How many r's can a kz 1000 buzz before damage

Hey guys,
I have a 77 kz 1000A1. I just had head redone, punched to a 1075. I had the ape heavy duty valve springs installed at time of rebuild. I was contemplating installing a rev limiter on the dyna-s system for extra insurance, but don't race the bike, but do like to run her through the gears from time to time. The redline is at 9,000. I don't push her past that, but am curious if a shift is missed, at what rpm will damage occur?
Thanks for the info

The limiting factor would normally be the valve springs allowing the valves to float, and spitting a shim, or tagging the exhaust valves, but you seem to have that part covered.

I would set it at 9800

The machinist who did the head on my 750 said the valves/springs were good for 10k, though I would never get near that.

The other factor is the crank. The crank is a roller bearing crank - and much over 10,000rpm the rollers stop rolling and start sliding - and that's not good...

Jeff.Saunders wrote:

The other factor is the crank. The crank is a roller bearing crank - and much over 10,000rpm the rollers stop rolling and start sliding - and that's not good...

we have a winner! if your motor stops making power at 8,000rpms it doesnt make much sense to spin it much faster than that,but thats my simplistic approach anyway! :laugh:

Plums, what do you limit your big bore motors to?

Jeff.Saunders wrote:

The other factor is the crank. The crank is a roller bearing crank - and much over 10,000rpm the rollers stop rolling and start sliding - and that's not good...

Jef;
That is interesting. Do you feel that that is the same for the Suzuki cranks too. The pro stock bikes operate from 10,000 to 13,500. You think they are just sliding the rollers on a pass?

Wonder why they don't just build those cranks with a bronze bushing instead of rollers.

Something to think about.

I have often thought I would want to take the time to figure out what the rpm of one of those rollers is at 10,000 crank speed. Same with a wheelie bar wheel at 230 mph.

DoubleDub wrote:

Plums, what do you limit your big bore motors to?

my tach cable is broke on the black 1327 ltd ,but judging from the way it was running the other night at the track and the way my pacemaker was acting id say i was shifting at around 9000 once i got myself settled down. my heart had enough entertainment ! :laugh:

Go Jim!

A 1075 with stock head can't breath enough to make power much past 8500 to begin with. Probably closeer to 8000. Not one bit of sense trying to spin it past there...

A couple of years back the PS Zuki bikes made 3.6hp/cid at about 13600rpm with a red line of 14500rpm and it took this to get there...


I don't think they'd last very long at Peak HP RPM outside of a drag race :woohoo:

i did get to see a hotrodded harley running 5.70 on the motor the same night at the track,i heard from a good source that bike runs easy 5.30s on the bottle when it hooks up. :S

PLUMMEN wrote:

i did get to see a hotrodded harley running 5.70 on the motor the same night at the track,i heard from a good source that bike runs easy 5.30s on the bottle when it hooks up. :S

Yep....there's some wicked VRods out there these days

larrycavan wrote:

Go Jim!

A 1075 with stock head can't breath enough to make power past 8500 to begin with. More like 8000. Not one bit of sense trying to spin it past there...

A couple of years back the PS Zuki bikes made 3.6hp/cid at about 13600rpm with a red line of 14500rpm and it took this to get there...

whats the life expectancy of a pro stock motor at 13,000 rpms? but of course at 6 secs a run theyre not doing it very long! :laugh: