Restoration of the Ural IMZ 8.103-10 motorcycle

It has become popular, at the same time, and expensive to have a high-quality and powerful motorcycle from well-known global suppliers. Ural motorcycle is not far from foreign motorcycles; if you look at the prices, you’ll go crazy, the price is like a car. Therefore, new Urals are rarely bought on the domestic market, although they are supplied to the Armed Forces of the Russian Federation and other law enforcement agencies, but abroad they are in, albeit small, but definite demand. Most of the motorcycles available to the population are outdated models produced in the last century; prices in those days were affordable. Speaking about the Ural motorcycle, the first thing that comes to mind is what kind of IMZ-8.103-10 (IMZ-8.103-30, M-67-36) engine it has, are there any shortcomings and weak points because it is the qualities and characteristics of the engine that underlie the characteristics motorcycle Ural.

Weaknesses of the IMZ-8.103-10 (IMZ-8.103-30, M-67-36) engine of the Ural motorcycle

• Foot starter (kickstarter);
• Gas and clutch cables;
• Generator;
• Carburetors;
• Cylinder heads;
• Reverse gear (gearbox).

More details about the weak points of the motor...

Foot starter (kickstarter)

The foot starter of the IMZ-8.103-10 engine is a weak point due to the slippage of the pawl. The malfunction is eliminated after dismantling the gearbox and disassembling it with rearranging the pawl with the other side or replacing it. I have an assumption that the metal of the dog is of low hardness. On the other hand, if the pawl is made harder, the gear will fail. You need to choose the golden mean.

Throttle and clutch cables

The clutch control and fuel supply cables are a weak point due to their short service life. To put it simply, they tear, and before that they stretch, which makes it necessary to adjust the timing of the supply of the fuel mixture, as well as the clutch.

Generator

The generator does not run for a long time.

Carburetors

Gasoline gets into the floats, after which the cylinder is filled with gasoline. In addition, carburetors are not matched to these engines; half of the fuel goes to waste, which is not economical. It would be nice if the engine had one carburetor instead of two.

Cylinder heads

Do not overtighten the spark plug heads; the threads break off quite easily. You cannot overheat the engine, the result will be clearly visible on the heads, the studs are pulled out, leading to the landing plane of the heads. If you are unable to avoid breaking the spark plug thread, contact a familiar turner; he will be happy to repair it and install a steel threaded bushing for a modest fee. I can recommend the same for wear of valve seats and chamfers. It is much cheaper to repair heads than to buy new ones; a good turner can do this in no time.

Reverse gear (gearbox)

The reverse gear does not work for a long time due to the rapid wear of the reverse gear in the gearbox.

Disadvantages of the IMZ-8.103-10 (IMZ-8.103-30, M-67-36) engine of the Ural motorcycle

• Small resource;
• Starting is difficult or does not start at all;
• In hot weather, it gets very hot in low gears;
• Interruptions in the operation of the cylinders;
• Knocking;
• High fuel consumption;
• There are a sufficient number of cases of inaccuracy in the manufacture of the engine crankcase at the cylinder mounting points;
• It is difficult to select timing gears to replace worn ones;
• Oil is leaking at the joints.

More details about the disadvantages...

Small resource

Unlike engines of analogue imported motorcycles, the service life of the IMZ-8.103-10 engine before repair is small, from 20 to 45 thousand km, which is explained by increased wear of the crank and piston group parts. Increased wear is a consequence of insufficient air cooling, as well as not very good quality of parts (material, manufacturing accuracy).

Difficulty starting or won't start at all

For the most part, starting the IMZ-8.103-10 engine is difficult when the ignition, fuel supply and clearances in the valves of the gas distribution mechanism (between the rods and rocker arms) are not adjusted. The reason may be reduced compression in the cylinders, clogged carburetor jets, water in the carburetors, spark plugs not working, a failed condenser, a lean mixture of fuel coming from the carburetors (too much fuel).

In hot weather it gets very hot in low gears

Unfortunately, air cooling has a detrimental effect on the engine when operating in hot weather. Therefore, in hot weather, when driving in lower gears, overheating should not be allowed, so it is necessary to stop more often to cool the engine. If the engine is new, it can easily overheat.

Interruptions in cylinder operation

To a greater extent, interruptions in the operation of the cylinders are caused by the lack of synchronous operation of the cylinders due to different amounts of the supplied combustible mixture, and by a violation in the adjustment of the valves.

Knocking

The cause of engine knocking may be: pre-ignition; overheat; wear of pistons, rings, fingers; wear of the crankshaft main bearings; valve adjustment is incorrect.

