Some of you probably know that I did a lot of reading, analysis, research, and computation in coming up with improved handling for my '79. I wanted to retain a vintage look with RSU forks and my boomerang wheels, but get modern suspension and braking. I'm helping a friend plan a custom CB550 project, and there have been some interesting developments since I did my CBX project, so I thought I'd share a bit about my personal experience and research for people who are interested in taking a similar path (modern performance without USD swap).
What this post & advice hinges on is one key bit of information that I got from Traxxion Dynamics: that the 39mm Showa fork used on the Pro-Link CBX's and CB1100F are very similar to the 39mm Showa forks that have been used on many different flavors of Harley for decades. Because they're so widely available there are a lot of options related to those Harley forks. And because the stock damping rod internals are so out of date, the aftermarket has stepped in with some nice replacements. I'm going to share the information I've been able to gather about the different options, decorated with my personal experience & prejudices.
There is a lot of information on the site about fitting the Pro-Link forks to a twin shock bike - this post is all about the 39mm forks because that upgrade is straightforward and there are no great options for the 35mm fork internals.
I am not claiming that every product made for 39mm Harley forks will work in the Pro-Link forks, nor am I claiming that the Harley forks are a bolt-in replacement for the CBX items. But for those who are willing to do (or pay for) the work to fit something special to their bike, I think that these could be very interesting leads. The Sportster forks come in a bunch of different lengths, and a good shop could source or modify tubes from someone like TNK in the length that works best for your application. Given that it's possible to buy almost-new Harley forks, it might end up cheaper to buy that and do more work to fit them for your application than it is to refurbish Honda forks - especially if you are also looking to do significant brake upgrades.
FORKS
1. Race Tech Cartridge Emulators
(http://racetech.com/)
Everybody's heard about these. I've used them on 2 bikes before I had my CBX, and I like them a lot. If you're on a tighter budget or committed to keeping your 35mm forks, they're a very good option. If the roads are uniformly smooth where you live/ride, then they're a great option. They do a lot to improve comfort and control by reducing brake dive without being harsh. I was never unhappy with mine - I would say that they give maybe 50-75% of the benefits of full cartridge internals at about 50% of the cost.
2. Intiminators
(http://store.ricorshocks.com/product_p/039-20-1001.htm)
This is an interesting idea - they use inertia to differentiate between the forces from road irregularities and the forces from braking. They have their fans and detractors - I find the idea interesting but I've never ridden a bike equipped with this system so I'm not going to weigh in other than to point out that this is something that bears consideration along with Race Tech cartridge Emulators. The price is similar - but unlike the RTCE's which are basically like cartridges but not quite as good, the Intiminators have a slightly different behavior. This means that some people will like them better than a full cart setup, and some will like them less. Because they're atypical, you might want to look for a chance to ride a bike with these before you go this route.
3. Traxxion Dynamics AK-20
(http://www.traxxion.com/AK-20-Axxion-Cartridge-Kit/)
Given that plenty of racers consider these an upgrade from the OEM cartridge internals on supersport bikes, they're at least 2 full notches above the emulators. I have them on my bike, and the short story is that they work very well. I would say that they compare favorably with the WP forks on my old KTM, which are generally considered better than Showa or Kayaba cartridge setups like on Japanese literbikes, but not quite as good as Ohlins. I am very happy with them. Something I consider a nice benefit of going with Traxxion is that they are the manufacturer AND installer. You can send them some sad old 39mm forks and they'll give them a complete rebuild - including brand new tubes from TNK if you need them, and stripping & powder-coating your lowers if you like. My forks showed up at my door looking brand now, and they feel like a million bucks on the bike. I unreservedly recommend this upgrade. With the other options, there are good suspension shops that can do the install & any other work your forks need, but I did like having a single source, and knowing that the installation was done exactly according to the manufacturer's standards.
