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Yamaha TRX 850 endurance test

The X-Files

The TRX 850 completed the endurance test distance of 50,000 kilometers without any mysterious incidents. Whether she hides secrets deep inside?

What a cheek: comes a slim Japanese woman and throws the gauntlet into the middle of the terrain of Italian engineers. In fact, the Yamaha TRX 850 with its large-volume two-cylinder aimed directly at fast Italo-Twins – and promptly had to be insulted as a disdainful Ducati copy even before it was available at dealers in 1996. The dispute raged even louder when the Japan twin won its first comparison test against the 900 SS. The facts were almost overwhelming, and even today the TRX with its problem-free engine, decent chassis, its almost touring character and acceptable price is one of the serious sizes in the sporty two-cylinder segment. Reason enough for MOTORRAD to put this model to the test.
From January 1996 the black Yamaha enriched the MOTORRAD long-term test fleet, bought from the authorized dealer Motorcorner in Wangen, and the prevailing bad weather conditions at the beginning of the year could not slow down the general TRX euphoria and the exuberant zest for action of the test drivers. Nothing was given to the Yamaha, so the positive end result should be anticipated: after 50000 kilometers without problems, even the dismantled engine is still pleasing. Just annoying that the manifold clamps had to be removed with force when removing the engine. A little copper paste on the manifold studs during the initial assembly and nothing would have been a problem. The condition of the engine (see also boxes on pages 38 and 39) promises another tens of thousands of kilometers, only the exhaust valves and their seats need revision by a specialist.
No wonder, then, that a rather emotional remark adorns the first page of the logbook: "Sounds good, almost like a Ducati." Right, it couldn’t be otherwise, because a crank pin offset of 270 degrees, which is completely nonsensical from a technical point of view, results in the former parallel win an ignition sequence like a 90-degree V-engine. Its characteristic sound included.
»Great, easy to ride sports bike. Only the fork is a little slack and the brakes could be a little bit more snappy, ”is the deeper tenor of further logbook entries. The screwdrivers in the editorial office immediately pricked up their ears and began looking for a solution. Tighter fork springs and different fork oil should bring the fork into shape. Replacement fork springs and fork oil from White Power already brought a significant improvement. The best results were delivered by the replacement springs including the oil from Hyperpro (Hagen sports accessories, phone 0911/936950). Not too tight and responsive, they give the fork the reserves and puncture resistance that the sports riders in the editorial office want. Mini Koch took on the subject of brakes (see also MOTORRAD issue 2/1997). Not that the original brake is bad. But a real sports driver imagines his stoppers differently, demands a high braking effect with little manual force. However, none of the retrofit brake pads achieved a real advantage. Improvement in terms of pressure point and controllability resulted in the installation of steel braided brake lines, but if you want a real two-finger brake system, you have to make more profound modifications.
Other logbook entries show that the TRX was not only used for sport, but also carried out a number of vacation trips. Test driver Helmut Faidt was not the only one who complained about the seat cushion, which was too uncomfortable for long journeys. However, apart from Heli, nobody came up with the idea of ​​putting their very best we have pillow. A retrofit seat cushion from Haungs Kunstofftechnik (phone 07264/4561), which began to remove its seat cover shortly before the end of the test, provided better seating comfort and an additional reduction in seat height.
The low thirst and the associated high range of the long-term test TRX are pleasing for sports and touring riders alike. Consumption values ​​between a fabulous 3.5 liters minimum and around 8.5 liters maximum resulted in an average consumption of around 6.7 liters / 100km over the entire test distance.
On the other hand, the hard throttle response and the strong load change reactions of the large two-cylinder did not please. A remedy is promised by a carburetor kit from Dynojet (Moto Parts, Krefeld, phone 02151/557374), which – tried on another test vehicle – actually ensured a smooth throttle response and thus significantly reduced load change reactions. However, this intervention in the interior of the carburettor invalidates the vehicle ABE. The drivers of the long-term test TRX therefore had to continue to bother with the original set-up.
The TRX reacted sensitively to some tires. The sporty rubbers from Metzeler (ME Z 1), Pirelli (MTR 01/02) and Michelin (TX 15/25) are highly recommended for sports drivers. The Bridgestone BT 56, which were also tried out, could not particularly convince on the long-term TRX test. Driving tests with other machines of the same type show that this tire is also recommended. The MOTORRAD tire test in the TRX tire sizes in MOTORRAD issue 11 and 12/1997 provides further information.
AT.It’s easy, right? Not quite. Guest driver Biggi Sandoval had to report a broken handbrake get up and a dented muffler after a careless southerner had pushed her and the Yamaha roughly into the center of an Italian intersection. The man was kind of distracted, but that happens when a normal woman is out and about on an attractive bike. Or so.

