Track times

[TonimusMaximus]

Allright guys. I've got a question. If I took my mostly stock (slightly modified exhaust) '78 standard out to the track, what should i XSpect to get a 1/4 mile in? Honest times for stock, not theoretical numbers. Thanks guys.

[John]

According to the articles written about the XS11 on it's introduction in 78, the times were estimated to be in the high 11's. The articles are here in XS11.com. Just look at the yellow border to the left of the screen, click on articles and select the ones for the 78 model. That was probably with a pro rider, and new transmission. In the real world, I'll bet 12's are possible with a good running stock machine, and novice rider. Still fast enough to shut down one of my co workers 5 point slow Mustang. Repetedly...

[turbox79]

You also have to take altitude as a consideration because at sea level your going to run alot faster than up here in the mile high but high 12s is close and every test you see done is always sea level.

[dfrooney]

I notice you're in Phoenix...If you want your best times, go now while it's cool. I moved here last summer and my bike is noticably slower when the temps are in the 100 degree range. Cooler air is denser and allows for more powerful combustion.

[MartyA]

There was a thread on this a while back. I think we have a dragster among us. For the best times it was about slipping the clutch properly. Due to the driveshaft and everything else, the XS is not optimized for launching. If I recall, if you launch at 3500 RPM you will bog, if you launch at 4500 you will spin the tire.

If you get a chance at the track let us know!

[TonimusMaximus]

A working brake system would be nice before I take her out to the track. And I need to fix her breathing problem. Exhaust outlet size at the moment is about 3 inches in diameter.

[Pat Kelly]

Firebird has a nice long shutdown area whith that high-speed sweeping left hander at the end ..... don't need no stinkin' brakes.

I rode out there almost daily when Firebird was being built (the lake was before my time). I race at Beeline a few times too (anyone remember Beeline?). Firebird and PIR is where I did 99% of my roadracing (I won't mention South Mountain). Raced Riverside twice before it became condos.

Ahhhh.... the memories

[dragxs11]

Hey tony, I tried it once this last fall, but my 2nd gear slipped twice, so I didn't try it again. By summer I should be ready to go. I have to move 2nd gear, get kevlar friction plates for the clutch and bore it out yet before the 70 degree days come back. Seeing as I've done everything I can to it short of a turbo or NOS, I will hopefully drop into the low 11's here at 5000 feet. We'll see what I can do then.
Matt

[chevy45412001]

track times

Ive run my 82 xj11 at the track several times. To date the best time ive got is 13.12 at 102.something mph.Thats 1/4 mile time in south east wisconsin. Ive been tunning on this thing for two years now.only mods are 4-1 kerker and remove stock airbox. Jetting is all i was playing with.The bike has 42,000 miles

[chevy45412001]

p.s.

I really wish i would have left stock air box on. That bike was blistering fast before i removed it. Seems like i never really got back the tourqe it had before.

[MartyA]

"...was blistering fast..."

Can you get it back on? Curious, from what I understand all the theories say freeing up the intake, 4-1 free flow exhaust, and jets get you more top end, which I would think would show up in the 1/4 mile trials. Does that mean you lost some bottom / middle power?

By the way, 13.12 I think is very good. The original XS was around 11.9 with a pro and fresh engine. Where are you shifting? How do you launch? Which tire do you use? Are you keeping track of the results with the different jets?

[chevy45412001]

yes i lost a lot of lower end torque. As for shifting its by feel i power shift when the engine just starts to level out in a gear.Ive tried taking off at 3500 (like the guy said erlier) but a bad stumble.So i usualy take off like im at a traffic signal. Very slow at first,then hit it hard and go to work.I usualy cut a good light in the .05 or .06 range. Just a basic tire from the bike shop.I only keep track of my times at the strip each time i jet it gets better or worse so i know witch way to go. Hope this helps.

[pgg]

Chev, I'm picking your CV carbs aren't lifting the slides efficiently due to the missing airbox creating a lower vaccuum through the barrels.

[pgg]

Tominus, out of curiosity I did some 400 metre runs the other day. All very unofficial mind you. First up, on a deserted back road, I measured out 400 metres with the accurate digital speedo I use for a back-up. I spray painted a line on the road. The small digital speedo also has a stop-watch setting that starts up immediately the wheels move. I did a few blasts down my 'strip', and each time I flashed past the paint line I glanced at the dial. Nearly every run was in the 11 second bracket. Max speed was around the 170 k.p.h. mark. Getting a good take-off is crucial.

The motor is quite tricked up so the bike's possibly 1/2 to 1 sec quicker than standard? Anyway I'm picking 12 sec runs should be easy enough on a well tuned stock bike. 11 sec bracket if you're skinny and light. I'm 200 lbs stark naked (keep that horrible nasty sight out of mind) and with heavy leather jacket, boots, gloves, helmet etc.. I'm looking at way over 200lbs. Most bike-mag testers are probably half that. Throw in altitude, temperature and tailwinds, and there'll be all sorts of variations.

[Renegade]

Originally posted by MartyA
There was a thread on this a while back. I think we have a dragster among us. For the best times it was about slipping the clutch properly. Due to the driveshaft and everything else, the XS is not optimized for launching. If I recall, if you launch at 3500 RPM you will bog, if you launch at 4500 you will spin the tire.

If you get a chance at the track let us know!

Tires and rider weight will affect the launch technique too. I only weigh in at 145lb, so it is like a gnat on a buffalo's back from the bike's perspective. I tried several methods when I was running a Bridgestone SF22 rear on my Special. The most effective launch with that setup was to start out slipping the clutch at about 3500rpm until the bike had rolled about two feet, release the clutch fully and snap the throttle open at the same time, shifting at about 6000rpm. It would leave a 20ft wavy black streak with the front wheel staying about a foot off the ground until I hit 3rd gear, and be gone quick enough to pick on the plastic crotch rockets stoplight to stoplight.
I just put a new set of Dunlops on last week, and that same method produced a near vertical wheelie with no wheelspin, and a serious panic attack before I finally got the front end to come down.