The International CBX Owners Association

My engine runs so well after getting the carbs redone that the suspension is now the weakest link...head shake at 40 -50 mph (I use Dunlops and they're hardly worn) and a wallow at moderate cornering speeds. A friend suggested mounting the engine in a Kawasaki Concours or some such sport-tourer. Is that feasible? or just insane???

thx.
Ken

Ken: Besides the fact that I am a bit of a purist and like the "original" CBX, I am also an "engineer" and from that background I strongly advise against it. While I have to admit, that there is nothing wrong with customizing a CBX to your personal taste and riding preferences, modifications have their limits. There are definitely better and easier ways to improve the handling on your CBX than sticking the powerplant into a modern 'sport-tourer" frame. Remember, the original design made the CBX engine a stressed member in the frame. As such, it does not have the typical mounting configuration of a cradle type motor. Placing the engine in the right position relative to your steering neck, and front and rear wheels is contributing significantly to the handling. If you want a different frame you may have to look for a CBX specific frame from Harris
or Spondon etc. otherwise you may very well be worse off than with the stocker. Key thing here is to keep the focus on your objective: Improve handling. I have seen CBX engines in Chopper frames, but these things don't handle. They are for show.

I agree with EMS; putting the motor in a frame not intended for it is definitely not worth the risk. If you can't find a custom, specialty frame for the CBX as mentioned, you may consider upgrading just the suspension - many have installed newer model GSXR forks, etc. and have greatly improved the handling characteristics. I myself am converting a '79 over to a '99 Hayabusa front-end and rear wheel (along with some greatly appreciated input from EMS, when I get to that point) and I'll be posting pics and documentation of the changes required.

Well, I am not a "engineer", I'm just a nobody. While I agree that there are most likely better ways to make your CBX handle, I do not see anything wrong with moving the engine to another frame. As far as the engine placement in the frame being a factor, I agree. But the people who put the Suzuki, Kawasiki and other forks and swingarms alter the geometry of the chassis which can adversly effect handling not unlike putting the engine into another frame. I feel that a person that wants to make a "hybrid" CBX can and should do it, if that is what they want.
Take a look at what Stephen and Pete did with their CBXs: http://users.ev1.net/~3cbxs/cbx/convert.htm#C2
The key is to do a good job of it, what ever you do.

I do not think Honda designed the engine for big bore kits and turbos, but I have seen them all function well on the engine. For sure Honda never intended to see a CBX exposed to 160 -175 mph as many on this list have done. I recently asked the mail list about 16" wheels and found several people that run them and think the performance and handling of the bike was improved. I would think the Honda engineers are having heart attacks over this.

Again, I do think it would be easier to do like EMS and Land_Shark suggest, but I do understand the appeal of moving the engine to a different frame. If you decide to do it, keep me posted as it will be an interesting project.

Regards, Tom

Anything I've ever read on the subject seems to indicate that there was never much wrong with the whole frame/engine as a structural component. The problems were always attributed to the inadequate forks and wheel combination and the entire rear end from the swingarm pivot out. And when the bike was designed they didn't have the better knowledge of materials and technology. It makes sense that to replace the components everyone at that time had a problem with to begin with is certainly a good place to start. I would have preferred going with a 'pure' Honda setup utilizing perhaps the components from a Blackbird or what have you but came across the Hayabusa parts in a rather timely fashion. And really, the stock handling is not all that bad for a well-kept, well-adjusted model. I remember riding this same motorcycle I'm restoring, at fifteen years old (which was pretty stupid when I look back on it but a hell of a rush ) and recall it being not at all intimidating but quite agile at speed.

If you want your ProLink 81/82 to handle to the its best potential, do as I have done: modify forks w/ RaceTech gold cartridge emulators by Mike Donndilinger and Team T-Rex, Progressive rear shock, new Bridgestone Spitfire S11 tires (100/90-19 front, 130/90-18 rear) even if your tires aren't worn out, rebuild/regrease ProLink bushings and seals w/ Honda moly (this very important- slight binding causes major problems, and good maintanace anyway), do all this and you'll have the best handling and safer riding 6 cylinder around. And a very happy CBX (and owner)

NOPE,can't be done! All those bikes including the one on the front of web site are make believe. :>)

Land_Shark makes some good observations. So if we agree that the swingarm and forks are the limiting factor on a design technology 20+ years old and we then upgrade those parts, what is left to fail or be the weak piont....the frame. Also if you look at some of the CBXs modified to do road racing duty, all the frames have been gussetted and braced. Mike Barone's "dawg" is a great example. It is the best handling CBX I have ever rode. I have many e-mails about '79&'80 vs '81&'82 handling. The general consensious was (in stock form) the '80 was the best handling. If you consider modifications, the '79&'80s are better handlers (not my opinion, others who can ride much better than me). I will eventually have a '80 with a 1100F front and back. I have the parts, just no time to mess with since we are going back to Bonneville.

One thing that I thought I pointed out: The objective was to IMPROVE handling. Not building a show project. Sure, you can stick a CBX motor in another bike's stock frame. Do you improve the CBX's handling ? No! You alter the donor frame bike's engine characteristics!

Finding a suitable frame to fit a CBX engine is not a matter of picking any good handling frame, toss the stock motor and plugging in a CBX powerplant. If you want to cruise up and down the boulevard, you can do this. But Ken wanted to improve the handling of his bike.

I went back and read Ken's message and I could not find where he asked about improving the handling of his CBX. However, he did ask if it was feasible to put the CBX engine into another frame. So I thought this thread was about his question.

I really looked into this several times. I did measurements on honda hurricanes,GSXR`s,ZX-11`s and actually bought a 1200 suzuki bandit for a donor.. I`m like Tom I just didn`t or wouldn`t make time. I still may do it but I`ve been on this "like to own several of the old bikes I owned for the last 25 years kick!"....boy is that expensive and time consuming!

For anyone who's curious: a '99 Suzuki Hayabusa triple tree bolts up directly to the CBX steering stem with no modifications other than replacing the bearings (inner and outer races) with the CBX ones. I will post a pic with the entire front end assembled on my frame later. The only problem now is that the bars are far too low using the stock triple-clamp 'cover' used on the 'Busa but I'm looking into a handle-bar riser kit for it which should do the trick

I only mention this because I've seen many 'Busa front-ends on ebay; generally going for a few hundred bucks. Not a bad deal considering there are several thousand dollars in components if you were to price it all out.

Try genmar risers.....they will make you what you need.

Ken Glaser wrote:My engine runs so well after getting the carbs redone that the suspension is now the weakest link...head shake at 40 -50 mph (I use Dunlops and they're hardly worn) and a wallow at moderate cornering speeds. A friend suggested mounting the engine in a Kawasaki Concours or some such sport-tourer. Is that feasible? or just insane???

thx.
Ken

Ken, if it's a late model, increase the air pressure in the rear shock to 80 psi. You won't hurt a thing and you'll be amazed at what it does for handling. THE HINGE IS GONE.

Ken Glaser wrote:A friend suggested mounting the engine in a Kawasaki Concours or some such sport-tourer. Is that feasible? or just insane???

I'm with insane. How about a Big Red CBX???