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50.000km in two and a half year

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50.000km in two and a half year

PostAuthor: faffi » Sat Aug 03, 2019 4:07 pm

Back when the bike was new, MOTORRAD magazine in Germany rode the Yamaha XVS650 Dragstar Custom, aka V-Star 650 Custom, more than 30.000 miles before taking the whole machine completely apart. This is their result, translated to English by yours truly.

Yamaha responds...
...to the leaky valves.
We see no reason not to put the valves back into the engine. However, the burned seats need to be re-cut and the valves lapped in.
…to the wear, the seize marks and discoloration on the piston pin and upper connecting rod small end bearing surface.
The piston pins must definitely be replaced. The con rods must be replaced, or precision bronze bushings inserted. We know this kind of wear from other engines and other makers. The lubrication for the piston pin is unfortunately poor due to its design and placement. We would have liked to see bushings inserted from the factory.
…to the worn-out pistons.
Very disappointing to watch. There is no way around fitting new pistons. We presume it stems from unusually hard use by the testers.
…to the seize- and scoring marks in the cylinders.
Here, the only way out is boring and honing and fitting oversize pistons.
…to the extreme pitting on one of the pinions for fifth gear.
Since only one of the pinions are affected, we presume it’s a production defect on the damaged gear. It must be replaced, something we would do even for bikes out of warranty.
…to the pitting starting to show on the bevel gear on the output shaft.
This is a known problem that only affect the very first bikes made. Since 1997, the production tolerances have been continuously improved.
…to the loud gear-changes when the engine is cold.
This isn’t nice to experience, but has no technical influence on reliability or functionality.
…to the clutch, that only engage at the very end of lever travel.
The pressure point isn’t very accurately defined, but we have had no customer or dealer complaints to indicate this is troublesome.
…to the poor cold running when the engine is cold.
A result of the lean jetting required to adhere to the emission regulations.

Condition after 50.000 km (31.000 mi.)
Valvetrain: Camshafts and rocker arms in very good condition. Valve stems and valve guides fine. Burned exhaust valve seats. Several valves leaking.
Pistons, cylinders and crankshaft: Both cylinder bores with heavy scoring and seizure marks, must be bored and honed. Pistons totally worn out and must be replaced. Piston pins discolored and carrying seizure marks, as does the small end bearing surface. Con rod must be replaced or bushed. Big end bearings with some marks, but can be reused. Crankshaft in good condition.
Clutch: Considering the mileage, the hub, basket and clutch plates look really good.
Gearbox: One pinion of the fifth gear must be replaced due to heavy pitting. All other parts of the gearbox in good condition. The bevel gear on the output shaft shows signs of pitting.
Exhaust: Upper muffler was replaced under warranty after 1800 km (1150 mi), the lower at 36.000 km (22.500 mi) due to vibration damage. At that stage, it had also consumed to sets of front brake pads and a set of rear brake shoes.
Chassis: Only very slight corrosion on frame and swingarm. Painted parts fine. Lower steering stem bearing with slight indentations. Switchgear, instrument and electrical system in good condition.
During the test, the retaining bolt for the gear shift lever vibrated out, the license plate vibrated off and after 22.000 km (13.500 mi) the engine was loud enough to worry every tester. But it ran just fine and didn’t consume more oil, so the test continued. After the completed distance, the bike ran faster then when new, despite the wear issues inside the engine.
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Re: 50.000km in two and a half year

PostAuthor: Arjay » Sat Aug 03, 2019 6:53 pm

Not exactly sure what results are expected. Was there scheduled maintenance like oil changes? How hard where they ridden? Too many variables to consider. Now if this where a study of those bikes years later at salvage yards then to me that would be a more honest evaluation of how well they functioned. Once I had a VW bus with a broke steering wheel. Back then I scoured one of the best salvages in my area. Strange because each VW had same split/crack. The point being that nothing compares to regular use. Some guy on youtube did a nationwide study to see what cars lasted the longest. So he gathered sales info from Craigslist on running car for sale with most milage. First place winner surprized me, the Lincoln town car with an average of 500k miles. Next was Toyota camry with something like 400k. Anyway, it's the conditions.

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Re: 50.000km in two and a half year

PostAuthor: faffi » Sun Aug 04, 2019 2:15 pm

The magazine perform a number of these tests every year. All bikes are serviced on schedule (more or less; not always possible to get the exact schedule fitted when on a very long ride through multiple countries, so sometimes they will service the bike a bit early or late, but nothing dramatic) by a certified dealer. The bikes are ridden by a number of riders, ranging from racers to secretaries. The bikes are also used for short commutes, errands, day trips and vacation rides. I would say that overall, they are ridden harder than average. Still, I think they have merit. Also because they always invite as many readers as possible to share their experiences, several of which are printed along with their own results. There are times when they support the findings of the magazine, and times where the test bike seems to be a standout. Finally, representatives from the manufacturer and/or importer are present during the strip-down and allowed to comment on the findings.

If we look back through history - the magazine have done long term tests since the 1970s, then doing 25,000 km - I can say that with moderate use like most cruisers see, the XVS650 engine will likely survive 4 times the distance the magazine ran it for. Why? Well, back in the day, this magazine wore out engines like the KZ1000, R80, CB750, GS1000 and XJ650 - all known for very good longevity - in 25,000 km. Or less.
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