Kawasaki X99

[wayne]

I've copied these photos from a Facebook thread. It wasn't credited to any source. I've only seen one or two grainy old photos of this bike from back in the day. However, have a look at these. These are modern photos and I suspect taken by a photo journalist. I would bet they were for an article or a book somewhere in the world. This bike obviously still exists and has been dragged out of some museum or storage facility.

This information has been taken directly from the Facebook post:

"Development of the Kawasaki X-99 prototype started in 1974. In the midst of the 1975 oil crisis, development was put on hold. The 896.8 cm3 engine featured a liquid cooled housing, 2 rotors, cross-port intake and a 5 speed transmission. When the project was officially halted, the engine had achieved a max power of 87.8 PS and a max torque of 10.78 kgf-m."

So that converts to 86.6 hp, not bad but not as much as I'd expect from a 900 cc twin rotor. I wonder if that capacity claim is correct. A lot bigger than either the RE5 or the Yamaha. The size of the rotor casings seem to indicate it may be right. Perhaps a bit low on the power as it was still prototypical?

[jm0406]

Wayne,
Interesting find. I know the man who runs the Kawasaki Museum here at the Southern California headquarters. I will ask him if he knows anything about this bike.
Jeff

[don07tncav]

Great photos and find Wayne. Is it me or does the engine look fake??

[ap951]

that's a first for me.
I've read about this bike however I've never seen a picture.
Thank you for the education Wayne, nice find

[wayne]

Jul 7, 2019 15:13:30 GMT -5 don07tncav said:

Great photos and find Wayne. Is it me or does the engine look fake??

It looks a bit odd for a Japanese bike but it was a prototype. I had a really close look at the pics. The engine has that raw casting look you see on the unpolished bits of Jap engines of the day. I think it's fair dinkum as we say down here.

Check out the oil (?) tank above the rear mudguard.

[jm0406]

Spoke to my contact at Kawasaki. He said they had nothing like that in the US collection, but when he was touring the factory in Japan, he was in a large room full of 1 off prototypes. He will inquire with his counterpart in Japan to see what he knows.
Jeff

[kanonkopdrinker]

I am pretty certain that the earlier photos of the X99 did not have Kawasaki tank badges; these seem to be a later addition.

That, and the crispness of the images make me think that these are very recent shots.

I was planning to plagiarise them in the Rotary Club’s newsletter.

David

[jm0406]

Looks like an H2 frame with a European rear fender setup. Photo does look crisp.
Jeff

[wayne]

Very interesting chat with one of the Kawasaki X99 design team. It really opens your eyes to rotary engine design.

Amazing that this bike has been hidden for so long and is now finally "coming out".

[grosours]

Hi,

this video is interresting too. And one can find some RE5 parts on the prototype...

:

Regards

[timpa136]

Thanks, all that investigative work is most interesting, what a well kept secret although it was believed many manufacturers were

interested and/or involved in their own rotary experimentation. My take away from this interview is that Suzuki solved the

"Devils chatter marks" with their patent seals and the CEM coating.

Looks like a side stand extension just like Suzuki. 

[gregt1]

its a 1975 Z1b frame,front end,wheels,hubs,brakes,instruments,A4 shocks,A4 tailight,...just my opion

[goandy]

Sept 27, 2019 20:37:45 GMT -5 timpa136 said:

My take away from this interview is that Suzuki solved the

"Devils chatter marks" with their patent seals and the CEM coating.

 

Tim, I can tell you from personal experience that they didn't solve the chatter issue. Both of my proper units had chatter marks inside them when I rebuilt them. In some areas there were actually flat portions of the housing surface with little angles between them- especially over the humps. I managed to reprofile the housings using a silicone carbide stone and they came out beautifully smooth. There was also greater wear in the centre of the housings from the main part of the apex seals- there was a ridge running around both edges where the corner pieces run. That was another reason for reprofiling the housings.

Mazda have also never fully solved the chatter marks either. I've had a few RX8 housings now which have all had chatter marks in them!

[timpa136]

Andy I stand corrected. In school the instructors cautioned against porting as they didn't know if doing so would allow the coating to chip

and you proved them wrong. From memory they also cautioned about overreving over 6800 as it only allowed for excessive seal wear.

Listening to the videos, Kawasaki started late in the rotary research.

[goandy]

Tim- you have a huge wealth of knowledge and I am always cautious about contradicting what you know! I think chatter is something you just have to live with in a rotary engine. It may take quite some time but almost always appears. Bear in mind that my motors had done a fair amount of k's and the apex seals were just about at their wear limits. The ceramic coating had certainly worn down but hadn't gone through to the aluminium.

I ported the intake and exhaust ports on mine purely because they were so nasty- not for performance! I didn't break through the coating as far as I could tell.

I wouldn't be afraid to do some more extensive porting but there's simply no need- if I want power I don't think I'd choose the RE5! I reserve the right to change my mind though...

I firmly believe that we can weld, machine and nikasil plate our housings if we need to- although honing the coated surface may be an issue depending on the willingness and know-how of the coating company. They did try to do it to Mazda housings years ago but it wasn't terribly successful. Wonder if it was because they were coating onto the steel sleeve in an aluminium housing- we don't have that problem.