Quickie: KZ550 vs KZ440

I've tried to run a search for this question, but can't seem to find anything and this looks like a good topic to ask. My KZ400 just got fixed to the point that I can get up to the higher speeds (torn carb diaphram). What's a good cruising RPM for these little twins?

I want to make a run through the mountains and I'm not worried about that 'cause the speeds are around 40-50 mph. However, the road back down from Larimie is 65 mph and I think I'll be between 6500-7000 rpm maintaining that for about an hour. Just want to make sure I'm not asking for a blown engine.

Any thoughts?

Looks like the 440 is geared a little higher. Just the other night I noticed 65 mph turns the engine at 5800 rpm. I wouldn't run these little twins over 6000 for any prolonged period. But short runs at high speed don't hurt these at all. I was sprinting up around 9000 in third gear, but only for a moment before I up shifted a couple of gears. Like I said before kawasaki builds one hell of a small engine.

The hardest thing on these motors is idling in traffic when it is 100ºF outside. That will cause far more wear and tear than interstate speeds will. As always a well maintained bike will hold up under harder riding than one that isn't.

Post edited by: Tyler, at: 2007/05/15 11:27

Tyler wrote:

...I noticed 65 mph turns the engine at 5800 rpm.

I agree here - just yesterday I had my gf's KZ440 (82, Belt) running flat-out doing around 65~70 and I would say it was just shy of 6000 rpm.

Post edited by: eMusicMan, at: 2007/05/15 11:11

Link14: re: crusing on your KZ400 back to Larime @ 65

I have a KZ400 and have the same question, how was your experience? I can do 55/60mph at about 5500 to 6000 rpm and wonder if that is a safe "cruising speed" without causing undo engine wear?

Post edited by: kz4me, at: 2007/06/10 16:03

5000 to 5500 sounds normal. I used to get my 440 up to highway speeds with no problem. Just a few big gusts of wind made me go all over the place.

I know nothing of the kawi small twins but my old nighthawk reved about 6000 at 110-120 kmph. Never did complain. I've seen where i thrashed that thing for over an hour chasing down a friend on a 86 ninja 1000 (65-80 mph with lots of revs). And after having my zn750 i assume the kawi twins are built equally well(always was a honda man). But then again it is a twin and is ment as a commuter bike. I probably wouldn't run over 65mph for to long but because of comfort more than blowing the engine.

I usually stay off the highway on my 440 because sheer winds really knock me around like a riot, but I can keep up more than comfy with the speed.

I pulled the spacers out from under the upper triple tree which made me for comfortable for the small bike (I'm 6'2") but it also helped stabilize the bike at speed.

kz4me - haven't had a chance to make a long run on the 400...been chasing a wiring short that was blowing main fuses for about 2 weeks. Got it fixed on Saturday. Last month after I got the torn card diaphram replaced :pinch: I did a run up the by-pass and was pretty consistant at 5800 rpm for 65 mph and 6500 rpm for 75 mph.

I definitely wouldn't want to run on the highway...was getting blown all over at 75, but my mechanic thinks I should be ok running between 5000-6000 rpms for long periods.

Update - rode to Ault over lunch, about a 35 mile round trip mostly 65 mph. Went great cruising at about 5500 rpms and the bike just purred along, although it didn't like the uphill stretches alot, had to max out the throttle to try and maintain 65.

Link14 wrote:

Update - rode to Ault over lunch, about a 35 mile round trip mostly 65 mph. Went great cruising at about 5500 rpms and the bike just purred along, although it didn't like the uphill stretches alot, had to max out the throttle to try and maintain 65.

This is exactly what I've found on our 82 KZ440 LTD - holds 65~70 quite well but the inclines arent too liked. No problems at all though... still gets 60MPG too!

-Dustin

Heya,

I've only had my KZ440 a couple weeks and haven't tried to see how fast it'll go yet, but I know I can hit 60 and a bit more without feeling like it's gonna blow up. I'm riding straight stock.