My XS is an oddball?

Classic

Classic

rackin' up the miles
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A few recent threads have made me realize that i may have been misinformed of my bike's history. Many videos of XS650's that i've seen recently show the bike pulling steadily at 85mph but not accelerating hard... when i roll on the throttle my XS screams passed 85mph. The first many times I rode my bike it was running one cylinder due to a no-good plug wire. A friend of mine dared me to push the bike and I made a run up to 107mph... It was still pulling. After getting the plug wires and caps sorted i was able to bury the 120mph Speedometer. Everything appeared stock to me. Since then i have been through several speedometers and they all indicate the same speed in accordance with RPM.

What kinds of mods could the p.o. have done that would change an XS like this?

I checked out the jugs and they say a normal 653cc.
My timing has always been about 48BTDC because it has no balls ands runs like ass when set to 40BTDC.
 
Don't worry about it and enjoy it.
 
take a GPS and see how fast it goes. GPS are pretty good for steady state speed not so much for acceleration. It's possible you have a 750 kit in there.
 
Or maybe a performance cam. In WW1 and WW2 the sniper rifles weren't built they were found. The military kept their eyes out for rifles that were shooting more accurately in the field and refitted those as marksman rifles. I guess you have a sniper rifle there!
 
Didn't the magazine test specs indicate a 114mph top speed? 120 from a well tuned 650 twin is believable to me especially from an optimistic indicator.
I've had the Troublemaker to a tick under 100 indicated and she was still pulling well.
 
shaas said:
Didn't the magazine test specs indicate a 114mph top speed? 120 from a well tuned 650 twin is believable to me especially from an optimistic indicator.
I've had the Troublemaker to a tick under 100 indicated and she was still pulling well.
Click to expand...
I believe a Cycle World I have somewhere says: Top Speed, 117(Rev Limited).....
gggGary said:
take a GPS and see how fast it goes. GPS are pretty good for steady state speed not so much for acceleration. It's possible you have a 750 kit in there.
Click to expand...
The jugs say 653....
The GPS I used records an AVG, MAX, and MIN speeds in meters per second. At the end of a run it read 55 m/s for MAX. I was at 8400 revs and the clutch was slipping like a sonofabish....
 
Classic said:
I believe a Cycle World I have somewhere says: Top Speed, 117(Rev Limited).....

The jugs say 653....
The GPS I used records an AVG, MAX, and MIN speeds in meters per second. At the end of a run it read 55 m/s for MAX. I was at 8400 revs and the clutch was slipping like a sonofabish....
Click to expand...

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=55+m/s+in+mph :eek:

You can resleeve 650cc jugs to 750cc, mikes has a kit. Could be that. Try popping your spark plugs and seeing if it's rephased? Probably can't tell if you have an aftermarket cam without taking the head off though.

And 8400 didn't float the valves? Dyaaamnnn, I'm way too nice to my XS.
 
7500 is red line. I would never take it past that even if it is still pulling. unless I was running from the fuzz or going to a hot date!:doh:
 
My bike likes a redline of 9,500RPM. :D

Did a 3rd gear full throttle pull for you guys at 3:11.

And 28Mph (and a power wheelie) in my driveway HAHAHA

 
xander18 said:
http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=55+m/s+in+mph :eek:

You can resleeve 650cc jugs to 750cc, mikes has a kit. Could be that. Try popping your spark plugs and seeing if it's rephased? Probably can't tell if you have an aftermarket cam without taking the head off though.
Click to expand...
Jugs say 653CC's... it's not rephased (single lobe on points). I've been riding this bike nearly every day of the riding seasons for three years.
And 8400 didn't float the valves? Dyaaamnnn, I'm way too nice to my XS.
Click to expand...
I've been told 8,250 floats valves but Hugh and I have both pushed to 10,000RPM and beyond......
 
those are not 650 gauges. ratios are not the same I would bet. 9500 rpm's on a xs650? something is funny here. your speedo reads 85 how do you get 120+mph, my:twocents:
 
I was hit head on by an idiot in an Accord earlier this season. I had to swap my entire front end for one from a Maxim.

I've paced my brother on his CBR954RR. The speedo is correct.
I've checked my RPM's on GearingCommander.com and the graphs here. The tach is correct.
The bike had a 120mph speedo when I got it but that fell apart. I replaced it with another 120mph.... after the accident I went with a Maxim(85mph) speedo.
 
Last edited:
Thinking about your original question of what mods could have been done, I'm considering stuff that would just increase the revs. Maybe a good job balancing the crank? Stronger valve springs (no floating)? Lightweight pistons/rods?
 

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