kz 650 top speed stock motor?

Ive read alot of stuff on these bikes and ive owned 2 of them but the most i have been able to get out of one is just under 170kph. Is that right for a 1978 kz650 not that its not fast enough but the top speed on eveything I have read says around 186kph or just under 200kph? The engine in my bike now has just under 50000km on it and my other motor has only 18000km on it but its not in a bike its a spare. Anyone with any thoughs on this topic it would be appreciated. Allmost forgot my bike has pod filters and is jetted 110 main 17.5 pilot and piped.

You guys all make good points im 240lb and wind resitance would be high on my 650 with over a foot of ground clearence but my bikes alot lighter than stock. I dont need it to go faster anything faster than 140 or so gets me a little nervous. Now 10 years ago I would have had it wide open more than 75% of the time. Just in case your wondering my bike is the kz650sm dual sport in the gallery.

Post edited by: Dalley, at: 2007/09/12 19:43

Post edited by: Dalley, at: 2007/09/13 16:46[img size=150][/img][img size=150][/img][img size=150][/img][img size=150][/img]

Post edited by: Dalley, at: 2007/09/13 16:52

Well on the Kz550 I got it up to about 150 or so...only a custom pipe...I think you should be able to get it over 175 on yours

In stock form, with a 150 lb rider, a new KZ650 would run up to roughly 119 mph or 191 kph. See original Cycle World road test at:

www.kz650.info/articles/documents/KZ650%...World%20Roadtest.pdf

My '77 KZ650C1, with about 45,400 miles (73,000 kilometers) will still run up to an indicated 120mph, and although there may be some speedometer error, I don't believe it's off by more than 4 or 5%. I believe it's moving about 115 mph (185 kph) with me (200lbs) aboard. My bike is completely stock, nothing ever done to it other than regular maintenance (I know because I'm the original owner). If your bike tops out at 105 mph (170 kph) I'd say there is a problem. Not that 105 mph isn't fast for driving on the street, but these bikes are capable of more. I'm guessing that because your bike has been modified (pipe, pods, carb settings) performance has been reduced. There aren't many of us who have access to the same research, development, and testing resources that Kawasaki Heavy Industries used when developing these machines, consequently, many modified bikes sacrifice actual performance when being "re-engineered" by their owners. However, before you try to improve performance through tuning or changing parts, be sure to check the number of teeth on the sprockets to be sure someone didn't change the overall ratio. Mine has 16 teeth on the engine sprocket; 42 on the rear. Ed

Back in 77 the KZ650 set a bunch of world records in the 750 class.
AMA 10 miles 131.018
FIM 100 Km 133.726 and
AMA/FIM 24 hr. 117.125.
Mark

Post edited by: Mark Wing, at: 2007/09/12 22:23

I think the 1977 in the magazines did 119mph, the KZ1000 122mph so the 650 was pretty darn fast for it's day. Too lazy to convert to km/hr but that gets you an idea if you want to convert it over.

i've had my stock (minus kerker and pods) only up to 110mph.
i'm sure if I was a little more streamlined, i could've got a couple more out of it
but , why the hell do i need to go that fast for?

I would be hard pressed to hit a true 110 mph with my tweaked 650/810 given the gearing I have in the bike today, but when I first owned the bike back in the early 80's I was young and stupid enough to have it up to 115 mph as indicated on the speedo. I would be willing to bet that if the police had me on the clock back then it would have been a shade under 110.

Now if I played with the sprocket combination, an honest 120 might be doable-maybe, but this old adrenaline junkie certainly wouldn't be the pilot.

The bike speed runs as published are often done under ideal temperature, wind and tuning conditions and are difficult if not impossbile to replicate. A perfect example of this would be the 1/4 mile times that Pee Wee Gleason ran on the apparently stock Kz650 whic came in around the 13 flat range.

I would hazard a guess that few if any 650 owners ever matched this impressive time for a middleweight driven by a 135 pro, lightweight driver.

Cheers-Colin Firth-Ontario Canada

remember this guy?
he was running 14.80 in the quarter on a stock 650 with pods and a open header and a two step?
he is a little more then 135lbs.


his whole thing was his reaction times.
he's a big boy but damm he could race!

I wonder if somethings Kawasaki did slowed some of these bikes down. Emissions crap for one, I have heard stories of de-tuned carbs ...if nothing else its another 2lbs of crap.

but i bet the big one is the heavy mag wheels and triple disk set ups. I would think all that extra weight would hurt the top speed.

Just a thought.

A little bit of weight won't hurt top speed, just acceleration. Top speed is a fight against wind resistance and rolling resistance. Weight would only be a factor going up-hill.

Of course, a really heavy rider would affect rolling resistance and wind resistance, but only a couple pounds won't matter.

Post edited by: loudhvx, at: 2007/09/13 12:45

got a 122 mph out of mine all stock but a header on it my wieght 170 pounds, no wind on a flat 1977 Kz650
has mechanical carbs . Ive owned 8 of these kz650's still have the one odometer 42320 miles on it
not shy with the throttle .left the Yamaha 850 midnight special at the via vanishing point horzion
bikes are incredably fast no dought shift point on the bike likes 10.5 rpm to 11k rpm Bike now is an antique!
Still runs strong Engine tune is not to specs of manual could never get um to run right Tuned on the fly carbs set while my but is on it haulin beans hehe down the road I call it the Nija.s grandpappy .

Clearly the original poster had a messed up bike; probably resulting from the mods on it. For one thing, he said his bike has OVER A FOOT of ground clearance. It must be on stilts or have 30 inch wheels :laugh: the original geometry gave the bike 5.7 inches of ground clearance Who knows what else had been done to that bike. Ed