Top end and 1/4 mi times

First off my dad's bike is a 1978 KZ1000. His mods are:
-1075 kit
-29 smoothbores
-head work
-Accel ignition
-V&H drag pipe
-maybe some other small stuff
-not sure about his gearing

We went to Beaver Springs Dragway this past weekend and he ran a consistent 12.3 w/ no slick or bars. Now the thing that gets me is the bike has no top end. He ran a 98 mph in the 1/8th but only went 107 in the 1/4.

Are these kind of times typical for similarly modded 1000s? And what can we do for more top end?

Just a FYI, he is talking about selling it next spring and getting Hayabusa. But I would probably buy the KZ. Now if I buy it I will be driving it as many days a year I can. I would change the pipe though because it doesn't pass emissions.

Post edited by: Dtowncats, at: 2006/07/24 10:36

1/4 mile ET and mph look right, but the 1/8 mile mph seems high, sure it's not 88 mph? those darn et slips can be pretty hard to read sometimes.

Hmmmm... I have no experience with the 1000s, but it seems a little slow for the mods you've listed. A stock KZ650 could do low 13s, so I'm sure one modded correctly could hit near the numbers you mentioned.

those numbers are pretty good for that bike with those mods,chopstar let me guess you read some old magazines and they said 650's could run 13's all day right?
do not believe everything you read.seriously 12.3 on a 30yr old bike with simple mods c'mon thats pretty good how fast do you think it should be?

Post edited by: fastestz1, at: 2006/07/24 12:11

Hello Dtowncats! Three comments. (1)If you are drag racing the ET wins the race...not top end. (2)Where do you live that requires emissions tests on pre-smog bikes? (3)Tell your dad to forget the hayabusa and buy the new Kawasaki ZX14:)

Although I didn't see an 1/8th ET, your ET/MPH fall in-line. Do not expect to pick-up alot of Mph after the 1/8th because remember you are accelerating from 100 mph for roughly the next 5 seconds for that second 1/8th mile and the acceleration rate has fallen off considerady at that point. Even Top Fuelers don't pick-up big mph after the i/8th, atleast nowhere near at the rate they did for the first 1/8th. I would expect an average bike with your listed modifications and stock cams to run about like it is. I think you would find a new set of cams that were "properly" degreed-in, would pick it up alot. There are many factors that add up to your dragstrip times. Weigh,grearing, engine state of tune and rider skill/weight just to name a few.....mod

Post edited by: modprod, at: 2006/07/24 12:45

fastestz1 wrote:

those numbers are pretty good for that bike with those mods,chopstar let me guess you read some old magazines and they said 650's could run 13's all day right?
do not believe everything you read.seriously 12.3 on a 30yr old bike with simple mods c'mon thats pretty good how fast do you think it should be?<br><br>Post edited by: fastestz1, at: 2006/07/24 12:11

Like I said... I'm no expert, but I've seen timeslips from a friends 1978 GS1000E (with pretty much the same mods), and it could break into the high 11s consistently. I just thought that maybe the KZ could break the 12 mark - that's all.

12.3 sounds ok to me. We used to run a 650 with a GPz750 top end and 1000 carbs and that ran pretty much the same numbers. Probably made 75hp at the wheel. I don't know if that's normal for a 1075 or not. How much does dad weigh?

remember most magazine tests were done with 90 pound horsejockeys like pee wee gleason back when these bikes came out.temperature, traction ,rider,altitude and lots of other variables figure in to this.a bike that runs 11s on one track might be lucky to run 13s on a differant track,you have to be running under same conditions to compare one bikes times to another.

Hey Gang - I posted my 1/8th times and speed a couple of weeks back when I ran at the strip. Since the bike only had about 250 miles on the new motor I made a conscious effort to shift at 10 grand on each run. Since then I have regularly spun the motor past 10 and it pulls strong all the way up to 11.5 on the tach.

So. here's what I brought to the track (Miss July on the 2006 Kzrider calendar.)

1977 Kz650/810 that has 750 cams, valves, Gpz springs, ported and milled 650 head, WG Mikuni 28's, velocity stacks, 130 rear tire, Dyna ignition, Mac pipe, 14 tooth sprocket (down from the stock 16) I had an irritating flat spot or bogging around the 7 grand range in each gear that probably collectively cost me at least half a second. I pulled around 9 grand in fourth gear crossing the finish line and never got the bike into fifth. My speeds were in the 82-85 mph range and times were 8.9 seconds.

I am very experienced in getting the most out of a bike but this was my first time hammering it through the gears on a track with a Christmas Tree setting me on my way. I learned that launch technique and reaction time can make a whole lot of difference.

Next time around I will have the flat spot dialed out, shift a little higher and know what to expect at the tree. I am very confident that I will get into the high 7's for the eight which is pretty quick for a 30 year old middleweight:)

Oh ya, I gotta add this part....A couple of nights ago I had some fun on the street with my buddy who rides an '88 Katana 600 and he couldn't even come close to me off the line or on a roll.

With my admittedly limited dragstrip experience, my take on your Dad's times are they are pretty close to what I would expect based on the bike's mods.

Cheers-Colin Firth-Ontario Canada

Post edited by: reborn650, at: 2006/07/24 19:08

Post edited by: modprod, at: 2006/07/24 21:23

"I am very experienced in getting the most out of a bike but this was my first time hammering it through the gears on a track with a Christmas Tree setting me on my way. I learned that launch technique and reaction time can make a whole lot of difference"




Reaction times are a critcal factor in winning a race but have "absolutely no effect whatsoever" on ET. A Redlight or even if you sit there after the green has no effect on ET. ET timers do not start until you leave the (stage) beam this also stops the (reaction timer) but the 2 have no effect on the other. The strip tells you how fast the bike/rider combination is really going. Alot of first timers are dissappointed after a dose of "reality" but it is a baseline that you can measure your own improvement or not, in your riding technique and the modifications/tuning changes you do. The timers tell you alot more than the "seat of the pants". Best thing about the strip though is having a good time and winning is always more fun losing. Have fun!........mod