I just bought a 1983 KZ550 A, and on the ride home it seemed to be spinning WAY too fast. Something like 4500 RPM at an indicated 65. Seems that the speedo was also reading about 10 MPH high.

Has the previous owner swapped out gears on one or both ends of the chain drive?

Any advice or thoughts would be great.

Tanx,
Doug

 

Welcome Doug To K.F.
Sorry I cant help. But, soon other members will be around and should be able to help you out.

 

Welcome to KF.

What tooth count are the sprockets that you have on the ride right now? Compare that to the manual or the fiche for your ride. Enjoy the ride and congrats

 

4,500 at an indicated 65 in top sounds reasonable. Take it for granted that all bike speedos and all non-US car speedos read high by about 7%. Some read higher than that.

Rob

 

I agree with Rob, the rpm sounds about right. You are talking about a smaller motor that is going to need to increase rpm to maintain a more elevated speed. As for the speedo, lots of bikes run 7 to 10% off.

 

That's LOW! My 550 Zephyr is doing about 5000 at 60 and I raised it one tooth on the front sprocket. That's really about normal for a 550. Keeps you in the good part of the powerband when you're doing 55-65 mph. Anything below about 3500 is close to the bottom of the power and lugging too much.

The fact is I drop THREE gears in the 6 speed to third gear when I want to really pass someone quickly and I'm doing about 50 mph. I'm catching a gear around their driver door and hitting fifth when I start to pull in, coasting down to hit 6th. In other words it's normal to rev them harder the smaller the displacement. Even my old Nighthawk S 700 ran about 4400 at 60. It's all about quick acceleration in that range.

The higher revs really won't hurt a thing either, the piston speed of the shorter stroke isn't that high compared to some of the longer stroke bigger displacement or twin cylinder machines, so it's less stressful.

Just enjoy the ability to wring out the engine more than you could a big inch engine. I certainly do. That's why I went with the 550. I enjoy being able to rev the engine and still not be so fast as to risk points on my license. It's just a rush to do so.