F3 fork cartridge swap for 98 vfr

[HispanicSlammer]

This modification is actually pretty standard for upgrading VFR forks. To take the Cartridge/Fork Caps from a CBR and install them into a VFR. For a 5th Generation VFR such as my 1998 VFR the cartridge from an f3 will work, and for a VTEC the Cartridge from an F4 will work. I found a set of 96 F3 forks on Ebay that were sort of in bad shape. Tubes were bent a bit but not enough to bend the cartridges. The fork lowers also had some epoxy over a hole in the fork. I did not ask why I can only assume a collision with something.

I did not need those parts anyways just what was inside.

Here is how they arrived, unfortunately they came in a box that was the wrong size and was taped with Duct tape, one of the forks actually punctured the box and so there was some damage to the fork cap from impact with something hard.

I only paid $75 bucks for the darn things so I did not complain, but not good feedback. But delivered as stated in the auction - I know I know for those of you who know about my problems with Ebay and VFRd I have since decided to move on and not try to fight Goliath anymore, not worth it. Call me a Hypocrite if you will for using it.

The forks were missing the snap ring and the bushings and oil seal were loosely hanging out, and the epoxied fork bottom was pretty ugly. I removed the fork caps and slid the long adjustment tube out of the damping rods, removed the springs and spacers.

This is where I ran into problems, apparently the guy who sold these to me had already tried to remove the cartridges cause all the oil was gone - fine with me less mess!

However when I put my Allen wrench on the bottom of the fork to remove the bottom bolt it would just spin - I tried applying tension to the damping rod to get a bite on the screw but the bolt just continued to spin without unscrewing. I HAD TO GET MID-EVIL ON IT!!

YUP thats a hacksaw! Look at that awful epoxy job. I just cut off the lower part of the fork to gain access to the cartridge.

You see what was happening is the bolt had frozen into the compression valve body and was spinning the valve around inside the cartridge - nothing I could do but cut the thing open to get to the cartridge.

Here you can see the cartridge bottom and the bottom of the fork cut off I was careful not to damage the actual cartridge itself.

I pulled off the top of the fork body as much as I could

The fork tube will not come off until the cartridge is unscrewed there is a flange that prevents it from coming off. What I did now was maneuver the cartridge bottom onto my vise so I could clamp the compression valve and prevent it from spinning. It worked, I was going to toss the F3 compression valve anyway.

Two months ago I replaced the compression valves on my cartridge with Race Tech Gold Valves, they are the same size as the F3 valves so I just transplanted my Gold Valves into the F3 Cartridge.

Here you can see the parts I needed

The F3 cartridge, the fork cap and with the rebound adjustment rod are the parts I needed. looks almost the same as the VFR cartridge but with that adjustment rod that slides down the damping rod tube.

After removing the locking clip on the bottom of the F3 cartridge I removed the Rebound and Compression Valves.

You can see the rebound valve is a different design from the VFR valve but the compression valve is the same - no adjustment.

This is a picture of the original VFR valves notice the difference.

The F3 rebound valve has a hole that can be opened like a faucet, there is a long rod that can be moved up and down to open the hole to control the flow of oil.

Here you can see a side by side comparison of the two cartridges

The F3 is shorter but has a longer fork cap, the VFR also had a fork oil lock piece that serves as a spacer cause the forks extend longer on a VFR due to the difference in rake between the two bikes. Longer rake requires longer forks.

Here I am transplanting my Gold-valves compression into the F3 fork.

I also transplanted my Gold Rebound valves into the F3 forks. I decided to make an adjustment on the compression valve by removing one .15 x 17mm shim for a bit softer ride, the ride was still a bit harsh. Race Tech shim stacks are designed for racing and so can be a bit harsh on street applications, its just a matter of removing a shim to your liking. They actually provide a series of recipes for different shim stacks to give you a harder or softer ride - mostly its just a matter of adding a shim or taking one off from the recommended recipe.

