Oberon Signs
Janne Desir
After much hesitation, I purchased and installed an Oberon slave cylinder for my '98 5th gen. It costed over 200 euros including purchase, shipping, customs fees and installation. I was expecting a decent improvement, but as soon as i picked up the bike from the workshop, the disappointment was almost total.
The load required to operate the clutch has decreased by 10% - 15% in my opinion. Not more. Pretty much a negligible gain. The only advantage is that the lever is smoother, but that probably comes from the fact that the old slave was 25 years and 75,000 km old. The effort to pull the clutch is almost the same.
I am so disappointed that I would be tempted to take it apart and resell it, but it would not be worth it.
The most irritating thing is that the point of engagement has remained almost the same, a sign that the leverage ratio has not changed much.
In my opinion it could have been increased slightly (there is still a lot of travel) but evidently in the design phase the leverage ratio was not increased further to avoid problems.
Surely my rhizarthrosis is quite demanding, but ultimately a bigger slave is useful only in combination with other interventions (clutch springs, clutch lever, master cylinder, physiotherapy, etc.).
Not that it's useless, but I don't agree with the people that review it as a definitive solution. Probably it's a decent gain for their needs, but not for me. Just my 2 cents.
IMHO that is a bit insensitive Mohawk. The op asked for advice about a cost effective potential solution to a problem they experience. That you find the stock clutch feel fine is irrelevant. I'm sorry cuoccoimix that I do not have an answer for you. Perhaps others will know more. My only uninformed thought revolves around clutch springs but I have no idea if that has any merit.
I just noted your hand issue, so understand the reason for the requirement now. The only solution would be a change of Master Cylinder or change to a semi automatic system where the actual lever is just a control for an electro hydraulic actuator. Not seen one but it could be rigged up, its a short throw fairly light pressure system. Hope you find a working solution.
What could be an adaptable master cylinder? I would prefer something that doesn't alter the look of the bike, possibly from other old Hondas.
Something that allows me to take advantage of almost all the travel of the lever, without compromising its functioning.
Travel is not important. I just need a lighter action on the lever. A lighter clutch needs a wider range of leverage though. So i need something with a long travel (more leverage) but still able to disengage the clutch safely.
Found an article about slip/assist clutch (not a slipper clutch) which might be of interest. However, while it says that it enables a lighter clutch action, no actual stats are provided and I've no idea whether anyone makes a product that would fit a VFR.
Next, adapt your bike to you. Adjust your body position and controls to make them as ergonomic as possible. This may require exercise to strengthen yourself, and making minor modifications like trimming locator tabs so controls can be repositioned on the bars.
Have you changed the clutch line to stainless, or still the original rubber hose? The original hose will be quite broken down by now, and expands under pressure, robbing force that should be directly transferred to the slave piston from the master piston. Upgrading this part to stainless will not reduce the force by a large amount, but the more efficient fluid transfer will be noticeable and can reduce the amount of work required by your hand.
You have a new slave cylinder installed now, so there's no point in asking if your oem slave is/was in good order. However, it's worth noting that the age of seals and corrosion inside the slave can affect its performance.
The clutch engagement/disengagement zone is quite small. It does not take much movement to cause slipping and disengagement, s omaking sure your system is working properly and efficiently makes a big difference.
I am using a Brembo RCS master cylinder, ss line, and larger model Oberon slave to combat the 99lb springs I had to install to prevent clutch slipping after isntalling a supercharger and greatly increasing the bike's power. Even with the massively heavier springs, my clutch pull feels lighter than stock. Not feather light, but lighter for sure. The Brembo is not an aesthetic match for the oem masters... so I installed another one on the brake side ?
Thank you for the wise and balanced suggestions. Yeah, i have thought to various solutions for driving position. But i discarded them all for various reasons. Variobars are damn expensive. ABM kits are practical but aesthetically horrible from my point of view (i hate tubular handlebars on VFR). Spacers/risers under the original clipons are almost useless. I did not trim the locator tabs because more "open" clipons would paradoxically make the position heavier on the front.
About the clutch, master cylinder was serviced one year ago with new gaskets and everything. Still has some squeaking noise though - not very sure if the workshop did a good job, also because i replaced clutch plates 2 years ago (with spring spacers that i will remove) and now they slip again in 6th gear. So there is still some work to do. Braided line is also a good advice. Sure there are still lot of things to do, but the basic fact is that the Oberon slave alone is not resolutive, and with a negligible difference other things being equal. Mine is CLU-3038 specific for my bike.
First thing to do will be to fix the slipping problem, so i will remove the useless preloader spacers installed on the original clutch springs. And then....well, i will try with more cortisone and more hyaluronic acid!
The title of your post caught my attention as I just received an Oberon slave cylinder for may 5th gen. I bought new seals to rebuild the stock one, but when I got it apart I didn't like the condition of the piston so I went aftermarket. I measured both cylinders and the area of the Oberon piston is 13% larger, so your assessment of the effort decrease is bang on. They are constrained by the housing size as far as making it much larger in diameter. I do not know of any master cylinders that would work, maybe try looking on Ebay and see if you can read the diameter off the pictures posted by sellers.
The VFR is stock with a " (12.7mm) master and 35.75 (measured) slave. The oberon slave is 38mm. You can get an idea of what is available on potential donor bikes by looking at the Brembo spares offered here: -clutch-master-cylinders/
I have changed bars to eliminate numbness on my Yamaha RZ350 and used Convertibars , which I was very happy with and am planning to buy for my VFR. They are not cheap, but if it makes riding enjoyable again it is money well spent.
I have recently had hip surgery and am looking forward to riding in comfort again this year, being in pain due to the riding position really takes away from the enjoyment of it, I wish you the best in your pursuit of riding comfort. Please share your results.
Re: locator tabs - I meant the tabs for the positions of the switch pods and master cylinders on the bars. Most people end up with wrists bent upwards as they lean forward and rest on the bars. This can have a negative influence on your comfort. Controls can (and imo, should) be rotated to accommodate your wrists being straight, in line with your arms.
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