Engine damage MV Agusta F4 1000 R

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Engine damage MV Agusta F4 1000 R

Engine damage MV Agusta F4 1000 R

Bang effect

Krakkk – that ugly sound when an engine suddenly says goodbye to the afterlife is something everyone fears, especially if it happens out of the blue at full speed. As on the MV Agusta F4 1000 R.

Test drive with the MV Agusta F.4 1000 R on the Nurburgring. At high engine speed and a speed of 238 km / h, the screw connection on the right connecting rod tore and a hole was made in the engine housing. This immediately poured liters of engine oil in front of and onto the rear wheel.

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Engine damage MV Agusta F4 1000 R

Engine damage MV Agusta F4 1000 R
Bang effect

MV Agusta F4 1000 R had previously looked a bit tired and the damage did not take him completely unprepared. The data recording confirmed that the engine had already lost a little of its power in the course of the last lap until it finally burst. In the previous turn the clock showed 255 km / h at this point.

The MV Agusta F4 1000 R was then brought to the factory in Italy and dismantled there. The technicians quickly found the cause. A circlip on the overpressure valve of the oil circuit had come loose and the entire valve insert had fallen into the oil pan, causing the oil pressure to drop suddenly. And without oil pressure, connecting rod bearings only run for a few seconds. This can also be seen from the fact that the crank pin of the connecting rod concerned had become severely discolored.

The other connecting rod bearings also showed signs of imminent damage. The fact that the connecting rod bolts cracked is certainly due to the reduced strength caused by the extreme heat. Under such circumstances, a little play is enough to overload the material.

An individual case? Everything points to it. MV obtains the oil pressure valve as a complete unit from a supplier who also equips other well-known motorcycle manufacturers. At MV, the parts are checked for the required opening pressure of 6.5 bar. The fact that the valve of the test MV Agusta F4 1000 R was obviously not assembled or manufactured correctly escaped the controls at MV as well as at the manufacturer. After all, it had worked properly for over 2,500 kilometers, and the machine had already gone through a complete test program including a race track at sister magazine PS.

As MV Germany announced, a 750cc series suffered similar damage a few years ago. At that time, too, the valve had fallen out of its housing because the circlip had come loose. Which in this case led to bearing damage, but not to a connecting rod tearing off.

MOTORRAD readers will immediately remember the burst engine of the MV Agusta F4 1000 S long-term test machine when looking at the pictures. The damage pattern was identical, but the cause was different. Because the pressure relief valve was intact, and the strong discoloration as a result of the enormous temperatures had not occurred. How the damage came about back then has not yet been fully clarified, MV blamed it on machining residues in the engine. What is certain is that it was not an isolated case, in Germany alone there were several such engine failures on the S model with a similar course.

In the case of the MV Agusta F4 1000 R, these problems should actually be eliminated through design changes to the connecting rod bearings and the oil circuit. Up to now MOTORRAD is not aware of any further serious damage to R-engines.

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