If your not quite sure what I am talking about I wrote a more detailed description of the VFR Valves in this Thread its a more detailed reference piece with diagrams and such, refer to it if you need more info.

Intalling Race Tech Gold Valves

All the pieces side by side

The Springs side by side

I thought I might need to adjust the size of the spacers on my springs - I use Race Tech springs designed for my weight. They are stiffer than the Honda Springs and are single rate. So I put the spacers and springs side by side and they turned out to be the same length together. so I did not cut the spacers to compensate. I may still need to cut some of the spacer to get the bike to sag right but from looking at them side by side I determined that they do not need to be cut as of yet. It all depends on if the bike sags properly when I get them back on the bike. I decided to put the oil lock piece from the VFR cartridge on the bottom of the F3 cartridge. The F3 just bolted right into the compression valve.

The VFR had that lock piece in there between the compression valve and the bottom of the fork.

All put together.

It looks like the bike sits a bit high with the preload backed all the way out, I still have to measure the sag so I may still have to cut the spacers I will report on that later after I do my sag measurement.

Springs, spacers, washers, lock-tip all installed.

I also solved my oil leak by just buying a whole new oil pan. I stripped out the threads on the oil plug on the old one and tried to repair it with some metallic epoxy. Did not work! I called around to machine shops to bore it out and tap it for a larger plug. Ended up just as cheap to get a new oil pan!

Brand New Oilpan

[Guest P.O.]

Hey Slammer !!!

I'm a regular lurker on this board, but this topic is bringing me out into the light !!! ?

I've been looking at doing this swap on my 2001 for a while now... I've got some Race Tech gold valves waiting in a drawer, and will also be buying new Race Tech fork springs soon. ?Figured I might as well upgrade everything at once...

I really am no expert at suspensions, so please excuse me if these are stoopid questions...

I could get a pair of F3 forks for REAL cheap. Problem is, they're quite bent, wich means the damping rod will also be bent. ?Now I was wondering, can you swap the damping rods from the F3 for those from the VFR cartridges, or are they "cartridge specific" ie F3 damping rods only will fit in the F3 cartridge ? ?Is it even possible to break apart the cartridges more than what you did ? ?And if a swap is possible, can you retain the fork rebound adjustment ?

My goal was to take the F3 rebound valves and fork caps, use my VFR damping rods, drop in new Race Tech springs and Gold Valves. ?Somehow, I don't think this would work, but I thought I might ask...

Thanks in advance for your answers. ?BTW, your "How to" pictorials are really great !!! Keep up the good work.

Cheers,

P.O.

2001 VFR Red Devil (currently resting for a few months...)

Quebec VFR Club

[HispanicSlammer]

You cant remove the damping rod from the cartidge without tearing the cartidge apart, stamped together.  so a bent one is just bent.   Perhaps some heat to bent it strait but it might be stress cracked.

[Joe Foe from Buffalo]

I had my forks redone the easy way by Traxxion Dynamics

http://www.traxxion.com/about.shtml

With the F3 tops and my original VFR bottoms. Makes the bike ride soooo much better and feels safer in conners.

?If I was going to do it again. I would use VTR bottom forks insted of the VFR so I could easily upgrade my brakes to better ones. ?Some of the guys on the VFR websites in europe use RC51 forks brakes, tripples,wheel (intire front end) for the best results.

[Guest martincaf1]

Great post, Slammer. Obviously you've done this posting / storytelling stuff before!

Question:

With all the time and effort you guys put into upgrading your bikes, wouldn't it be more worthwhile to simply put the money towards a newer model (ie. to VTEC)?

All new adjustable suspension, great brakes, etc etc..

Just a thought.

[HispanicSlammer]

Well the VTEC is the same thing, non adjustable, overdamped less undersprung for the big guys.  The VTEC suspension is good but not as good as my Ohlins shock f3 racetech suspension is now!

[Joe Foe from Buffalo]

I have thought about a newer bike.  When I look at them though I can't find one I like as much as my 97 VFR.  Some odd way I have allways loved the 94-97's the way they look,sound,feel,ride.  I do like trying to make them even better oddly enough also.

