A sad story

The mechanic that built me a engine drag raced a Kawasaki 900 for 30 years. He told me he shifts at 8500. He told me that you are not gaining anything by going any higher in the RPM range and are just beating the engine. The engine he built was a 1075 and will go well beyond 8500 but why beat the engine. The engine was built 12 years ago.

Just get the valve stems tipped and you should be good to go.

racer54 wrote: WOW!!! 11,000-11,200 rpm? Mine runs best shifting right at 8500 rpm. I've tried different rpm levels to shift and I always seem to run best shifting at 8500 rpm.

That's about where I shift my dads 1198cc KZ1000. No point in winding it out if it isn't pulling.

I'd say the guy would have to be fairly deaf and dumb to bend some valves. For one, I know valve float starts in at 11,500 on my stock 900 and you'd have to be fairly dumb to take an unfamiliar bike that you don't own that far past redline when the power dropped off a long time ago. I know you'd have to be a bit past the 9,000 rpm redline before downshifting to bend valves on my bike.
I'd love to know what he did to it to bend some valves.

The stock KZ650 engine makes maximum power at 500 rpm lower than redline. I'm quite sure the KZ900, KZ1000, etc. have similar power curves - you can verify this by looking in the front of the Kawasaki Service Manual. Power drops off dramatically after redline is reached. Running the engine above redline might sound like the engine is making power, but on a stock engine it is not; it is simply abusing the engine for no reason other than hearing it whine. I have read of more than one KZ engine that met an early demise from running at 10 - 11,000 rpm.

Regarding the B/F's BS excuse that he "did not realize the red line was so low" - I don't buy it for one second. Is he so stupid that he cannot read a tachometer? If so, discourage him from marrying your daughter; we do not need folks as dumb as he (or as mean if he blew up your engine for kicks) procreating. Ed

LOL. Ed, you break me up. Having come from a racing background, I can state that the power curves you show are very standard among stock cams. The aware rider should feel and hear the power dropping off and shift accordingly.
There are rare exceptions; my GPz is still pulling when it hits the 10,700 rpm rev limiter of its 1000R Ninja ignitor. But it keeps me from overreving the engine and causing valve float as in this instance.

crazyduck,
(and anyone that wants to compare z1900 to kz1000 rpms)
you have to remember that a z1 crank weighs somewhere in the neighborhood of nine pounds lighter than a 1000 crank.
take nine pounds off any crank and it will rev much free'er :evil: .

leon

I run mine up to and over 10,500 on a all the time and its pulling like a mf-er all the way with no laying over, valve float or loss of power....I know there is more in it....

but my wife keeps my balls in a jar in the curio cabinet on the second shelf next to precious moments chit ..... :blink:

25 years of marriage.... :dry:

No offense intended, but I fervently hope the B/F listens to your daughter more closely than he did that poor, over-revved engine...As a divorcee myself, I can tell you that IS a deal breaker! LOL! Come to think of it, when she was screaming at me,my ex kinda sounded like valves floating...
(Or a concrete cutter!)

How are we judging our rpms at shift point for the sake of this discussion? Quick glance at the factory tach? Or are we capturing data some how?

The reason that I say this is that when I installed the data logging equipment on my bike, I discovered that the factory tach was a bit optimistic. It would read a good 300 rpm high at idle. Who knows what the error was at speed. I'm now taking a rpm reading digitally from my Dyna 2000 ignition. Based on preliminary testing with my Veypor VR3, my torque curve starts to point downward at 8500 rpm on my 78 KZ1000 with a Z1 crank, factory pistons, factory cams, 29mm smoothbores, k&n pods, and 4 into 1 stainless exaust.

testarossa wrote: How are we judging our rpms at shift point for the sake of this discussion? Quick glance at the factory tach? Or are we capturing data some how?

The reason that I say this is that when I installed the data logging equipment on my bike, I discovered that the factory tach was a bit optimistic. It would read a good 300 rpm high at idle. Who knows what the error was at speed. I'm now taking a rpm reading digitally from my Dyna 2000 ignition. Based on preliminary testing with my Veypor VR3, my torque curve starts to point downward at 8500 rpm on my 78 KZ1000 with a Z1 crank, factory pistons, factory cams, 29mm smoothbores, k&n pods, and 4 into 1 stainless exaust.

_______________________________________________________________________________________________

I have a auto gauge 5" pro tack with a programmable shift light. I set shift light to come on at 10,500, plus you cant miss read the thing its freggin huge.... The tach is 100% correct.

The engine is highly built and is not stock. It has a trick crank, non KZ worked rods and one off valve train.

I had Pearson do everything possible to the rotating assembly that he knew from decades of KZ builds, some of which he wouldn't tell me what he did (no shit)?. This is why I am able to spin it to these high RPM numbers. I knew that this was good money spent as the lower end is so important to get right. I am also running a different spring package on the valve train which is not a KZ item in any way.

4TheKZ1000 wrote: I have a auto gauge 5" pro tack with a programmable shift light. I set shift light to come on at 10,500, plus you cant miss read the thing its freggin huge.... The tach is 100% correct.

The engine is highly built and is not stock. It has a trick crank, non KZ worked rods and one off valve train.

I had Pearson do everything possible to the rotating assembly that he knew from decades of KZ builds, some of which he wouldn't tell me what he did (no shit)?. This is why I am able to spin it to these high RPM numbers. I knew that this was good money spent as the lower end is so important to get right. I am also running a different spring package on the valve train which is not a KZ item in any way.

It's good that you point that out. I would hate to see guys nuking their bikes thinking that they can spin them to the moon with a stock build. I don't race my bike, so I set the rev limiter on the Dyna to 9500. That way I have a bit of safety margin built in.

I have heard that stock roller bearings can come apart above 10,000 rpm. I don't really want to find out for myself, and since I don't race, it is a non-issue to me.

I just wanted to point out that the stock tach might not be returning accurate rpm readings, and therefor the percepetion of the bike pulling to 11,000 rpm plus might be based on false information. Only a dyno test would prove otherwise.

To Z1Driver,
Didn't the boyfriend notice the rather large red line that begins at 9,000rpm on your tachometer? That would be my first clue, especially given that he was riding a loner bike in this case. I try to take special care of anything loaned to me. Maybe I was raised different. Sorry to hear of your misfortune.

The fact that he managed to bend all of the intake valves sounds like a combination of too fast and a loose cam chain. The engine pulls the cams on the exhaust side but the cam pulls the chain up on the intake side. Also, your tensioner is on the intake side.

The Shop Manual lists the amount you can take off the end of the intake valves safely. It isn't much, though, so you might be better off looking for some short intake valves.

In spite of the technical stuff, there's no excuse for running the bike of your (possibly) future father-in-law that hard. If he abuses your bike, how soon before he starts abusing your daughter.