74 z1 cams and head ported - rpm redline question

HI guys,
I've posted on here a couple times before.
Quick question about rpm redline and where the bike is making power.

Bike setup:
- weisco 1015
- kenny harmon L1 cams - .400" lift / 256 duration at 50
- Larry C street ported head
- APE valvetrain. springs / valves / guides
- tsubaki camilla cam chain
- keihin crs29 carbs
- kerker
- dyna s

So here is my situation:
The bike runs great. Rips super hard. I love it.
The bike has normal power at lower rpms, and then around 6,500 rpm it really starts pulling, and it pull strong all the way to 11k rpm.
Shit, it'd probably make power past 11k rpm. It just wants to keep pulling.

Don't overly judge me, but I never timed my cams to get the exact lobe degree numbers.
I have adjustable cams gears.
I made the cams perfectly face each other... then I advanced the intake in a hair, and retarded the exhaust a hair.

I'm aware that fine tuning the cam lobe degrees will shift power around in the power band.
105 / 105 will be higher rpm power, where 110 / 110 will be broad across the range.

My main question is... everything feels great and I want to leave it as-is.
If i'm really juicing it... Is revving to 11k rpm okay with the APE valvetrain?
Can the springs handle it with my cam set up
The Larry street port head seems to flow at that rpm pretty well.

I guess I'm looking for some input if i'm playing with fire revving to 11k.
What have you guys experienced?

I guess I could go and actually have the bike dyno'd... to see where power falls off.
But that still won't tell me when valve float is or could occur.

Any thoughts / feedback welcome.
Thank you.
Ed

Super cool bike you got there!

Personally, I'd spring for the dyno tuning to check mixture and find out where the power peak is. Your tach may be off some too so that would be a good time to verify that.

Did you have the crank welded during the build?

Don't take this the wrong way but considering you got yourself a 40 year old bike there I'd keep the rpm's down to some conservative ceiling. I just don't see the point in trying to push the bike for every ounce of power.

I would not be revving it that high.

There was a guy on KZ650INFO who would regularly run his engine up to 11,000 rpm and even a little more. I suggested that was not a good thing to do if he wanted his engine to last, plus max power is made far below 11,000 rpm. The KZ650 makes max hp at 8,500 rpm even though it has a 9,000 rpm redline. Of course, he ignored the warning. After a couple months he reported the engine was trashed. The pistons and valves had collided making a total mess of things. He suspected the con rods had stretched, but this was never confirmed. Ed

11000 rpm is really on the limit for the crank.
Over that the bearing rollers break the oil film and start to skid and as already mentioned you are into valve float territory.
I've had mine easily pull to 12 a couple of times but it's not really necessary.
If it's more speed you are after then maybe raising the gearing will do the trick if it will pull it.

Maybe run your set by Larry C.... since its his head bet he'd know. I push mine to 500 in the red at times and have hit 7- 800 a few times in 5th with a good tail wind but can tell that's about the limit.

Mine pulls the same after redline. In fact I shifted too late and a car pulled on me at about 11,000. When I'm running it hard I'll shift after 9 or so where the gearing will pull me faster.
Steve

Stock tachs are very inaccurate, and highly optimistic!!!! When I ran a stock tach on my Superbike, I shifted at a indicated 11,000RPM. When I got my hands on a highly accurate Kawasaki road race tach, that very same motor and gearing would not pull over 9,500RPM on that tach. Big difference don't you think. So 11,000RPM on a stock tach is most likely pretty close to an actual engine RPM of 9,000 to 9,500RPM. Watch Ebay a few of these Kawasaki road race tachs show every once and awhile.

Dr. Gamma wrote: Stock tachs are very inaccurate, and highly optimistic!!!!....

I'm sure some are inaccurate, but some stock tachs actually are pretty accurate. If one has a Cylinder Balance Analyzer or some other quality dwell meter device that measures rpm the accuracy of the tach is easy to check. I found the tach on my KZ650-C1 was very accurate when I checked it using the MAC tool shown below. Ed

Like you say Ed some are less accurate I'm sure but our 650 tacks can't be too bad as 9,500 with stock gearing works out to be 126 mph about what our bikes are suppose to top out at.