Firestorm Fork Conversion On 4th Gen... What Exactly Do I Need?

[Guest YorkshireWhippet]

Hello All... and calling on your collective wisdom

After owning a VFR800 some years ago I now find myself drawn back into the fold and have acquired a dark blue VFR750FV.

One of the things I want to improve is the braking and feel from the front end. Having scoured this forum and others I realise that the way to go is to convert to Firestorm (vtr1000) forks and to this end I've managed to pick up a pair - although they do have bent stantions! I'm not in any particular rush to do the job but realise that I obviously need firestorm calipers or CBR 929/ 954 ones (are they the same?) along with a new master cylinder - presumably from the same bikes, although I believe I could use one off a VFR800 (all years, vtec, non vtec?) I might even want to swap the clutch side over at some point as well just for asthetics. I believe I will also need a firestorm mudguard, but I'm confused as to whether or not I will need a firestorm spindle - some posts seem to make reference to this and others don't mention it?

At the moment I intend to get the forks sorted over the winter. I'm thinking of getting new stantions and having them gold nitrided and then getting the fork sliders powder coated in black. I don't know what the state of the internals are on the bent forks yet but presumably the damper rods will be bent as well and the fork springs may well be kaputt - although I'd probably want to upgrade these anyway.

Another interim possibilty is just swapping the sliders over from the firestorm forks onto my existing 750 fork stantions - is this feasable and what would be involved in doing this? Are there any other parts than the sliders from the firestorm that would need to be transferred. If I initially went this way I'd gain the better brakes but would I gain more adjustability on the forks or would the whole firestorm fork be required?

Thankyou in advance and hope these ramblings make sense

Rob

[thx1139]

VTR1000 fork slides right into VFR750 triples. Spacing of the 41mm tubes is the same.

VTR tubes are shorter than VFR, by less than 10mm IIRC. Since it is commonplace to lower the VFR triples on the tubes to quicken handling, no issue there really.

VTR axle is slightly longer than VFR, because VTR has 2 pinch bolts per side vs 1 for VFR.

VFR fender does not match mounts on VTR sliders.

VTR sliders will swap directly onto a VFR fork. This forgoes the gain of rebound adjusters however. Another option is using the VTR sliders/reb-adjustable cartridges/caps inside VFR tubes. To get adjustable rebound on my '96 I swapped to VTR cartridges inside my stock VFR tubes and sliders.

VTR1000 4pot calipers are the same as CBR900RR. Naturally, either bolts on. 929/954/CBR600F4/CBR600RR (non radial mount) use a newer, larger design that does match up with the mounts on a VTR slider; although there is minor interference between caliper/slider that may require grinding.

Beware: 929/954/CBR600F4/CBR600RR/RC51 calipers fall in 2 categories, early or late. Honda altered bore sizes between the two. They are indistinguishable without measuring the diameter of the pistons. Take care to get a master cylinder appropriate for the calipers you choose.

Certain GSXR1000s had 6pot Tokico calipers that will fit on VTR forks.

You may wish to maintain an integral reservoir-style M/C like what is on your VFR now. For the early calipers use a 600F4 M/C; With later clamps use 600RR.

CBR M/Cs are black. Repaint silver to match, or use a black clutch M/C from VFR800.

Like the stock VFR750 fork, VTR1000 forks are valved relatively lightly. My '96 VFR cartridges used Showa 3-port valves. The '00 VTR carts used 4port HMAS valves. Whatever your preference, a slider swap presents good opportunity to re-spring/revalve the carts. Factory and aftermarket valves are interchangeable between both forks.

[Beck]

VTR1000 fork slides right into VFR750 triples. Spacing of the 41mm tubes is the same.

VTR tubes are shorter than VFR, by less than 10mm IIRC. Since it is commonplace to lower the VFR triples on the tubes to quicken handling, no issue there really.

VTR axle is slightly longer than VFR, because VTR has 2 pinch bolts per side vs 1 for VFR.

VFR fender does not match mounts on VTR sliders.

VTR sliders will swap directly onto a VFR fork. This forgoes the gain of rebound adjusters however. Another option is using the VTR sliders/reb-adjustable cartridges/caps inside VFR tubes. To get adjustable rebound on my '96 I swapped to VTR cartridges inside my stock VFR tubes and sliders.

VTR1000 4pot calipers are the same as CBR900RR. Naturally, either bolts on. 929/954/CBR600F4/CBR600RR (non radial mount) use a newer, larger design that does match up with the mounts on a VTR slider; although there is minor interference between caliper/slider that may require grinding.

Beware: 929/954/CBR600F4/CBR600RR/RC51 calipers fall in 2 categories, early or late. Honda altered bore sizes between the two. They are indistinguishable without measuring the diameter of the pistons. Take care to get a master cylinder appropriate for the calipers you choose.

Certain GSXR1000s had 6pot Tokico calipers that will fit on VTR forks.

You may wish to maintain an integral reservoir-style M/C like what is on your VFR now. For the early calipers use a 600F4 M/C; With later clamps use 600RR.

CBR M/Cs are black. Repaint silver to match, or use a black clutch M/C from VFR800.

Like the stock VFR750 fork, VTR1000 forks are valved relatively lightly. My '96 VFR cartridges used Showa 3-port valves. The '00 VTR carts used 4port HMAS valves. Whatever your preference, a slider swap presents good opportunity to re-spring/revalve the carts. Factory and aftermarket valves are interchangeable between both forks.

Sorry but this is a bit OT, but I've been trying to find out in this forum if a fork brace for a VTR1000 will fit a 4th gen. You mentioned that the fork tube spacing is the same with the 94-97 VFRs and the VTR 1000?

That means that a VTR fork brace would most likely work with a 4th gen VFR 750 fork. Can you confirm this further if you have any measurements for the stock VTR1000 fork assembly in mm handy?

For reference, the 4th gen VFR 750's fork tube spacing is at 192mm center to center, and the fork tube diameter, where it thickens at the fork seals (where the fork brace would clamp around), minus the plastic fork protector, is at 63mm diameter.

Tried to get confirmation from Superbrace if they are the same, but unfortunately they just forgot about me and never emailed me the answer.

Maybe YorkshireWhippet can also use a fork brace on his upgrade project. As most of us already know, there is no available fork brace for the 3rd and 4th gens, but there are still braces available for the VTR1000 (Firestorm in Europe).

TIA

Beck

95 VFR - still looking for a fork brace.

[SAFE-T]

I'd always heard the VTR's forks sucked.

[thx1139]

For reference, the 4th gen VFR 750's fork tube spacing is at 192mm center to center, and the fork tube diameter, where it thickens at the fork seals (where the fork brace would clamp around), minus the plastic fork protector, is at 63mm diameter...

At the moment I don't have a VTR slider handy to measure.

99% certain the plastic fork protectors that snap over the top of VTR, '96 VFR, and CBR600F3 sliders are all the same Honda part.

[Beck]

For reference, the 4th gen VFR 750's fork tube spacing is at 192mm center to center, and the fork tube diameter, where it thickens at the fork seals (where the fork brace would clamp around), minus the plastic fork protector, is at 63mm diameter...

At the moment I don't have a VTR slider handy to measure.

99% certain the plastic fork protectors that snap over the top of VTR, '96 VFR, and CBR600F3 sliders are all the same Honda part.

Thank you Thx1139!

I guess I'm now 50% sure now that the fork dimensions are the same between the two bikes.

Many thanks in advance if you can forward me the VTR fork dimensions, to compare with my measurements of my 95 VFR, if you do get the chance. I hope I can find out soon before the real nice "Coerce" brand VTR100 fork braces also dissapears from eBay for good (well there is still the VTR1000 Superbrace option, but I'm not as enthusiastic about getting their's after they just seem to ignore my request for information). There's a few guys here in the forum that are also interested in finding a fork brace for their 3rd and 4th gen VFRs.

I will need the center to center dimensions in millimeters between the VTR1000 fork caps and the diameter of the thickend part of the VTR1000 lower slider near the fork seal, minus the thickness of the fork protectors.