High fuel consumption

Carburetors are simple and uneconomical, the consumption even according to the instruction manual is like that of a Zhiguli, but in reality it is even higher. During the Soviet era, they didn’t think about efficiency, and drivers poured gasoline into the ground; there was nowhere to put it. These fuel costs are too high for a motorcycle these days.

There are a sufficient number of cases of inaccuracy in the manufacture of the engine crankcase at the cylinder mounting points

This leads to overheating of the cylinder due to the difference in size until the upper plane of the pistons at top dead center aligns with the upper edge of the cylinders. In the event that one of the cylinders overheats and there is no cure for this, as an option it is necessary to check whether the piston at its highest point reaches the upper plane of the cylinder; if not, then this is the problem. To eliminate overheating, it is necessary to achieve symmetrical dimensions, for which purpose the gaskets are removed from under one of the cylinders, and in its place a heat-resistant sealant is used when installing the cylinder. It is possible to install a thinner gasket.

It is difficult to find timing gears to replace worn ones

This problem is associated with the difficulty of finding a set of gears (gears) corresponding to the size group of the crankcase with the dimensional indices. There are a lot of these gears on sale, but there are no markings (indices) on them, or there is a designation, but it is not suitable. You can read about the correspondence of gear indexes and crankcase size groups here.

Oil leaks at joints

This disease does not affect engine operation, leaks are minor. But the engine, which is dirty with dust adhering to the oil, has to be washed. Tightening the head covers and oil pan does not help. After replacing the seals, after some time the oil begins to leak again. It also leaks along the valve rod guide bushing seals.

In conclusion, many people probably thought that the IMZ-8.103-10 engine is just a bucket of bolts... Well, what can we do, since childhood we are accustomed to delving into motorcycles, or rather, repairing them. Therefore, many people miss rebuilding the engine with their own hands. This is of course a joke, but every joke has some truth. In general, if you properly monitor the engine and carry out timely maintenance, then of course you can take it. With high consumption, the problem is solved by installing one carburetor from the car. The engine is very simple and very easy to repair. The engine, like the Ural motorcycle itself, is well suited for tuning.

PS Dear owners of Ural vehicles with IMZ-8.103-10 engines! You can write about your identified shortcomings and weaknesses or ask your question.

It just so happens that this is my first motorcycle. In general, I like to turn nuts, but I really don’t like lying under the car in the lotus position, which is why the idea of ​​getting an old motorcycle came up. The wind in the face and so on on the list was secondary at that time, the soul asked for an epic batch with iron. You could afford to take on a necro-Asian or neo-Asian, but in this case, either the money is right away and go for a ride, or the money is right away and then again and again, and a stable job only appeared. I remembered how my grandfather’s Ural, the frantic howl of the transmission, the infernal sound of the engine, the feeling that the stroller was about to tip over overtook me as a child... The decision was not made spontaneously, I carried it for about a year, during which time I was looking for a motorcycle, certainly with documents and fully complete. And he was found. My father helped, he brought him in to expand the search area, because my searches on Avito throughout the city and region did not bring much fruit - either there were no documents, or there was a hellish shortage. And then one day an acquaintance tells him that a friend is selling a motorcycle:

IMZ 8.103-10, popularly known as “stool”, manufactured in 1989, with a mileage of 18 thousand kilometers. The owner is deceased, the man was in charge, at that time it was the only transport, he was looked after. The widow entered into an inheritance, decided to do some minor renovations in the house, hired that same friend, and paid for the work with a motorcycle - take it, when you find a buyer, let them come to me, I’ll give you the documents. And so it happened. Within a week the motorcycle was re-registered.

Upon inspection, it was revealed that the engine was breathing quite a bit, the compression was 6/4 - I concluded that the piston was running out, I bargained (although it was not the piston, on the right head the exhaust valve did not move along the guide bushing, but the bushing moved along the body of the head, hence and gas breakthrough into the crankcase, this was established a year later). Reverse gear was also engaged, the electrics worked according to the mood. The rest is a firehorse, and two buckets of spare parts with a tool to boot.

I got down to business and decided to first eliminate the cause of the fouled spark plugs, the mixture was extremely rich, the carbon deposits were not oily. I won’t tire the reader’s brain, six months later I simply threw away the carburetors, because the horse died, it’s time to get off. The ignition was also replaced with a microprocessor-based SOVEK with a two-terminal coil: I bought a used right head, there was no point in restoring the original one - the screw for the spark plug + the mounting hole for the guide bushing was drilled out + oval. I replaced the guide bushings with TRW cast iron bushings from some BMW, installed new valves made by AMZ in Lugansk, cutting the seats and unrolling the bushings, ground them, spilled them - OK. A separate story about the tool - countersinks from the market are simply terrible, rate the “quality” of chamfering below, I’m tired of grinding. Then the carburetors came in for replacement. I purchased the now popular Keihin PZ30 replicas.

