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Motorcycle "Jupiter IZH-4": specifications, photos and reviews

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Motorcycle "Jupiter IZH-4": specifications, photos and reviews
Motorcycle "Jupiter IZH-4": specifications, photos and reviews

Probably, the brainchild of the Soviet auto and motorcycle industry will travel the roads of modern CIS countries for a long time to come. It will be about the motorcycle "IZH Jupiter-4".


The IZH Jupiter-4 road bike was produced by the Izhevsk machine-building plant from 1980 to 1985. In the production race of machine-building plants, Izhmash decided to increase the maximum speed of the motorcycle by upgrading the engine. Not surprisingly, the production of the Czech Jawa did not suffer any losses.

jupiter izh 4
jupiter izh 4

At that time Jawa was Izhey's main competitor. The elegant Czech motorcycle surpassed the "Jupiter" in a more thoughtful design. Czech engineers have created a more frisky, economical and, most importantly, reliable two-wheeled transport. Despite this, the domestic "IZH" was in considerable demand within the country. Over the five years of production, the Izhmash plant has produced and sold more than a million copies of IZH Jupiter-4 and IZH Jupiter-4k. The latter is distinguished by the presence of a side trailer (carriage). After 1985, a new series of domestic motorcycles "IZH Jupiter-5" was launched into production.

Specifications, recommendations

Consider the qualitative data of the motorcycle "IZH Jupiter-4". Its characteristic is as follows:

  • engine power - 28 hp p.;
  • top speed - 130 km/h;
  • weight - 160 kilograms (with equipment);
  • maximum engine speed - 7800 rpm;
  • ground clearance - 130mm;
  • Gearbox 4-speed, semi-automatic;
  • oil-bath multi-plate clutch system;
  • fuel type - air-gasoline mixture (Ai - 76, Ai - 80 together with oil);
  • two-cylinder carbureted two-stroke.
izh jupiter 4
izh jupiter 4

Since the ignition of "IZH Jupiter-4" has a cam, it is important to set it up securely and sometimes inspect it. The process of setting the moment of spark supply is described below. It is important that the alternator armature is installed evenly, and the bolt with which it is attracted to the crankshaft is tightened tightly.

From time to time it doesn't hurt to inspect the ignition elements. Soviet engineers did not provide for the machine to operate smoothly in the mode of water or humidity. Therefore, if there is a problem with the spark, you need to inspect the ignition contacts for oxidation.

Similar procedures do not hurt to carry out with other electrical systems and contacts.

The difference between "Jupiter IZH-4" and its predecessor - "IZH Yu3"

Actually, it is considered the most successful and reliable among the generation of "Jupiters" "fourth". It differs from its predecessor "IZH Jupiter-3" in a more powerful power unit (the power of "IZHJupiter-4 "is 28 horsepower, while Jupiter-3 produces only 25). The engineers of the Izhmash plant managed to increase engine power due to the new design of the cylinders. In the new cylinders, the designers provided for wider purge windows. For due to this, the maximum crankshaft speed increased (7800 rpm).

motorcycle izh jupiter 4
motorcycle izh jupiter 4

But, unfortunately, in the pursuit of money, the plant missed the issue of quality and reliability of the design. Years later, IZH Jupiter-4 showed its weaknesses. Namely, the design of the cylinders did not provide for higher strength and reliability. The engine resource has significantly decreased due to the increase in purge windows.

In addition to the modernization of the cylinder-piston group, Izhmash specialists provided modern 12-volt electrical equipment on the new Jupiter model. This upgrade gave "IZH Yu-4" a brighter light and a more powerful ignition spark compared to 6-volt previous models.

About shortcomings

It is worth noting that among the owners of IZH motorcycles, the Jupiter IZH-4 model is not very popular. Experienced users claim that the fourth "Jupiter" is the most unfortunate model from the entire model range of IZH motorcycles. In addition to the fact that the strength of the high-speed engine leaves much to be desired, "Jupiter-4" has such "diseases" and disadvantages:

  • constant oil leakage from the crankcase;
  • "ringing" fingers after a short period of use;
  • small resourcePPC;
  • constant problems with the ignition system;
  • high fuel consumption;
  • lack of systems for monitoring the fuel level, engine temperature and oil level in the crankcase;
  • outdated design;
  • lack of knowledge in the operation and repair of this motorcycle can lead to significant material costs for the repair of the unit and / or treatment of the biker.

Most of the owners of Soviet motorcycles are sure of the above. Particular attention must be paid to the ignition system. In fact, the process of setting the ignition timing does not require phenomenal skills or special knowledge.


Reviews "Jupiter IZH-4" has both positive and negative. Some of the owners of the bike are sure that if you take care of the equipment, do a technical inspection and repair in a timely manner, the result will not be long in coming. By purchasing a motorcycle, you can have virtually zero knowledge regarding repair and operation. The main thing is that "Jupiter IZH-4" should be bought either in good condition, or its full repair should be made. Then a lot of problems and "diseases" of the motorcycle will not disturb the driver.

izh jupiter 4 characteristic
izh jupiter 4 characteristic

Other owners of this motorcycle refer to the high engine power and excellent acceleration performance as positive aspects. If you make a few changes to the design, "IZH Jupiter-4" easily acquires a modern attractive look.

Complaints mainly concern the unstable relay-regulatorvoltage, problems with the ignition system and rapid wear of engine components.

Ignition setting "IZH Yu-4"

To correctly adjust the ignition timing, you must adhere to the following points:

  1. Remove spark plugs from both cylinders.
  2. Turn the crankshaft by the generator armature bolt (key 11 fits) until the breaker contacts open to the maximum, which is based on 6.
  3. Loosen bolt 5 and rotate 4, setting the gap to the thickness of the razor blade (or 0.4-0.6 mm, if there are accurate measurements
  4. ignition izh jupiter 4
    ignition izh jupiter 4


  5. Fix bolt 5, do the same procedure with the top contact, i.e. the left cylinder.
  6. Use a stroke gauge. If not, use a thick, smooth-surfaced rod that will fit into the spark plug hole.
  7. Rotate the crankshaft until the right piston reaches top dead center, lower it 2.2-2.6 mm lower by turning the crankshaft counterclockwise.
  8. Unscrew bolts 2, 3, 7, set the distance between the lower contacts 0.2-0.6 mm or the thickness of the blade by turning the eccentric 4.
  9. Perform a similar procedure with the left cylinder, the ignition of which determines the top contact.

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