Beck

95 VFR

[FotoMoto]

Unless you are prepared to completely rebuild the VTR forks, I don't recommend this.

I've owned two superhawks and the stock forks are undersprung for that bike (the vtr is lighter than any VFR making matters even worse) and they are improperly valved causing hydraulic lock on hard bumps especially under braking. Plus they don't have compression damping either.

My advice: get a set of F4 or F4i forks, brakes, fender, triples, clipons and completely transform your front end. These are stronger 43mm diameter (thus you need the triples), have compression and rebound adjusters, stock springs are a closer match, and closer to the same length, plus you will have MUCH better brakes, can use the VFR front wheel, rotors, and, IIRC, the axle/spacers too.

Just my 2cents.

[SAFE-T]

I've owned two superhawks and the stock forks are undersprung for that bike (the vtr is lighter than any VFR making matters even worse) and they are improperly valved causing hydraulic lock on hard bumps especially under braking. Plus they don't have compression damping either.

:fing02: What he said. Why bother putting something crap on your bike when there is an obviously better alternative that is the same amount of effort ?

Should be able to find a decent set of F4/F4i forky boingers for around $200 plus postage. I bet there is at least one 4th gen VFR owner out there who pretzeled their front end and would be willing to give you $200 for your good VFR forks. Done.

[Guest]

Well thanks to all especially thx 1139, don't think I could have wished for a more concise answer. Bent forks arrived yesterday so I am going to go down the firestorm route, upgrading springs and cartridges when I get round to stripping them. I owned a firestorm back in 98 and never had an issue with the forks or brakes but take on board the issue of weight difference between the two models (I too have put on the pounds since firestorm ownership!). I'm going to take my time accruing the various bits and still am not decided on which master cylinder or clutch reservoir set up. May even change the clip ons - anybody know about compatibility of these and what the various options are?

[thx1139]

:fing02: What he said. Why bother putting something crap on your bike when there is an obviously better alternative that is the same amount of effort ?

43mm F4 forks are possible, and have adjustable compression; but certainly would require more effort.

43mm triples required, and CBR trips' offset would increase trail significantly. Blackbird triples are 43mm and have an offset closer to the 4thGenVFR (even closer than 6thGen). Ignition switch lock may, or may not work with Gen4 frame.

41mm VFR clip-ons no good anymore. F4 are much lower. Blackbird has similar height, but further forward. 6thGen clips much higher than 4thGen, fairing interference likely. Chopped/rewelded Helibars another option.

Different spacing on 43mm fork. 4th gen wheel/rotor combination won't work. 5th/6th gen might. Note that 5thGen are still 41mm, but also have a different spacing than 4thGen. Bolt pattern is different, so both wheel and rotors must be swapped out.

[FotoMoto]

Different spacing on 43mm fork. 4th gen wheel/rotor combination won't work. 5th/6th gen might. Note that 5thGen are still 41mm, but also have a different spacing than 4thGen. Bolt pattern is different, so both wheel and rotors must be swapped out.

I guess I better removed the stock 4gen VFR wheel and rotors I've been using with my F4i forks for the past year and a half since you say they won't work. :unsure: :unsure: As I said above, I'm not sure but I think I did have to get F4i wheel spacers ($6 or so) and maybe the axle. I don't recall for sure as I have too much stuff laying around in unlabeled boxes in the garage. :fing02:

[SAFE-T]

Good discussion.

Don't feel bad that we're dumping on your choice a bit. I got the same comments from Hispanic Slammer when I was looking at (older/non-radial caliper) YZF-R1 forks. I eventually went with RC51 forks, which are now dumped on by zRoYz in favor of, you guessed it, (newer/radial caliper) YZF-R1 forks.

[thx1139]

I guess I better removed the stock 4gen VFR wheel and rotors I've been using with my F4i forks for the past year and a half since you say they won't work.

Hey! not nice to scare the old people into thinking they're loosing their mind! (birthday yesterday) :goofy:

OK, just measured the offset of the rotors on my Gen4 and my buddy checked his 600F4. F4 spacing was wider. That would make them not interchangeable; -at least not without the extra effort of shimming the calipers to fit a narrower VFR rotor spacing.

