover; if they gap at between .012 and .016 and are not seriously pitted, they should be left alone. If, however, they appear to need attention, the cover may be removed and the gap adjusted by loosening the set screw at the top and turning the adjustment screw below it (Figure 6). A tungsten file may also be run between the points gently to remove pitting, making sure that any and all debris is blown away. In Figure 7 we see one type of equipment used in the shop to correctly [set the timing].

When the ignition has been checked out, the next major step will be muffler service. As much as anything else, the proper running of the Bella depends on a clean muffler. According to Mr. Rissman, the nest and most straightforward way to clean the muffler is to dismount it from the frame, move it to a safe spot, pour some benzine into it and set it on fire. When it has burned itself out, the muffler should once again be clean and efficient. This process should be carried out at 10,000 mile intervals or less, if these intervals can be made to coincide with tune-ups.

The next step is the simplest. The spark plug is cleaned, regapped and replaced with a new washer. As usual, we recommend a new plug if there's any doubt at all about the old one. The plug gap is .027, but Mr. Rissman recommends .025 for easier starting, .028 for better running. Take your pick (Figure 8).

When the running gear has been reassembled, the scooter may be started and final adjustments made on the carburetor. First adjustment should be made to the idle nut (Figure 9). Second adjustment should be made to the mixture screw (Figure 10). Then the running should be balanced by returning again to the idle nut. By balancing between these two adjustments, a good idling and running setting should be obtainable.

Bella Ports

[Editor's Note: The following letter was published in the May 1960 issue of Car Life as a follow-up to the above article.]

You left a very, very important point out of Bella Tune-Up by Jow Petrovec and Len Prokine in December SCOOTER. The pictures and story are excellent, but you did not treat the two intake ports and the one exhaust port.

You can clean them by moving the piston to the bottom. Then you can see the ports, one on each side (intake) and one in the front (exhaust). After these are cleaned the tune-up will be complete.

I own a Bella 200 with 28,000 miles on it and it still runs very well. I have giver her four tune-ups, two tires, four plugs, one gas cable, two handle-bar grips and one set of rear brake linings. The points and condenser are still good, as they have not been replaced. I have owned five scooters and the Bella is the best. The others pooped out at about 25,000 miles.

Robert G. Sterner

Los Angeles, Calif.

Thanks for the valuable addition to out Bella Tune-Up. The ports are, in fact, a very crucial area of carbon accumulation which noticeably cut down performance. -Ed