4. Andreani
(http://www.andreanigroup.com/products/m ... 200+Custom)
(http://www.fastbikeindustries.com/)
I hadn't heard of this company before this week, but I have found that they're pretty popular within Italy (the Ducati and MV Agusta crowd seems to like them) and they make full cartridge internals for the Showa 39mm forks used on Harleys. The reviews I've read sound like they're very similar to the AK-20, except that they also offer preload (which I don't think is an option on the 39mm fitments for the AK-20's). The price of these vary with the fluctuating EUR/USD exchange rate - in some cases they will be cheaper than the AK-20's, in other cases more expensive. Fast Bike Industries offer installation at no extra cost.
5. Ohlins
(https://www.ohlins.com/2015/12/ohlins-l ... ock-range/)
They're here, they're here!!!
Ohlins would be the brand that needs no introduction. They're not necessarily the very best, but they are definitely the standard by which all others are measured (although of course not all Ohlins products are the same). In addition to their renowned build quality and engineering, they are known for being very well set up out of the box. And frankly, they have more chic or brand cachet than any of the other options listed here. If you install Ohlins, you never have to explain why. If I were doing this again right now, it would be a hard choice between the AK-20 and Ohlins.
BRAKES
This is only about the options if you choose to go with Harley forks. It might be possible to use these options on the Honda forks, but it would probably not be as straightforward in that case.
Harley has made 39mm Showa fork variants with both single and dual rotor setups, with rotors in diameters of 11.5", 300mm, and 13". I am expecting that most of us would want a dual front rotor. Do some research to find a suitable donor fork and have a plan before you buy anything. Rotors are widely available from names we Honda people would recognize, like EBC, Galfer, etc.
I suspect that with some care, luck, and machining, the Harley forks could be used in Honda triples with the Honda wheels, using high performance aftermarket Harley calipers and rotors. Fitting the oversized rotors and 4-piston calipers to my Honda forks required modifying the calipers themselves, and making adapters for both calipers and both rotors. I think it's likely that using the Harley-spec calipers on Harley forks would mean easier overall fitment, but that's really just a hunch. If it does work out, the overall look should be much cleaner.
1. Jaybrake
(http://www.jbrake.com/product_sections/ ... /index.asp)
I looked very hard at Jaybrake as an option before going with the Brembo calipers on my bike. Since either would have required adapters to fit on my Honda forks, and my machinist was more familiar with Brembo, I went that route, but I've remained interested in Jaybrake. They offer 4- and 6-piston calipers in a variety of finishes and detail. They appear to be well respected in the Harley world, and I think they're well worth checking out if you're going with Harley forks and want better brakes (or at least brakes without HD logos on them!). One of the things I liked was that they could be ordered with no cruiser-type logos or decorations - I think they'd look inconspicuous and mean on a CBX.
2. Performance Machine
(http://www.performancemachine.com/motor ... ipers.aspx)
PM is kind of like the combined Marchesini and Brembo of flat track racing and the Harley crowd. They've been a famous brand with highly regarded performance products for a long time in the American scene. Like Jaybrake, they offer a variety of caliper styles and fitments, including 4-, 6-, and even 8-piston calipers (but that last one is for running with a single 16" rotor on a 21" or larger front wheel) in a variety of finishes. Unlike Jaybrake, it seems that all of the options include prominent PM logos - which is good if you like that.
3. ISR
(http://www.isrbrakes.se/)
I wasn't able to really figure out their website and product offerings, but these folks are in a realm of exotica above players like Brembo and Ohlins. They make reference to some Harley applications on their website, and being more of a boutique shop, they may be able to offer solutions tailored for a given application. If you want your brakes to be worth more than your buddy's whole bike, you should probably give ISR a call.
I hope that this provides some helpful leads or pointers to some of my fellow CBX'ers! If I do go the Harley-spec route with my friend's CB build, I'll update this with more hands-on observations and results.
for doing the brain and leg work Phil.
That could just about make for a good 'short story' article for tech in a Xpress. As a post script, I can recommend the Racetech emulators. For the $$, probably the best thing a person can do. I put them into 35mm tubes on an old Suzy. Needed to have an adapter made to sit on top of the damper rod. Anyone would like a copy of the sketch, send me a note. (
) ...my upgrades don't come close to the other options suggested here but for how I ride the Z it works very well for me now...