[Beck]

Well thanks to all especially thx 1139, don't think I could have wished for a more concise answer. Bent forks arrived yesterday so I am going to go down the firestorm route, upgrading springs and cartridges when I get round to stripping them. I owned a firestorm back in 98 and never had an issue with the forks or brakes but take on board the issue of weight difference between the two models (I too have put on the pounds since firestorm ownership!). I'm going to take my time accruing the various bits and still am not decided on which master cylinder or clutch reservoir set up. May even change the clip ons - anybody know about compatibility of these and what the various options are?

I can't see why the Firestorm forks cannot be tuned to perform better anyway. firmer springs and maybe some re-valving plus some fork fluid height/viscosity changes might do wonders to get it to perform much better than OEM VTR and VFR forks. The bonus is, you will have 4 piston calipers instead of the 750's cheapy, wooden feeling sliding two pot units. Just tune those up too with SS brake lines stronger biting pads and maybe even fancy it up with petal discs and you will have a front end that tons better than the original setup for the 750. you can get very good performance for street riding with the tweaked Firestorm units without the complication and costs related to going with a USD/radial caliper front end from a R1CBRGSXRNINJAbike!

Beck

95 VFR

[thx1139]

I can't see why the Firestorm forks cannot be tuned to perform better anyway. firmer springs and maybe some re-valving plus some fork fluid height/viscosity changes might do wonders to get it to perform much better than OEM VTR and VFR forks. The bonus is, you will have 4 piston calipers instead of the 750's cheapy, wooden feeling sliding two pot units.

Actually the internals are all generally alike. Open up a 2008 CBR600RR 41mm USD fork and inside is basically the same 20mm cartridge design used for the last two decades. The valves will swap straight into an older fork; VTR/VFR/F4/whatever. No doubt though, adjusters for rebound and compression are nice to have when tuning.

Brakewise; I found my old 2 pot sliders give decent feel with some extra attention. Clean and lube the pins and bushings, polished pistons, clean o-rings, assembled with Sil-Glyde, blablabla.

It's easy to misplace blame on the old caliper design for trouble caused elsewhere in the system too. At one trackday my front brake feel was so grabby the lever seemed like a ratchet. Impossible to be smooth; they were either on or off. I cleaned & rebuilt the master cylinder, polished the pivots, re-assembled with the Sil-Glyde and back-bled with fresh Castrol LMA dot4.

The improvement was like day vs night!

[Beck]

I can't see why the Firestorm forks cannot be tuned to perform better anyway. firmer springs and maybe some re-valving plus some fork fluid height/viscosity changes might do wonders to get it to perform much better than OEM VTR and VFR forks. The bonus is, you will have 4 piston calipers instead of the 750's cheapy, wooden feeling sliding two pot units.

Actually the internals are all generally alike. Open up a 2008 CBR600RR 41mm USD fork and inside is basically the same 20mm cartridge design used for the last two decades. The valves will swap straight into an older fork; VTR/VFR/F4/whatever. No doubt though, adjusters for rebound and compression are nice to have when tuning.

Brakewise; I found my old 2 pot sliders give decent feel with some extra attention. Clean and lube the pins and bushings, polished pistons, clean o-rings, assembled with Sil-Glyde, blablabla.

It's easy to misplace blame on the old caliper design for trouble caused elsewhere in the system too. At one trackday my front brake feel was so grabby the lever seemed like a ratchet. Impossible to be smooth; they were either on or off. I cleaned & rebuilt the master cylinder, polished the pivots, re-assembled with the Sil-Glyde and back-bled with fresh Castrol LMA dot4.

The improvement was like day vs night!

I should do a brake caliper clean-up overhaul too very soon. I haven't really bothered with them too much except to clean them externally with doses of brake cleaner spray and pad inspections. I would appreciate a "day and night" improvements on my two pot brakes too anytime!

