View Full Version : CBR600F3 fork internals in SV forks?
sixstring
25-10-09, 02:15 PM
Hi all,
Just been reading about transplanting the cartridges from a cbr600 into standard sv forks. Sounds like a simple, cheap way to improve the sv forks. Can anyone confirm if this is:
a) possible
b) sensible
c) more hassle than it's worth
Many apologies if this has been covered in the past.
yorkie_chris
26-10-09, 01:23 PM
Good mod by all accounts. You can then valve those to work near as damnit to a properly sorted GSXR setup.
But, I've not done it myself. Have a google-fu and see what you can find :-D
plowsie
26-10-09, 01:59 PM
Have a word with Mister-C, he was doing something along those lines :)
taxonomy
05-11-09, 04:42 PM
I am in the middle of doing this fork swap, but am in the United States.
It seems to be going pretty well so far. I have pretty high expectations for it. The valving in the CBR forks is supposed to be excellent. I am having a tuner restack the shims and going to heavier springs.
In the main, the forks go together easily. Both the forks are Showa, so everything slides right together. This will allow clipons above the triples, which is what I've wanted for riding position.
I'd rather not do the whole GSXR front end swap, as don't think I need or want forks that massive. 41mm conventional forks do me fine. Also, one doesn't need to deal with speedometer mods, front wheel swaps, fenders and the like.
The forks these are replacing are gen1 forks with Race Tech internals.
yorkie_chris
05-11-09, 04:43 PM
Are they 20mm cartridges in F3?
You know anything about the valving in them? Could you post up (or PM) what stack is going into valves?
I can see the advantage of not swapping wheels and messing with speedo etc. but GSXR brakes are still superior.
taxonomy
05-11-09, 06:12 PM
I'm not doing the actual valving. Someone else is. The external diameter of the cartridges looks to me about 20mm.
The CBR internals are a common swap on VF Honda Interceptors. Jamie Daugherty does quite a few of these, being the reigning expert on VF suspension. Therefore I am giving the forks to him to do the work, as he's done a lot of these CBR600F3/something else Frankenstein forks.
What I have done this far is taken apart an SV fork and a CBR fork. I suppose I could just put them back together and guess that the valving will be OK. From the racers I know that have used CBR fork internals they have really excellent valves and the damping should be close enough, but since I had them apart... and it's November in New England.... I thought I'd send them out for an expert to look at.
The CBR internals are also a common swap for some modern Triumphs and, I think, the Versys and the Honda Hawk (http://www.hawkworks.net/tips/F3forks/F3forks.html). The Hawk guide is pretty much the same for doing the swap on the SV. I haven't found really great information anyplace on the web but it's plain as day when you take them apart as to to how they should go back together. If you are at all mechancial you should be able to do this.
F3s are getting pretty long in the tooth, so you could pick up a set cheap, this is a whole lot cheaper than doing any other real surgery to the bike besides Race Tech emulators, which actually work pretty good.
This swap will add both rebound adjustment and preload adjustment to the fork in one move, along with true cartridge damping.
yorkie_chris
05-11-09, 06:14 PM
So do you use caps from CBR in the SV stanchions?
On 1st gen bike you just use inner tubes from F3 and mate them with outer sv legs.
taxonomy
05-11-09, 10:34 PM
On 1st gen bike you just use inner tubes from F3 and mate them with outer sv legs.
Correct,
in another way of saying this, you pretty much just use the SV650 lower legs, oil seal, dust wiper and outer bushing.
You use the CBR caps, internals, inner legs/uppers and inner bushing.
The link, above, to the Hawk site has a pretty clear diagram from what to use from each fork. It works the same with the SV as it does with the Hawk. The only caveat is that I'd say to use SV seals and upper bushing, but this would be clear if you were looking at the fork. It's an easy fit.
It seems like a good mod to me, since it allows me to use clip ons which can be adjusted for both height and angle, and allows me to have better damping than I otherwise would. I'm also lucky to have someone like Jamie that really is a specialist in damping curves for these forks, but I think the CBR guts are pretty good.
He said that it wasn't worth upgrading Showa three port pistons to Race Tech Gold Valves in the CBR fork because the piston design was so good. Personally, since I am not hauling my SV down from 160 MPH before diving into corners I don't think I need upside down forks. Plus, it's something a little diffrent that doesn't scream out squid like that GSXR front ends kind of do.
yorkie_chris
05-11-09, 10:50 PM
Those big port showas are similar to gold valve. Some even say gold valve flows too well, but I'm not sure I get that.
Depends which type of piston it is. Look familiar?
http://www.peterverdonedesigns.com/images/content/motorcycle/select%20valves.jpg
that doesn't scream out squid like that GSXR front ends kind of do.
:kiss:
He said that it wasn't worth upgrading Showa three port pistons to Race Tech Gold Valves in the CBR fork because the piston design was so good.
He is right, 3 port high flow are good pistons, you just need to revalve it. It is old set up and pretty light on valving.
taxonomy
06-11-09, 12:06 AM
Those big port showas are similar to gold valve. Some even say gold valve flows too well, but I'm not sure I get that.
