Water cooled KZ900?

Anyone ever seen one of these before? Seems like a lot of effort to solve a problem that doesn't normally exist, but it is interesting looking.

H2O KZ

Have not seen one, but water cooled engines generally fare better than air cooled because their internal temps are better controlled and the oil isn't beaten up as severely by high temps.

The machine shop that did my head was the service center for the KZ1000 police bikes of all the local cities and the guy told me on average they ran less than about 20k miles before needing valve jobs. Got to think that's heat related.

650ed: yeah, that's fixing something that is NOT broken.

Not trying to start a fight here, but water cooling brings ailments all it's own; not superior, not inferior...simply different.

The machine shop that did my head was the service center for the KZ1000 police bikes of all the local cities and the guy told me on average they ran less than about 20k miles before needing valve jobs. Got to think that's heat related.

Actually, no. The fact that later model motorcycles need their valves adjusted less frequently is directly related to design, tolerances, and specifications. This has nothing to do with how a motor is cooled. Consider: any late model sport-bike that needs any valve adjustment, mid-80s Honda 650 Nighthawk that needs no valve adjustment. The Nighthawk isn't 'better', it just has hydraulically adjusted valves as designed by the engineers...and it's air-cooled.

Also, don't think that a liquid cooled motor necessarily has internal motor temperatures that are lower than air-cooled motors. RC51s regularly run in excess of 220+ degrees! Nothing in my garage runs that hot...on purpose:lol: . Yet, there is nothing wrong with the RC running that hot (other than operator discomfort) b/c the designers built it that way.

Most motor oils are designed to take some impressive heat. The thing that performance motorcycle oils have to worry about the most is "shear", which is extreme in most motorcycle engines b/c the crank-shaft oil is shared with the transmission oil, which is shared with the clutch oil. These are three ares where shear is extreme and an oil can be broken down rapidly. These three areas are not directly affected by liquid cooling.

In short, air-cooled motors are not inferior to liquid-cooled motors. However, technology marches on and later model designs do achieve their goals more effeciently than designs of the past...they'd better, or we're going backwards.

-KR

PS> Not trying to offend...

The machine shop guy did not tell me the KZ1000's needed valve adjustments every 20k, he said they needed the heads pulled and have the valves re done that often. When I told him my KZ-750 twin had made it about 45k on the original valves, he was stunned. he had never heard of a kawi going that long in city riding without needing to tear the head down. he thought mine was going in for it's second valve job by then.

I didn't do nearly as well the second time: the valve seals failed after about 15k miles and I had to tear it down again.

I just don't see air cooled engines doing what I see some cars do: going 150k without ever opening the engine at all except for maintenance.

No doubt water jacketing brings it's own problems to the table. Complicating the mechanics and such but keeping a steady and lower temp was always told to me to be a good thing. ie. Gold Wings, Water Buffalo's etc that had long mileage lives. Fact is most tourers do have water cooled engines (not all). Same as putting an oil cooler on. Heat will kill an engine. Todays mfg practices adds life because quality selection and fit are better than yesterdays. Tolerances are better kept and tolerance stack up is better handled. I feel that if you are looking for longevity in an engine you would do better to control heat. You might not want the added weight or complexity but those are different issues. Interesting! Why wouldn't liquid cooling affect all the oil in the bike? All the oil is circulated. No fight here either but an interesting discussion.

just don't see air cooled engines doing what I see some cars do: going 150k without ever opening the engine at all except for maintenance.

IIRC, Ronkz650 hit ~160k miles on his KZ650 without opening the motor up.

In 1981 I helped a friend swap motors on his 75 GL1000 because it was starting to burn a little oil, it only had 250k miles on it

I did have one problem. At 30,000 I had some bad oil (Arco Graphite) if anyone remembers that stuff. About a week after riding 1500 miles in 100 degree plus heat, I was riding down the highway and lost power. Found I had spun a rod bearing, so I replaced the crankshaft with used part and did first rebore and a valve job at that time. After that smooth sailing all the way to 162,000 miles on the engine. So they can last.

All that is being cooled by water is the jugs, may help some but the head is what really gets hot.

I think the fella at the machine shop is selling valve jobs, when it may have needed a valve adjustment. 15K is pretty quick for a top end, even my H-D's will make it to 60K and the BMW made 135K before it needed anything.

bountyhunter wrote:

The machine shop guy did not tell me the KZ1000's needed valve adjustments every 20k, he said they needed the heads pulled and have the valves re done that often. When I told him my KZ-750 twin had made it about 45k on the original valves, he was stunned. he had never heard of a kawi going that long in city riding without needing to tear the head down. he thought mine was going in for it's second valve job by then.

I didn't do nearly as well the second time: the valve seals failed after about 15k miles and I had to tear it down again.

I just don't see air cooled engines doing what I see some cars do: going 150k without ever opening the engine at all except for maintenance.

i have owned sum older volkswagon beetles that were heavily suped up one was turbo'd all air cooled all went better than 100k before i sold them in great running condition

Looks like someone just handmade a tank that wraps around the cylinders. Works in theory but has no internal cooling as on the newer bikes. Waste of time if you ask me. Extra weight, extra plumbing, extra headach.

If I was to make my own liquid cooled engine, I might not be a engineer but I do have the possibities of one. I would make a rib cage type structure out of fine copper or aluminum tubing that goes in between the fins of the head only and the liquid would be propelled not by a pump or maybe a pump... was thinking steam propelsion. Will have to think more! And it won't weigh as much.