And the motorcycle came to life and could finally travel for dozens of kilometers. But I was already involved, my hands were itching for capital investments in repairs...

In the winter from 2022 to 2022, I bought an engine with an IMZ 8.103-30 from 1985, which had covered 24 thousand km, and decided to practice with it. I won’t bore the reader with disassembly, cleaning (I recommend Pro-foam 1000) and troubleshooting, I’ll just say that the only things I didn’t throw out were the engine crankcase, the rear crankshaft support and the cylinders. Everything else went to metal acceptance, except for the crank and camshaft (they later helped in selecting timing gears). I replaced the crankshaft with a restored one in Irbit, installed forged pistons produced by Autotekhnologiya, Kolbenshmidt piston rings, selected a set of timing gears from good used ones, koyo and skf bearings, corteco oil seals, more modern camshafts and pushers with rotating heels. I'll add some photos:

As a result, by the summer of 2019, the motorcycle was at least poorly assembled, technically speaking. The engine needed to be broken in, so the sidecar was disconnected. I bought KBMTS roll bars, a battery from a UPS (no starter was supposed to be used) and slowly started riding in the evenings in the fresh air. I realized that the brakes are disgusting, and the performance of the front fork is good for driving across the field, but for the rest it is absolutely not suitable. A hydropneumatic fork from Izh-Orion turned up with a front wheel, with disc brakes, with a machine from a Ducatti monster, traverses and bearings adapted for the Urals (I successfully bought it from a boxer who was dismantling his solyak). And the condition of the parts was close to excellent. God, how I rejoiced at this fork, and I still do. And at least somehow it became possible to slow down. Since the front wheel became 18 inches, I decided to buy 18-inch wheels for both the rear axle and the sidecar; I also successfully bought a set of wheels with chrome rims and hubs from Ural-tourist. I installed a Chinese accelerated main pair in the gearbox (nine). It looked something like this: 2022 ended with the engine running 14 hours without problems (about 600 kilometers), and staying in the village with my parents for the winter. Before the winter, I took him for a walk to the village where the Urals began for me, the same monster from which I grumbled so much as a child. I hit the opposite side of the fields, which had not heard these archaic motorcycles for years... A pictorial image against the backdrop of an abandoned house and garage, in which that same grandfather’s Ural once lived:

And for some time I found that peace of mind, a kind of peace, as if this journey was not in vain, all for the sake of that moment from the last photograph. Yes, that was my thrill.

2020 began with a pandemic and dim prospects. The bike wasn't as ready as I wanted it to be. The restoration had to be crowned with fresh painting and live wiring, bringing the technical component to mind. I drove the motorcycle back to the city: I disassembled everything into bolts, except the power unit and transmission, and, of course, the suspension. Installed a wing from Orion. I adjusted the gap in the front brake system and rubbed the disc on the caliper. I replaced the front optics - the headlight housing from the K-750 - the classic headlight with an egg, integrated the original speedometer, new warning lamps into it, and replaced the module with optics from BOSCH for the H4 lamp. The turner turned out adequate steering columns. I installed the passenger handles from the Ural solo. I bought stainless steel mufflers, two pipes, I always wanted a double-barreled shotgun. Air filter housing from M-72 with paper filter element. Mirrors from Wolf. The turn signals are from Java... I don’t remember everything now. The timing cover on the engine was replaced with a more modern one, with an upper breather outlet. I cleaned the rust on the frame down to the metal, where there was none - matted the paint, primed it, and painted it matte black. The tank, rear fender, air filter housing were also cleaned, the rust was etched with phosphoric acid, neutralized with alcohol and painted. I ordered wiring with unloading relays for all consumers + with fuses, it turned out great:

The switching unit disappeared under the seat. The regulator installed the relay with diagnostics (control lamps for power supply and charging are integrated into the relay). I put everything together, then took it apart again, adjusted it, set it up, put it back together... And now I’m riding in the sun

In total, after more than two years of repairs, collecting, searching for artifacts and my tendency to travel to places where there have been no people for a long time, the motorcycle was named Stalker. From the original factory, it still has: a frame with a pendulum and footrests, a tank, a rear fender with a hinged one, a seat and a steering wheel. In monetary terms - about 120 thousand rubles. In man hours - I don’t want to think, I’m not a mechanic, not an engineer by training, everything was comprehended for a long time, tediously, digging deep, giving pleasure. If any of the readers need advice, names, passwords, appearances, I will be happy to help. That's all.