Depends which type of piston it is. Look familiar?
Since I am not taking the cartridge apart I can't say. I haven't seen the piston.
Anyhow, for anyone thinking of doing this mod, I would say go ahead and do it. In the end it won't cost much more than a Race tech fork, and you'll have some thing adjustable and unique. By all accounts, people that know, say the fork internals are a pretty good starting point as is. Much better than the stock SV, potentially better than an SV fork with Race Tech Emulators fork if setup right.
With the clip ons above the triples you come pretty close to the N riding position I'll be using stock S model clipons with it instead of regular bars. The adjusters would conflict with the bars, since the forks are about 40mm longer when converted to CBR internals.
Sorry to bump this old thread, but does anyone know if you can fit the Honda F3 fork tubes and cartridges into 2nd Gen/Pointy fork lowers?
taxonomy
28-09-10, 02:10 PM
If the forks are the same diameter (41MM) it should work. I have them in my Gen1. As long as the damper rod is held to the bottom of the fork with a bolt you should be able to get it to work.
It was not that complicated to make it a go, but it did take fiddling.
Thanks, sounds like it should work; pointy forks are 41mm same as curvy, and damper rod is held in by a single bolt.
Sorry to bump this old thread, but does anyone know if you can fit the Honda F3 fork tubes and cartridges into 2nd Gen/Pointy fork lowers?
You don't even need F3 tubes, you can use both inner and outer from sv. You just need to shorten rod.
I was wondering if I could use the longer F3 fork tubes and put the clip ons above the top yoke for a bit of touring next year - is this possible?
Not sure you will have enough length for clipons above.
Fatboy SV
22-11-10, 12:22 AM
Why not just fit the entire F3 legs?
Why not just fit the entire F3 legs?
Because then you'd need the Honda spindle which may not fit the SV wheel (anyone know?). Even if it did you'd have to sort out the speedo drive and caliper mounting issues as I doubt the CBR has exactly the same disc size and spacing as the SV. Or you could use the CBR front wheel and have non-matching front and rear wheels I suppose, but still leaves the speedo to fix and the CBR front mudguard to paint to match the rest of the bike. Just a lot of work.
Had intended to fit cbr600f3 fork cartridges but do not know how the cbr compression valving will work without the adjuster that is located in the cbr lower leg.
I thought the F3 only had rebound adjustment which is located on the top with the preload adjuster?
Could someone confirm that cbr600f3 only has rebound adjustment, this is the question for which I have been unable to find an answer. Believe earlier f2 system had rebound adjusters that also affected compression. Don't know exactly what f3 has.
Searching shows that only adjustable rebound damping and preload is ever mentioned with regard to these forks. This makes sense as the SV isn't the only bike which the F3 fork is popular for a 'hybrid'; the Triumph Bonnie also uses 41mm Showa forks which can have the F3 cartridges and stanchions fitted.
Stonesie
11-04-11, 06:14 PM
The more I look into this the more confused I get, there's so many options out there. I've seen it mentioned that the cartridges ect from a GSXR 600 (01 - 03) fit straight into the SV forks...
With mine I'm not really keen on the idea of replacing my 11k mile stansions with something much older, but after a progressive rideout yesterday I think I need to do something to improve this bike, or change it.
The cartridge emulators do a very good job. If you know someone local with a lathe it's very easy to make some spacers to allow the inexpensive Racetech emulator clones to fit in the pointy. I fitted them to my dads Curvy (drop in fit, no mods), my pointy (requires some spacers made) and my GPZ500 (gold valves needed a bit of machining). Along with heavier springs and new oil it's greatly improved all of them.
I wouldnt have thought K1-K3 GSXR cartridges would be a straightforward conversion as they definately have a compression adjuster on the bottom of the forks.
yorkie_chris
11-04-11, 08:10 PM
There are things you need to do to get valves that work with no adjuster to work without or vice versa. There are also a few ways to give comp adjustment if you want it.
I'm a few weeks away* from offering cartridge forks with various levels of adjustment in stock forks in minitwin legal (or not, depending on your preference for trick caps) form.
There is no way a 600K1 cartridge fits straight in to SV forks. I've got one sat on workbench (the other one is a bit stoke on trent, that takes some doing, 10 points Mr Hindle!!) and while possible it won't "drop in".
*Yes I know I said this in October, but I REALLY mean it this time!
Stonesie
11-04-11, 08:31 PM
After more digging, I found a link to these
https://www.debrix.com/ProductDetails.asp?ProductCode=24-0361-VT
Any good YC?
I think I need to improve as a rider as I'm still a newbie but the bike feels like its saying "thats enough of that fella" on the bumpy bits... If that makes any sense.
yorkie_chris
11-04-11, 08:44 PM
Yeah I have a set of these on bench right now too, just made some adaptors to fit those to a guy on here's forks. I can easily make some more.
My impression is they are same parts as racetech emulators, no difference worth mentioning.
For money an excellent mod. Cartridges are technically better but more cash.
vBulletin® , Copyright ©2000-2025, Jelsoft Enterprises Ltd.