[Guest mdr vfr]

Nice write up HS.   :bow:

[Guest Pillowsplat]

Nice post Slammer. After doing this once I see how much is involved in.

We should call you

Hack Saw Slammer  :smash:

[sa1713]

Happy New Year to all.  I searched available posts and could not find an answer for it, sorry to bother all with this newbie question.  

A few months ago I picked up an all stock 98 with 4k.  I've  changed oil/coolant/hydraulics and all this talk about forks has me wondering.  

Should I be concerned about the original oil enough to flush it?  I could not find any info in the shop manual. Is there a shelf-life or is it rather a function of miles/use?  If it needs to be changed, should I jump into the F3/gold upgrade HS did?

I'm still getting used to the machine, and have not noticed any unusual bounce/push.

Any and all suggestions are appreciated.

Jim

[sa1713]

Thanks Fixer.  One less thing I need to address before the final thaw.....

[stav800]

Just wondering Slammer, will F4i internals go in the same way on a vtec?

[Baileyrock]

:twist:  HS, the valve bodies for comp.& rebound look exactly the same for the VFR and F4, looks like you could use a rebound body on the comp. side and vise versa.

Were the Gold valve bodies the same and just have different shim pacs or what on your's ? ???

[HispanicSlammer]

I double checked on the Race Tech sight, the F3/F4/VFR use the same gold valves.  You can look up the part numbers on the race tech site.  I am not sure how the F4 adjusts for compression so that may be different.  I know the f3 I used did not have compression adjustment.  But if its like the ajustment on the rebound the valve and shim stack are a seperate componet from the ajustment mechanism.  I just swaped them out from the VFR to the F3 cartridge.  I made an adjustment to make the compression shims a bit softer but that was because I thought they were a bit harsh even before I did the swap.

For Race Tech Gold Valves Remember this, compression adjustment shim stacking is determined by the wieght of the rider Rebound stacks are determined by the spring rate only - I guess indirectly rebound it is determined by the wieght of the rider if you using a proper spring wieght for the load.

[Baileyrock]

:twist:  Thanks HS, I know they all use the same one's. My question is :where the Gold Valves (gold piece) for comp. and rebound the same ?

The stock one's of the VFR look identical as do the F4's(interchangeable) between bikes and r/c.

???

[HispanicSlammer]

Do you mean can you use a compression valve for a rebound valve??  No the rebound valve has a large teflon strip while the compression has a small o-ring (cause its is static and does not move).  If you look closer at them you will notice the difference when you look at the side profile.

[Baileyrock]

:twist:  That's why I'm asking, I don't have a Rebound Gold Valve yet just the Comp. Gold Valve.

The stock all have o-rings !

I'm wondering if I can modify (machine) the stock rebound valve close to a Gold valve. ???

[HispanicSlammer]

HMM you can see the thicker ring even on the stock rebound valve here.

border='0' alt='user posted image' />

[Baileyrock]

Do you mean can you use a compression valve for a rebound valve?? ?No the rebound valve has a large teflon strip while the compression has a small o-ring (cause its is static and does not move). ?If you look closer at them you will notice the difference when you look at the side profile.

Details,details  :goof:  Yes your right, i finnally look at the sides of them !

Thanks again HS ! :bow:

[Guest ZmZmOn2]

Great post Slammer and very timely as I was just toying with suspension re-do and am getting quite confused on options.

(Cost is also becoming a factor, baby on the way...)

To clarify: in this swap you retain the VFR lowers and just use F3 internals, gaining you compression adjustability in addition to pre-load?

Joe Foe - contact me directly or, if you want, post here about your dealings with Traxxion.  Riding friend with a FZ1 just used them and gave me the bug to do this.  Like to hear what it set you back $$$ wise if I don't want to pursue the DIY route.  Did Traxxion find the F3 parts for you?

