OMR: '76 KZ900 Restoration/Modification

Interesting thread.

For comparsion lets look the ZXR1200R specs.
www.zrxoa.org/webpages/generalinfo/facto...cs/factoryspecs.html

1164cc
10:1 compression
4 valves per cyl.
Keihin CVK36 carbs
Kawasaki Throttle Responsive Ignition Control (K-TRIC)

Top Speed 141.1 mph
1/4 mile 11.135 sec. @ 119.775 mph
Horsepower 96.3 @ 8300 rpm
Torque 70.1 @ 5500 rpm

This is a modern high tech carbed engine. These figures are measured at the output shaft - not the rear wheels.

why is a 1000cc air cooled 4 cylinder that is over a 100 horsepower so hard to believe when these guy's used to road race these things they 130 or 140 horse with a 1025cc limit and they made them last a complete road race screaming the gut's out them for an hour or more and that was 25-30 years ago technoligy is better parts are better built and more plentiful so why can't it be done.i just don't understand why this is so hard to believe. i've built them ridden them and raced them for 15 years+ now and it is possible and does happen every day the new motor i'm putting to together should make around 170 horse if i do every thing right and so far it is looking like it is.i have no problem believing that dave's motor once it is set -up and the carbs are jetted down and the motor has a few breakin miles put on it it will make very close to 100 horsepower at the rear wheel.

timebomb33 wrote:

why is a 1000cc air cooled 4 cylinder that is over a 100 horsepower so hard to believe when these guy's used to road race these things they 130 or 140 horse with a 1025cc limit and they made them last a complete road race screaming the gut's out them for an hour or more and that was 25-30 years ago technoligy is better parts are better built and more plentiful so why can't it be done.i just don't understand why this is so hard to believe. i've built them ridden them and raced them for 15 years+ now and it is possible and does happen every day the new motor i'm putting to together should make around 170 horse if i do every thing right and so far it is looking like it is.i have no problem believing that dave's motor once it is set -up and the carbs are jetted down and the motor has a few breakin miles put on it it will make very close to 100 horsepower at the rear wheel.

At these levels your approaching ZX-14 power. You mean to tell me that a kz 1000 can match wits with a ZX-14 ? Oh boy.........this is gettin good. Do you run the infamous Terlingua Galatyn snake oyl ?

jtmcculloch wrote:

Interesting thread.

For comparsion lets look the ZXR1200R specs.
www.zrxoa.org/webpages/generalinfo/facto...cs/factoryspecs.html

1164cc
10:1 compression
4 valves per cyl.
Keihin CVK36 carbs
Kawasaki Throttle Responsive Ignition Control (K-TRIC)

Top Speed 141.1 mph
1/4 mile 11.135 sec. @ 119.775 mph
Horsepower 96.3 @ 8300 rpm
Torque 70.1 @ 5500 rpm

This is a modern high tech carbed engine. These figures are measured at the output shaft - not the rear wheels.

sure ive got no problem believing a well tuned blueprinted small bore old kaw can hang with a stock zrx,by all means ask solomrus about the old blue 78 1000 he had with really mild 1075 kit that used to whip up on his stock zrx ! :laugh:

PLUMMEN wrote:

Precisely. Hey Plummen.......pass the Hookah.

KZ vs ZX-14 - Cant wait to see that race

Well well... You boys have been busy I see. :blink:

Well all I can tell you is what was reported to me after the Dyno test... 86HP and as mentioned, on non perfectly jetted carbs.

As for reaching another 7-10hp with some additional break in period for pistons, rings, cam timing components, camshafts, new valves, and carb tweaking etc... seems to me this should be doable.

And if I only reach 90HP tops at the rear wheel, shit, I'm cool with that as well. If it stays @ 86HP, I'm good with that as well...

As mentioned previously, was running rich (same as when Dyno was performed) so dropped a clip position from 4 to 3 to lean her out which effects 1/4 to 3/4 rpm range, I also went from a 120 main jet down to 115, adjusted the pilots for more lean operations and took her for a test drive...

All I can say is this... @ 65mph, you twist the throttle you better be holding on.... :woohoo:

As for listening to several of these guys, learning and using there experiences and expertise, they haven't let me down yet, so as far as I'm concerned, I should be close to these numbers for what I've done to this motor following their guidance.

Case & point, they said when finished and dialed in, probably end up around 93-95... With non tweaked carbies came in at 86hp... I don't know about the rest of you but how much closer to what was being said compared to Dyno results can you get....

As for being offended, naw, don't sweat it for I don't take offense easily, thicker skin then that...

OMR

by the way a zx-14 has at the back wheels not at the crank like you guy's are saying about 160+ horsepower and over a hundred actually around 110 ftlbs of tourque so you would have to have one hell of a motor to keep up to that.































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I was gonna "move right along" to the next thread...but nah...what fun would that be. :lol:

Gonna hafta back-up Plummen and OMR. Their numbers are totally legit and reasonable. And I'll pull the Solumnruss card myself, the guy is a very nice guy, KNOWS his 220,000rpm induction fans, is a mechanical genius, and knows how to build a bike. I'd also throw my 40 years in on this, being born into a bike-shop (my dad's) and still stay connected to the industry (albeit loosely), although my main occupation isn't at a bike shop these days. Less than 5 years ago I worked at a shop where I got to play dyno-boy all day long. Dynos vary wildly in their numbers from dyno to dyno; your bike's power out-put is the same regardless of one dyno saying "100 bHp" and one saying "10 bHp". Biggest tool a dyno is = helps you get your bike dialed in correctly; always use the same dyno and you'll know if your mods are working. Bounce from dyno to dyno to 1.) compare dynos, or 2.) confuse youself into thinking that your PCIII (I'm sorry, your jet-kit! ) actually got you 15 bHp because you before/after tested it on different dynos. Be wise.

Having said all this, use a dyno for what it's for = excellent tuning tool.

When I was working at a motorcycle speedshop in LA in the late 90s, the lead mechanic at the shop was Chuck Grave's top mechanic and spun wrenches for some front row AMA Superbike and Supersport racers. The guy trained under Kaz Yoshima and knew his stuff; and I suspect that Pauly probably surfs this site from time to time as he's an old-school superbike kind of guy...I'd know, I gave him a ELR clone for some un-obtainium work he did for me back in the day. He worked on the old school KZs and they used an eddy/current (sp?) dyno back then and these numbers are very achievable. ZX14s put down 180 at the rear wheel...I don't recall anyone posting here that they're going to get over 180 with a 1015 kit, a bank of 29s, and some head work. :dry:

My tired old 'J' puts 89 at the rear wheel with an old 'Trapp and a set of 36mm Mikuni flat-slides (yes, it's way too much carb...I'm just sayin') with K&Ns, a ZX6R rear wheel, and 530 chain/sprocket (think I missed out on 'reciprocating mass' day in physics?:laugh: ). Stock motor. That's about right, I'd say...maybe even a little weak. I dunno, it's just an 81 KZ1000J, but that seems pretty 'right' to me. :huh:

Moving right along...:woohoo:
-KR

Old Man Rock wrote:

Sure enough, he replied 86HP and I was running really rich. Asked what jets, 120's, he said drop down to 108-110's on the main jet, adjust the pilots and re-synch I'd be good to go....

Dumb question.
Why is it nesseary to re-synch after a pilot or main jet adjustment? The slides are still in the same position.:S

fine tuning