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Discussion Starter #1
Have two bikes, same mileage, one has to go. ( other is a 650 Vstrom ).








Never dropped. Dealer serviced. All touring miles ( I work from home ).

* Givi top case and Daylong seat are optional - open to chat.

Can deliver anywhere in upper eastern US or Ontario.
Price is in US dollars. Open to reasonable offers on a fast sale.
Run all day at 80 mph +

Power mirrors
Power windscreen
Clearview windscreen ( 3.5" wider for hand coverage )
Heated grips
Shaft drive
ABS

This Canadian version has the heated grips and can have the heated seat if I switch it back to stock.

Email is preferred contact.
 

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Never dropped. Dealer serviced. All touring miles.

Shaft drive

  • Never dropped? So for curiosity, where is the muffler cover?
  • All Touring Miles? And just how many of them are there?
  • Shaft Drive? And the answer is?
 

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Discussion Starter #4
shaft drive - Thinking of my ST1100...
63k km
kid dropped the battery charger on the plastic plate which is stupid expensive to replace.

Immaterial anyway as should be sold tomorrow if all works out.
 

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Registered
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Discussion Starter #5
shaft drive - Thinking of my ST1100...
63k km
kid dropped the battery charger on the plastic plate which is stupid expensive to replace.

Immaterial anyway as should be sold tomorrow if all works out.

••••

came across this explanation of the final drive on the Burgman. Well done..

Whyfore art thou, Gear-train final drive?
Ever since the many comments suggesting that the B650 might benefit from a final drive other than the enclosed spur-gear train it's got, I've been thinking about it, trying to get into the rationale that the engineers used to decide on that engineering solution, and I am pretty sure i've got the answer. First let's review the options:

in the world of motorcycles, there are three types of final drive:

1. open chain
2. open toothed belt
3. enclosed shaft

in the world of scooters, there are two (besides the suzuki spur-gear train peculiar to the B650),

1. the fiber cvt V-belt. (in which the drive pully and driven pulley in the CVT are part of the swingarm)
2. manual transmission transverse shaft drive (as in the original Piaggio design for the Vespa, with the engine contained in a side pannier)

Of the motorcycle systems, open chain drive is arguably the lightest system (at the rear wheel, where unsprung weight matters), but it's also arguably the dirtiest, and highest maintenance, needing regular adjustment and luburication. further, chain drive likes a long swingarm in order to attenuate the tendency of the chain/swingarm system to cause squat under acceleration. (beyond what simple weight transfer does)

In chain drive systems, the countershaft sprocket and swingarm pivot are different lengths from the final drive sprocket, a geometry which causes the chain to loosen and tighten as the swing arm moves (the swing arm is describing an arc of shorter radius than the chain, see?) Because the chain is pulling over the top of the final drive sprocket, it's constanly trying to "shorten" the chain, and pull the swingarm up, which has the effect of compressing the rear suspension.

Open toothed belt is as comparably light as open chain, but has the disadvantage of requiring a far wider and larger diameter sprocket set for an equivalent level of horsepower. The toothed belt needs more tooth contact area (needs to engage a greater number of teeth) in order to not tear teeth off the belt. Also, the belt needs to travel over larger radius curves that a roller chain does, in order to not over stress and tear the fabric reinforcement. It likes to be semi-enclosed (take a look at the upper and lower belt gaurds on any HD or other belt-drive bike) because belt drive is very susceptible to damage from road debris, the most susceptible of any final drive system.

As with chain drive, belt also has the geometry that causes the rear supension to compress under aceleration.

Both systems require a method of length adjustment, or tensioning, though belts don't require the regular checking and tensioning/lubing of chains.

Both these systems, while in and of themselves perhaps lighter than a train of spurm gears, need to have the swingarm supporting them sized strong enough to support the motorcycle to which they are attached: perhaps your wheel/sprocket/brake assembly is as light as a GSXR, but the motorcycle is 200 lbs heavier.The required swingarm will be have to be strong enough to support that heavier bike, and thus the benefit of the lighter final drive system is partially negated. understand why?

Shaft drive is arguably the heaviest of motorcycle final drive systems, but has the advantages of being relatively maintenance free (beyond checking and adding/changing fluid) and clean. Unfortunately though, it has negative effects on suspension action, in the form of shaft jacking.

For those not familiar with shaft drive bikes, shaft jacking is the phenomenon of the swing arm raising the bike up under acceleration, and dropping it down under deceleration. Shaft jacking happens because the small pinion gear on the end of the driveshaft tries to "climb" the larger ring gear on the rear wheel, causing the swingarm to act as a lever on the chassis. On the throttle, the pinion climbs up the ring gear, and the swingarm levers the chassis up, extending the suspension. Off the throttle, it climbs down, levering the chassis down and compressing the suspension.