Yamaha takes a stand

…….. Regarding the width of the exhaust valve seats that is greater than the tolerance: The wear in the area of ​​the thermally highly stressed exhaust valves is completely normal according to the mileage. The deficiency can be remedied by re-milling the valve seats on the inner edge and the cylinder head can be reused without hesitation ………… to the hammered sealing surfaces of the inlet valves: The problem is known at Yamaha. The hard surface of the valves from the first year of construction is a bit too thin and can lead to the aforementioned wear. From the 97 model onwards, modified valves with a thicker stellite layer are installed in all five-valve models, which can also be easily retrofitted in older models. The spare part number for the corresponding parts has changed from 00 to 01. The valves affected here should be replaced ………. in addition to the joint clearance of a piston ring that has reached the wear limit: The cause is difficult to determine, but could be due to too large a clearance when new ….. …. to the seizure marks in the upper connecting rod eyes and the deposits on the piston pin: The material application or removal on both parts comes from components that are not 100% round when new. This symptom is only a blemish, connecting rods and piston pins can be used without hesitation ……… to the manifold studs corroded in the manifold flanges: Since the flanges are heavily exposed to splashing water and dirt, this degree of corrosion is normal. An assembly of the exhaust flanges using copper paste prevents this problem ……. to the slightly knocked out guides of the carburettor slide: The wear is appropriate to the mileage. The carburetors and slides can be used without hesitation.

Reading experiences

TRX 850 drivers like to be sporty. There is only criticism for the too soft fork and the blunt brake. On the other hand, the high reliability and low consumption are praised. Most would buy it again immediately. After 20 years of Ducati bevel shafts, a brand change was inevitable in October 1996. After 11,000 kilometers with my TRX 850 so far, I have to say: it hit the mark. By increasing the fork oil volume and switching to Bridgestone BT 57 tires, the TRX now has a first-class chassis. The powerful engine torque and the comfortable seating position also make longer tours pleasant. The low consumption of the TRX 850 is also pleasing. The pillion seat is only suitable for my five and nine year old sons. What is missing but cannot be missing: a main stand. What I personally miss: the vertical shafts. Otherwise a very good machine, for relatively little money. Johannes Klein, Meerbusch In August 1997 I will be 50 years old and the TRX is my thirty-fifth motorcycle – but I’ve never had so much fun as with this device. If you frighten drivers of significantly larger machines, which is not a great art, the effect of the rather inconspicuous TRX 850 is further enhanced. But that fits the whole motorcycle. You are not so fast because of the engine power, but because everything is perfectly coordinated. Yamaha has created a motorcycle with unparalleled maneuverability and reasonable straight-line stability. Apart from installing the Metzeler ME Z 1 instead of the Michelin Macadam 90 X, I will not make any further technical changes. This is how I come to the conclusion: This motorcycle is the coolest sports equipment with high touring suitability that I have ever owned. Heiner Jedele, Motzingen The Yamaha TRX 850, that would be my motorcycle. However, it has a seat height of 79 cm. My husband said: We can do that. The seat bench was padded by approx. 5 cm, the fork pushed upwards by approx. 2 cm and the tension struts of the rear suspension were lengthened by 18 mm. After these modifications, the seat height is only 68 cm and I am now standing with both feet firmly on the floor. The handlebar, which was too far forward for me, was replaced by a superbike handlebar and the problem was solved. What still needed to be improved were the tires. After assembling the Metzeler ME Z 1, my dream motorcycle was finally perfect. As a driver license holder, I still have a lot of respect for my bike, but thanks to the modifications, the TRX is easy to control even by little people. Andrea Meyer, Norvenich

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