what is a xs650 true top speed?

[wildcard]

ok. acording to the net these bikes are only suposed to do 100 but ive had mine up to 100 and it was still ganning so my question is, how fast can a stock 650 run? i had to back off because my bike started shaking really bad.(balled back tire).

[grizld1]

First off, let's not have any posting of urban myth here: you know, the story about the cousin of a friend who had a friend who knew a guy at a shop in Bumblast, Nebraska who had a box-stock XS 650 that would do 140 mph after he tweaked a screw somewhere.

Top speed very much depends on the XS650; some motors are in better shape than others, and some come off the assembly line faster than others (and that's still true of modern machines, even with today's higher precision). Theoretical top speed (top speed in 5th gear at engine redline of 7500 rpm) with stock gearing and tire profile is around 112.5 mph for Specials and 115 mph for Standards. It's a rare stocker that will pull to redline in 5th. Bear in mind that at high speeds tires deform, vibration makes mechanical instruments lie, and all kinds of things can happen to convince a rider that his bike is moving a lot faster than it really is. That having been said, any reasonably healthy XS650 should be able to achieve low triple digit speeds.

[wildcard]

ok. i was just wondering.

[Tom Graham]

Mine seems to run fine but even though it is in reasonable tune, it isn't "like new". I frequently take the bike to an indicated 100mph. My bike might go 110 but the ton is enough of a struggle for the old girl. One hundred mph is plenty fast on an old bike.

Tom
Just back from a 200 mile twisty backroad ride on the XS.

[richard]

I have the 32 tooth rear sprocket on my 71 and I’ve had it up to 90, it seemed like it would do more, but crashing into a dog at speed years ago gave me a mental governor that starts to kick in at anything over 75. Funny how the older you get the less important top speed becomes.

[headcase]

You could tie it to the rear of the ex-cop car here in the drive if you want. It'll peg the buck-forty speedo

[richard]

LOL! ;D

[kopcicle]

let's see , 32 ft/sec x 32 ft/sec with an irregular tumbling surface of approximately 20 sq/ft .
it would depend on the the mean air density as well as the rate and type of irregular tumble of the object . It's entirely possible that that said object may be somewhat faster in the thinner air of higher altitudes . Also the addition of a small drogue of just enough area to stabilize the object may actually increase terminal velocity . Best guess in this case would be in the 180 to 192 mph range .

for those of you that didn't get it on the first read through this is an estimate for and XS650 dropped from a significant height , like from an aircraft .

~kop

[kopcicle]

Okay , the old coots can correct me but around the mile in like 34's and backing them in at about 128-130 ??

~kop

[grizld1]

Thanks, kop. The man 's question refers to stockers, but it's useful to have what you can expect from a well-built, full-blown race motor as a point of reference, the better to debunk the tall tales.

[XS Rod]

So Kop... let me get this straight... the application of the drogue chute is to place the AoA perpendicular to the crash site... is that correct? Thus reducing the frontal mass of one's beloved XS in free-fall...My question is will it fall faster than an F-4 with both engines flamed out?
Note: the F-4 shares the theoretical glide ratio of a brick...
Sooo can we say a XS 650 is as fast as a F-4? I think I hit that speed one night... but it hurts if I think that hard...

[kopcicle]

Just keep in mind that it isn't the fall that gets ya , it's the sudden stop at the bottom ...

~kop

[XS Rod]

those immovable objects in life's path are a pita.

[KAMAKAZEE]

How long is a piece of string

It all depends on what is done to the motor and the weight of the rider. I had a black chopped xs once (the bike in my avatar) that would pull 125 mph. There was no way that motor had not been hotted up but I never had it apart to find out. I also had a dead stock TXA that would pull 115mph. At the time of owning those bikes I was round the 12 stone mark in weight.

[headcase]

In response to the original question, it would all depend on the speed rating of the tires on the trailer onto which the bike rests, and the gonads of the vehicle pulling it. Just make sure it's strapped down tight.