The International CBX Owners Association

I know this may sound sacreligious but, I have a (nearly) complete 79' CBX and want to start over with a late model sport frame. Where can I go for advice on which frame works best with the least hassle for installation? I need to rebuild the carbs and get an alternator clutch that works but otherwise, I am "all there?. Thanks, Mateo

P.S. The bike is for sale on craigslist.com in Houston and will let it go soon if I don't get some useable feedback. Thanks again, bros.

If you do find a modern sportbike frame that won't be too difficult to stuff the CBX engine in, ground clearance will be a problem because the engine is considerably wider then modern engines. It'd be a lot easier to graft a modern sportbike tail section on a CBX and mount modern/wide wheels. It's not too hard to convert to a modern swingarm and monoshock either.

Welcome to the site navygas.......

May be simpler & cheaper to strengthen the existing frame with gussets & cross members & upgrade forks & swinging arm.....

I prefer installing modern swingarms on the 81/82 CBX frome. The swingarm is held on with threaded collars and it's fairly easy to machine larger holes in the collars v/s machining out the holes in the frame for a swingarm with a larger dia pivot. And for modern sportbike bodywork, cut off the subframe and weld tabs for mounting something like an early CBR900RR subframe and tail. I've installed those on two different CBX's. One of them Chris in Colorado has and he installed an RC30 upper fairing in front also. It sounds complicated but it's much easier then trying to stuff an engine in something not meant for it. The CBX engine is designed as a stressed member of the frame and there is no frame under or in front of the engine. Most modern frames wrap around the engine or have two beams going from the steering stem to the swingarm pivot area. It wouldn't be difficult to stuff a CBX engine in one but to do it to where it worked effectively is another matter.

cbxtacy wrote:I prefer installing modern swingarms on the 81/82 CBX frome. The swingarm is held on with threaded collars and it's fairly easy to machine larger holes in the collars v/s machining out the holes in the frame for a swingarm with a larger dia pivot. And for modern sportbike bodywork, cut off the subframe and weld tabs for mounting something like an early CBR900RR subframe and tail. I've installed those on two different CBX's. One of them Chris in Colorado has and he installed an RC30 upper fairing in front also. It sounds complicated but it's much easier then trying to stuff an engine in something not meant for it. The CBX engine is designed as a stressed member of the frame and there is no frame under or in front of the engine. Most modern frames wrap around the engine or have two beams going from the steering stem to the swingarm pivot area. It wouldn't be difficult to stuff a CBX engine in one but to do it to where it worked effectively is another matter.

And he (George) knows.....

CBX FRAMES - NON STOCK
I do think putting a CBX motor in a newer rolling chassis can be done and work great. Aaron and I talked about this a few times. I am also convinced it would not be that difficult if one has the fabrication, welding and technical skills to do it or knows someone that does that would help. The thought of a CBX motor in a 996 Ducati or GSR rolling chassis solves a lot of issues once done. There will be plenty of design and fabrication hurtles to overcome, but it can be done.

The second approach is to have someone build you an all new CBX frame. They are around and if you want information on this we can talk about it.

The third approach is an existing Spondon or other frame. These frames are very expensive and the designs go back to the mid 1980s. A lot has happened in motorcycle chassis and frame technology in the 20 plus years since then.

This pretty much covers the CBX non stock frame options.......I think


CBX FRAMES – USING MODIFIED OEM STOCK FRAMES
Here are some things to consider another new front and back on the CBX alternative approach

1. The CBX is one or the only bike of that era that is still used to make some of the wildest, baddest custom bikes of today. My guess is half to most of these customs still use the stock CBX frame as is or modify them.... so in my view the CBX frame is not the weak spot ...the early model forks (35mm), rear shocks, plastic swing arm bushings (79) and narrow rims/tires and other things are. Check these links below showing our ICOA member magazines in PDF to see some of these amazing custom bikes and what was done on their frames

viewtopic.php?t=3413
viewtopic.php?t=2059

2. There are all kinds of variants of new fronts and backs that can be made to or nearly bolt on the CBX....look through the photo albums on our site and above links to see for yourself. FZR1000 front and back on a CBX frame, VFR front and back on CBXs........on and on….. it has been done and as such if you can find one you like…copying the parts and mods makes it easy for you. If this is something you want to do vs putting a CBX motor in a newer bike rolling chassis you can pick the one you like best and we can put you into contact with the owner. This link will take you to the "Handling" forum where you can see if there is anything of interest there. viewforum.php?f=24#top2

3. The early model CBX frame is plenty good as is for a stock motor and hp up to 115hp or so (my view). There are those that have road raced CBX with very high hp engines …and they used modified CBX stock frames. My 80 frame as shown in the photo albums... and others are good examples of gusseted and reinforced stock frames

4. Put an 1100f front and back on an early model and most of the handling issues will be settled. There are posts, pix and articles that already exist we can help you with if this is an option. Its an econo fix and not all that trick or interesting at this stage, but it works

In the end you are doing the right thing...due diligence .....by asking the questions here on this line where people that have done it or know can supply opinions. I would follow this up with phone calls to those that reply to get even more information. If you need their contact info let me know



Keep us all posted now

Not just a pretty face Mike........

I'm with Mike and George on this one, the CBX frame is plenty strong enough for the extra ponies you desire with some simple gusseting and bracing, like George mentioned if you want better suspension its much simpler to spend the fabrication effort on grafting on late model fronts and backs.

Heres a couple pics of the bracing I did on Mikes 80 and a couple shots of a ZRX swingarm conversion I did to my 79. Mike's 80 already had some additional bracing under the tank which I think is over kill and just causes clearance problems. The stearing heads on these bikes are typical Honda over engineering and plenty strong, a few extra strap gussets would be fine.

http://www.blackstonetek.com/Inertia.htm
unsprung weight is so very critical. You can fit CBR600F2 wheels to the CBX fairly easy. They are much lighter then CBX or CB1100F wheels. None of my CBX's have the frame braced and I've never felt like I've had frame flex problems. I've concentrated more on cutting unsprung weight with light wheels/brakes then adding more steel to the frame.

Mike Barone #123 wrote:CBX FRAMES - NON STOCK
Snip/MB

The third approach is an existing Spondon or other frame. These frames are very expensive and the designs go back to the mid 1980s. A lot has happened in motorcycle chassis and frame technology in the 20 plus years since then.

Snip/MB

What I stated above is not correct related to the Spondon frames made today. See this pix Chris posted and you can see for yourself. Sorry all.

Mike