Thanks!

suttonbk@comcast.net

[Joe Foe from Buffalo]

I'm very happy with Traxxion and what they did for my 97.  It made me wonder why the heck I din't do it long ago since it made the bike feel soooooooooo much better.  They really do know how to do it.  As for how much it set me back.   I don't recall honestly around $1,000 maybe.  I just gave my card # and never looked back.  I tried to get discounts and they only offerd a slight one.  I found my own F3 Forks and sent them compleat with my 97 forks and they did all the work.  I only had to tell them how I ride,the kind of roads I ride on and how much I tip the scales at. If you have not done the rear shock yet...do it ASAP.  It all so makes the biek feel soooooO much better.

[HispanicSlammer]

I had a warm day today so I shoed on a new set of Pilot Roads and set my sag.  I had the preload backed pretty much all the way out and the forks only sagged 30mm.  So I put a jack under the header and screwed off the fork caps till lowered it a bit to take off the cap.  Pulled out the spacers and cut off about 8mm of each one. Put them back in and reset my sag.  Now I have a bit more adjustment on my preload to work with.  Sagging about 35mm up front and 32 in back with the preload showing 3 of 6 lines.

[Guest ZmZmOn2]

Still in a major dilema.  Following this thread and the one where everyone is going the Hyperpro route.  

I spoke with Traxxion and they were helpful, but fall into the fixed rate school of thought on springs.

Preliminary research for F3 forks looks they run $300-$400 for a servicable set.  Is this about right?  Was anybody able to find a much better deal?

[johnalex]

Thanks for the write-up and pics. Did this to my 98 a couple of years ago and have never looked back.

John in Calif

[HispanicSlammer]

Still in a major dilema. ?Following this thread and the one where everyone is going the Hyperpro route. ?

I spoke with Traxxion and they were helpful, but fall into the fixed rate school of thought on springs.

Preliminary research for F3 forks looks they run $300-$400 for a servicable set. ?Is this about right? ?Was anybody able to find a much better deal?

To give you a bit of reasoning why the suspension gurus are using fixed rate springs when there are progressive rate springs on the market has to do with the way the damping is valved.

For example take a look at the stock valves, the tiny holes compared with the Race Tech or Traxxion valves.  You will notice they are much larger and allow much more oil to flow than the stock valves.  The damping action is done mostly by the shim stack, rather than being limited by the size of a smaller valve hole like in the stock cartridge.

So what does that have to do with springs?  Stock setup uses heavy oil, smaller more constant vavled holes, but compensates with a progressivly wound spring.  This allows for a decent riding fork for a very wide range of riders.  The bike is undersprung for the most part till you reach the limit of the stroke where the progressively longer windings take more energy to compress, combine that with a heavy oil small vavling and a decent airpocket to act as a seperate air spring you can accomidate a wide range of load and still have a fairly predictable ride.

Where as the aftermarket guys use stonger springs for the most part, single rate cause the shim stack is progressive instead.  You have to consider the entire fork as a whole system rather than a sum of its parts.  Two different ways to engineer damping systems accomidating different load conditions different ways.  

The aftermarket system is more sensitive to weight load but provides a much more compliant ride over a variety of road conditions - where as the stock system can accomidate a wider range of loads but offers less compliance over differnt road conditions.  

I changed to stiffer springs over a year ago before I installed new vavling and found I did not wallow as much in the tight stuff, however my ride was pretty harsh.  I compensated by going to 5w oil rather than the 10w standard and found I had a bit better ride, compression was much better but the rebound was just wrong cause thats dependant on the spring rate.  It was fine over smooth roads but bumpy roads would have me rolling off, seemed like a good trade off for not wallowing in the tight turns, I just had to roll off when it got bumpy.

Now that I have the right valving BOY its so much better, bumpy roads seem to be soaked up much better, I still get some shock on the really bumpy stuff but no nearly as unstable as before,  I feel like it does not fight me so much to lean over either.

If your going to keep the stock cartridge the way it is a bit stiffer progressive spring may solve your wallowing issues.  If you go for single rate springs then I would recommend a complete vavle job as well to match them.