The Munch Bunch

THE MUNCH BUNCH

Engines, Engines Everywhere...and Indians, Too!

BRUCE COX

GERMAN ENGINEER Friedel Munch-builder of the four-cylinder Munch Mammoth and, with American ex-publisher, Floyd Clymer, reincarnator of the American Indian-is bidding for international racing success.

Munch has built a twin-cylinder dohc 500-cc engine that he hopes will be battling it out on the European grand prix circuits next season. There is also an sohc Twin lurking in the wings that could bring the name Indian back on to the AMA National scene!

Munch had both engines on display at the Cologne Motorcycle Show in October, 1968, and is planning a thorough testing program throughout the winter.

A twin-loop cradle frame already has been designed to house the Grand Prix engine—though Munch may also seek the advice of established frame specialists—and he will use forks and hubs of his own manufacture.

The 500-cc Grand Prix Twin has a 71.5-mm bore and a stroke of 62 mm. Its dohc system is driven by a chain which runs up through the center of the engine, and there are four valves per cylinder, with a central spark plug.

In-unit with the engine is a five-speed gearbox. Running beneath the complete unit is a deeply-finned sump that contains 6 pt. of engine oil. Gearbox and engine oil are separate—unlike the new Indian single-cam engines that Munch also has designed.

The crankcase is cast in magnesium, and the heads and barrels are of a new high-strength, ultra-lightweight aluminum.

Primary drive is by straight-cut gears, then through the six-plate, dry clutch.

Development on the cycle parts is keeping pace with that of the engine.

Munch already has built his own telescopic forks, with 148 cc of damping oil in each leg and a travel of 5.9 in. He also will use one of his own massive 10-in. magnesium front brakes with Ferodo linings on the 2-in. wide shoes.

The complete machine will be ready for race testing early this year, possibly with a top-line English rider in the saddle.

Munch has tried several types of carburetor, including Amals and Webers, and with choke sizes ranging from 35 mm to 40 mm.

Results are so far consistent, with a power output of over 60 bhp at 10,000 rpm when initial development experiments have been completed.

Should the engine prove to be a success, Munch will offer a limited number for sale to international class racers.

Munch’s other project-the sohc Twin engines that will power the bulk of the new Indian range—could mean a return to AMA racing for the marque. No plans have yet been made for an Indian comeback, but the powerplant, in 500-cc form, certainly would be eligible, and Munch already has designed a racing kit for it. The engine has been completely designed and built at Munch’s plant in West Germany, though in some respects it resembles the Horex Imperator, an engine that went out of production in Germany some years ago.

Obviously trying to cater for all large displacement bike enthusiasts, the engine is available in displacements of 450 cc, 500 cc, 600 cc and 750 cc.

In the three smaller versions, the camshaft is driven by a chain through the center of the engine and the twopiece crankshaft runs on four roller bearings—two in the center and one on each side.

The crank is splined together for ease of maintenance, but a useful side effect of this is that the engine firing order can be either 180 or 360 degrees.

Primary drive is by bevel gears. The integral sump holds 5 pt. of oil to serve both engine and gearbox.

All models of the bike are well oversquare, with the 600 being typical at a 76-mm bore and 66-mm stroke.

The 450-, 500and 600-cc engines already have been extensively dynamometer tested and are returning figures of 42, 50 and 56 bhp, respectively!

Munch is still busy on the 750, as the bores on this are too big to allow the camshaft drive chain to run up between the cylinders. The drive chain on the 750 will run up the outside of the engine. Though this powerplant is in development stages, Munch is confident it will produce approximately 65 bhp when completed.

All these horsepower figures are for entirely standard versions of each engine. Kits designed by Munch to raise the power for racing include a variety of cams, high compression pistons and stronger valve springs.

On display at Cologne were complete machines with the Munch engines housed in special frames built for Indian by the Italian Ital-jet firm.

In similar frames were both standard and Thruxton racing Velocette 500-cc engines. These models are the least costly in the new Indian line.

Other projects from Clymer, Munch or Indian—choose any one of three—are the rejuvenated 45-cu. in. Scout V-twin sidevalve and the latest Munch Mammoth with its four-cylinder powerplant from the NSU 1100-cc car, developing over 90 bhp! This power has been reached by fitting the special cylinder heads from the NSU TTS 1200-cc sports sedan to the 1100-cc engine.

Also in line for future production is a 65-cu. in. Scout, another V-twin sidevalve in a modern frame.

V-twin sidevalves, twin-cam racers and four single-cam roadsters-any prizes for versatihty should go to Friedel Munch.