A few motorcycle manufacturers (BMW & MotoGuzzi for two examples) have developed double-jointed parallelogram shaft drive swingarms that eliminate shaft jacking, but these systems are complex, heavy, and EXPENSIVE (not something you'd prefer to use on a bike built to a reasonable price point goal as is the AN650)

Scooters have shied away from these motorcycle systems, and used integral powertrains: the engine, transmission, final drive and drive wheel, are all one unit. There are advantages to this, which include simplicity, compactness, cleanliness, full enclosure/protection of the drive system, etc, but offer significant disadvantages in how the unsprung weight of the drive system affects the suspension action and response - especially when the scooters start becoming bigger and heavier.

Ordinarily, these scooter drive systems will locate the the suspension pivot at a point that allows the engine to counterweight the CVT and rear wheel somewhat, but this is only a management of that weight, not elimination, since the inertia of the mass of the engine must be accelerated/decelerated with every movement of the suspension. Whenever you add mass to a suspension system, it's response is slowed by the increase in inertia it must overcome to move or change direction. Additionally, the spring/damper units must be sized to control that extra mass, again, increasing weight and slowing suspension response.

Now, this isn't so bad down in the smaller displacements: 50cc, 125cc, 150 cc, and the like...even 250cc isn't too bad. But a 400cc single isn't particularly light, and it's CVT transmission has to be big enough to handle it's power and the structure of the swingarm has to hold it all together without flexing AND contain the CVT, and... well you get the picture.

...It is a tribute to the mfgrs that produce 400-500cc maxis with these integral powertains that they handle as well as they do...

But now we come to the B650...the biggest and heaviest of them all.

Let's imagine, for a minute, that we're engineers on the design team tasked with figuring out the AN650 final drive.

THe B650 is a maxi scooter, and since it's a scooter, we want it to embody traditional scooter characteristics, inlcuding a step-thru body, large internal storage, twist and go operation, enclosed final drive, and low maintnenance. We don't want to force scooter riders to adopt the hassle of chain maintenance, right? (even enclosed oil bath chain drives require periodic adjustment, roller chain cam shaft chain drive, with it's automatic - or manual - adjustment is a good example) and the sprocket sizes required of an open belt drive are prohibitive, especially if we are going to use wheels generally smaller than those on motorcycles, in keeping with the "scooter" architecture.

A step thru design and large internal underseat storage forces us to adopt an engine layed flat, and we're building a liquid-cooled 650 twin, which will be so heavy as to make including it as part of an integral drivetrain unrealistic, especially once the size and weight of a CVT able to handle it's power is factored in. (take a look at CVT pulleys in 50 hp snowmobiles for reference. they ain't small)

Since we are putting a rather high specific output engine in this vehicle (11:1 compression, DOHC, fuel injected, with 50+ hp from 39 cubic inches? Puh-LEEZE, this thing's a HOT ROD ) we might as well give it a CVT that's a bit overbuilt, control it electronically and incorporate some automotive features - multi-shift-mode functionality - which would be convenient, and convey a sense of "high content". But it's so heavy, we definitely can't include that in the swingarm either.

so we've got our powertrain figured out, how do we get that power to the rear wheel?

well, we eliminate chain and belt right off the top, given their respective higher maintenance and sprocket size issues reasons listed above. There's always shaft drive...but we don't want the bike to suffer from shaft jacking...and since the layed-down engine and transmission unit is already forcing us into a long wheelbase, we don't have enough room to apply the usual first method of attenuating shaft jacking, which is, make the swing arm really long, so it doesn't have so much leverage on the chassis. An articulated parallelogram swingarm? uhh...$$$, and weight. we've got a price point to meet boys, so, nope. maybe on the 1000cc version.

How about a spur gear train? we make the CVT output shaft concentric with the swingarm pivot, and spline it to the first gear in the train, which rotates in the direction of travel. we use a 5 gear train - one input, 3 idlers, and the final drive gear - in which the 2nd and 4th gears rotate opposite the direction of travel, effectively cancelling most of the leverage the drive gear on the wheel might apply to the swingarm. we use straight cut gears, to get the greatest tooth strength, and size the gears so that we can enclose the whole train in a reasonably sized four-wall aluminum box, which will give us a swingarm that's nicely stiff in torsion and bending (just like the boxed aluminum swingarms on our GSXRs) and then we can make the other side a simple cast C-channel with some strengthening webs, so we can save a couple bucks there. The CVT will attenuate some driveline lash, and we can carefully control manufaturing tolerances in the gear train to eliminate as much lash as possible there, using current market acceptable shaft-drive tolerances as our baseline

the train of gears themselves might weigh as much as a steel driveshaft, but the spur gear on the wheel is smaller than the usual ring gear of an equivalent shaft drive ring and pinion.

there you have it. once you think through all the choices and options, given the size and operating parameters of the B650, the spur-gear train final drive makes sense.
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