riding past redline

The 750 Turbo, which used virtually the same bottom end as the 650, is a testament to the strength of that family of engines bottom end. The 550 is a different beast though. Again, I'm not expert on those engines but rod bearing failures were at least somewhat common. Surely one of the 550 racer guys here knows the history? Probably related to oil supply?

Oil supply is exactly why they would fail on the crank. The design of that bottom end is nearly bullet proof! I'v killed 1 650 and 2 750 bottom ends. They will spin to the moon but, past redline isn't all bad but way past isn't good. Put valve springs in it, keep lash adjusted well, get some track time and study those tickets!!! guessing first gear change will be higher in the rpm range and get lower as you go thru the gears. Like someone said, these are a but a tool to speed, you go faster, you wear things out and break shit!

Les

If you are using an OEM tachometer, it is no more accurate than the OEM speedometer. You are probably not actually running it past the redline.

My AutoMeter 5" monster tach is pretty damn close to reading true rpm's

I think the original poster is referring to a Zr550, so I don't know how relevant Kz550 HP info would be, especially without stock exhaust and intake.

I know I regularly rev the Gpz (Kz550D) past the 9500 redline, and it is still pulling past that. What else you gonna do when you're already in top gear?

loudhvx wrote: I think the original poster is referring to a Zr550, so I don't know how relevant Kz550 HP info would be, especially without stock exhaust and intake.

I know I regularly rev the Gpz (Kz550D) past the 9500 redline, and it is still pulling past that. What else you gonna do when you're already in top gear?

EXCELLENT OBSERVATION!!!

You are absolutely correct. The 550 Zephyr (ZR550) makes 49 hp at 10,000 rpm (see link below), and that is a much higher rpm than the KZ550 engine's maximum power, so the chart I posted earlier is irrelevant. Thanks for the correction! Ed

www.motorcyclespecs.co.za/model/kawasaki...asaki_zepher_550.htm

yeah, sorry, should have specified - 1990 zr550 B1.