Any of you guys had your XS's down the 1/4 ?

OK, but back in the world of urban adventure for the elderly I decide to ride to the downtown street sale on my stock XS650 that's never been apart from new, Senior Citizen at the controls, Velorex sidecar attached and running 17/36 sprockets.
Vigorously accelerating as the light goes green on 22nd street the bike will get to the next light just after it turns red.
Repeat the sequence all the way down town.
But just sometimes CN Rail sends a slow goods train across 22nd street at Avenue D.
Then I have a choice between letting the engine overheat as it idles and annoying all the guys lined up behind me as I try and get the motor started again.
Then I get down town and try to remember WTF I wanted at the street sale. Ah yes! Bargains!
 
I think there was only one report that got 13.8 out of the box most reports were around 14.3

Jay760, there you am! Yes, finding those published reports is difficult, especially for the early XS1s. Lotsa hype back then, the horsepower wars, plus folks crying 'foul' when the jap factories used 80lb blackbelt ninja-jockeys.

I have got 12.18 from mine at 110mph, I have 750 JE pistons megacycle 250 30 cam with after market valves standard size, head has been ported and the combustion chamber altered, biggest problem I have is I'm over 200lbs...

Yep, got you on the list.

... there is someone in the UK that is running around 11.5 second quarters at 116 mph his has 750 Wiseco pistons a ground cam ( not hard welded ) and mild porting but he only weighs around 150 lbs,

Back in the day, I was 145-150 lbs. Even *that* was heavy by some folks' standards.
I found your run times PDF, did some cut/snip/paste to isolate what I think may be the fellow(s) you're speaking of.
Can you confirm these are XS650s?

BritDrags-2014.jpg


I'm hoping to be in the 11's sometime but if it can get there with me riding is another thing

Sounds like we need a "Lose 80lbs program", possibly headed up by Fredintoon...
 
I have built many drag bikes over the years and the first 60' is a killer. If you get that down and can launch bike hard enough you can get some good times. Gearing is next and it always helps if you stretch the bike a little
 
...The results from the May sprint this year are here, they are a bit better than the ones above,

Both the Yamaha's in 13d are xs650's I think it's fair to say neither of us are going to beat the other bike in our category a GSX1100 fitted with a 1255cc kit...

Great, Jay, I've clipped-out the XS650s, circled the best times, and will add them to the above list.
Are you the J. Winterson on the XS707?

XS650/750 11.46 @ 116mph (R. Broom mod, Brit)
XS650/707 12.18 @ 110mph (J. Winterson mod, Brit)

BritDrags-2016.jpg
 
Yes that is me J Winterson, though it says the bike is 707cc it's 750, it started at 707 a few years ago and has gradually developed fron there,
The class I'm in doesn't allow extended swing arms could probably get away with an inch or so but nothing too much.
 
Yes that is me J Winterson, though it says the bike is 707cc it's 750, it started at 707 a few years ago and has gradually developed fron there...

Okay, dug thru some of your older posts and I see that 750cc in there.
Very respectable times and speeds.

Have you looked into the early 70-71 tranny, with the closer 1st to 2nd ratios?
 
wow 6'90's thats fast .fastist I've been is 8'80's @172 mph and that was fly'n I'm too old and fat now to go that fast but sure miss it some times
 
I ran my road racer at Sacramento Raceway (I think it was in the early '90s) and without any gearing optimization nor a full, clutch burning start the bike ran 11.85 and 111 - 112 mph. I was trying a new engine configuration and it later dyno'd at 68 RWHP. The bike weighed 315 with some fuel and I am 190 with all my gear on.
 
TwoMany, the low weight is the result of a C&J dirt track frame, Kosman rear hub, fiberglass body work, clip-ons, alloy rims, hollow axle, single disc up front, magnesium master cylinders, small disc on the rear and lots of 7075 aluminum for the triple trees, engine & foot peg brackets, etc.
 
Okay, dug thru some of your older posts and I see that 750cc in there.
Very respectable times and speeds.

Have you looked into the early 70-71 tranny, with the closer 1st to 2nd ratios?

Yes he is very quick, about 5/6 years ago when I started his times were around 12.5 seconds, mine were around 13.5, I've managed to get my time down by well over a second, unfurtunately so has he.
If I'm totally honest I wouldn't know if I was looking at an xs1 gearbox, is there any significant indication that it's different, and which way are the gears closer, is first a lot longer or second lower, if that makes sense,
 
... I wouldn't know if I was looking at an xs1 gearbox, is there any significant indication that it's different, and which way are the gears closer, is first a lot longer or second lower, if that makes sense,

Hey, Jay. 70-71 1st gear was a bit taller than the later models. It puts 1st closer to 2nd, potentially closing the torque gap that exists there. In this XS1 chart, notice that the torque-vs-rpm graph is converted to thrust-vs-speed. The optimum shift points are at the line crossings.

XS1-XS2-Performance.jpg


Now, have a look at mrriggs charts in these threads:

http://www.xs650.com/threads/performance-more-power-and-higher-top-end.36563/
http://www.xs650.com/threads/gearing-for-your-best-performance.36605/

He's looking to close-up that 1st-2nd power drop. Of course, for this to have any meaning for your bike, you'd have to get your specific torque charts, then transpose them into a thrust-vs-speed chart, to see if you have a significant drop in 1st-to-2nd. A wide torque band in those rpms may make this change unnecessary. A narrow torque band in those rpms may indicate improvements with the early trans.

From what I've gathered from other info, swapping a trans should be drop-in, assuming you're swapping complete (original unmolested) both-shaft units. The kickstart is another issue, different toothcount to accomodate the 1st gear change. There was a change to the shiftdrum, but have no usable info on that.

I've been gathering tranny info from a variety of places, to put together a chart of some type that shows the changes over the years. A bit of a backburner project, this gets kinda complicated.

Things to consider in a 447 to 256 swap is the higher 1st gear (makes it a closer ratio), plus the slightly easier kickstart effort.

Here's the work-in-progress (as of 1-1-2015)

XS650 transmission evolution

*** Starting 1970 XS1, 256-parts

1st gear: 14t mainshaft, 31t countershaft, 26t kickstart
26/14 (1.857:1) kickstart ratio (See INXS thread on Kickstart)

*** Starting 1970 XS1, 256-parts, after s/n 001235

Change to mainshaft needle bearing OD, only cases changed.

*** Starting 1972 XS2, 306-parts

Change to 1st gear ratio
1st gear: 13t mainshaft, 32t countershaft, 25t kickstart
25/13 (1.923:1) kickstart ratio, harder to kick (See INXS thread on Kickstart)
Changes to shiftdrum, interchangability unknown. (to be done)

*** Starting 1977 XS650D, mid production at 1T3-721262

Changes to splines of both shafts and ALL gears.
Old shaft/splines have polished valley bottom.
New shaft/splines have polished spline tops.
5th gear shaft OD changed from 0.979" to 0.975" (uncertain)
5th gear wheel ID changed from 0.984" to 0.979" (uncertain)

Some changes to other parts, bearings and shims. (to be done)

*** Starting 1980 XS650G

(to be done)

*** MikesXS 5th gear change

5th gear wheel updated from 23t to 24t
Same gear diameter, same diametrical pitch, accomodated by slight change to depth of tooth valleys, involute gearface geometry remains unchanged.
Recommended to use his matching 05-0857 22t countershaft gear, possibly to match new gearface geometry.


You'd also have to change the sprocket(s) to make use of that taller 1st. That will upset your entire strategy with the other gears, maybe worse or better, depending on what's happening as you cross the traps...
 
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Yesterday I took my XS650se to the strip (Springmount Raceway FNQueensland) It has rephrased crank 277-83, mikes 750 kit, ports cleanup, mild street cam, pamco, ign., Vm 34's, balanced PMA (hughs). Ran 14.7 @ 90 mph, I sure a lighter rider with good reaction times & aggrisve start would do wonders, I changed the gearing from 17-32 to 17-36 & was getting though the traps @ 7500 rpm in 4th gear. It was bracket racing so times & speed where a bit irrelevant, yep I'd liked to have gone a bit faster but it was a lot of fun, most of the other bikes in the pre 89 class where mid 80's sport bike's (Bought for a song in unloved condition get them running then flog them death on the strip) so if you won't to go fast on buget & save the mighty XS for normal duties this is the way to go
 
13.55 but I was being a girl with the clutch..... And Jay760 was over a second quicker, hey I'll ride it if you build I weigh nothing man....
 
Hey, hey! Way to go Jay!
Congratulations!

Updated the list in post #15.

You're right in there alongside the Harley V-Rod.
Must've been a good/hard launch...
 
theres a drag team still using a fairly stock xs650 at mackay qld .. racing in the bracket class .. if you look up h2 racing on f/b they have a couple of vidios , with camera set up on bike , 1 showing taco as well
 
Bit unexpected to be honest, I had changed the head over winter with 1mm over valves all ported with smoothed out chamber as well, virtually the same porting and combustion chamber as the one on there originally, started it up for the first time a couple of days before the race and found it was holding the slides up at 7000 revs on the dellortos I normally run so quickly put an old pair of Amals I had lying around at the back of the garage, last time I tried them there was a lull between changing gears so just raised the needle as high as it would go and strangely they ran perfectly, just the slightest hesitation off the line which probably helped as it seemed to help keep the front wheel down.
 

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