BTW, it looks like you also own an 88 Hawk GT. I had one too (a grey 1988) before I got my 95 VFR. I really miss that bike. I still think it out-handles my 95 VFR in a big way and I didn't have to mod it too much to improve it (just lower CBR1000 bars some OEM suspension tuning and a Telefix fork brace plus auxilliary driving lights for better visibilty in the twisty mountain forest roads. Some of the best/most exciting rides of my life was on that 88 Hawk. Hope you get to keep yours and enjoy it for a loooong time too! :squid:

Beck

95 VFR

[FotoMoto]

I can't see why the Firestorm forks cannot be tuned to perform better anyway. firmer springs and maybe some re-valving plus some fork fluid height/viscosity changes might do wonders to get it to perform much better than OEM VTR and VFR forks.

WOW, so buy a stock set of forks and then spend all that money, time, and effort to upgrade them yet still not have compression adjustment?

ALLLLLL righty then! :comp13: :biggrin:

[FotoMoto]

Brakewise; I found my old 2 pot sliders give decent feel with some extra attention. Clean and lube the pins and bushings, polished pistons, clean o-rings, assembled with Sil-Glyde, blablabla.

I'm looking at your "in the garage" stable and see nothing newer (streetbike wise) than 1996. Is that your newest reference to braking power?

[Beck]

I can't see why the Firestorm forks cannot be tuned to perform better anyway. firmer springs and maybe some re-valving plus some fork fluid height/viscosity changes might do wonders to get it to perform much better than OEM VTR and VFR forks.

WOW, so buy a stock set of forks and then spend all that money, time, and effort to upgrade them yet still not have compression adjustment?

ALLLLLL righty then! :comp13: :biggrin:

Wouldn't the right CBR600 fork internals and caps get you that??

Beck

95 VFR

[FotoMoto]

Wouldn't the right CBR600 fork internals and caps get you that??

Nope. Compression adjuster is on the external bottom of the fork leg casting.

[thx1139]

BTW, it looks like you also own an 88 Hawk GT. I had one too (a grey 1988) before I got my 95 VFR. I really miss that bike. I still think it out-handles my 95 VFR in a big way and I didn't have to mod it too much to improve it.

*Amen* Hawk Brotha!

Mine's also a gray '88. Comparing it to a VFR is comparing a tank to a 10speed. I'd literally ride it thru the doorway and up and down the narrow aisles of the warehouse where I worked. Mine forced me to develop corner technique because it was so damn gutless in a straight line. Whatever I do to my VFR is with the goal of making it handle more "Hawk-like".

The CB-1 is every bit as fun. Had bought it for a girlfriend. At 6' tall I look like a circus clown on the thing, but I'm laffin' out loud in my Arai. We rode it 2 up through 129/Deal's, and schooled a guy on a ZX-7!!!

As they say, more fun being fast on a slow bike, than being slow on a fast one.

[thx1139]

I'm looking at your "in the garage" stable and see nothing newer (streetbike wise) than 1996. Is that your newest reference to braking power?

Nahh, look at my avatar. That bike's not even two years old.

Personally, I don't have need or want for more braking power out of my 4thgen. I try to focus on smooth inputs to the controls, which generally limits aggressive brake use. Never found concern for exceeding the potential of the stockers. I even like factory Honda pads.

Since you're curious; that f4 of my buddy who helped confirm the different rotor spacing mentioned above, was previously titled to *me*. I am a little familiar with that fork.

Also had seat time on VFR800s, an R-1, 929, 954... Somewhere under a workbench I even have a pair of the exact same 6 piston Tokicos you grafted on.

Irony: after logging some hours on a Suzuki TL1000R, I noticed that while Tokico 6pots power was good the feel was nothing to write home about. F4 Nissins way better. I left the Tokicos in a box. Now I hear a popular upgrade for the Gix1k guys is replacing their "wooden" Tokicos with 954 parts.

Re-valving carts cost me a whole $20 pack of shims. Already had Eibach fork springs. Adjustable comp is nice, but to me not worth the price of juggling new bars/cable lengths/brake plumbing/ -and that butt ugly F4 fender. Once adjusters are dialed in I'll never touch 'em again anyway. And I'd staple my d!ck to a burning building before adding more trail to a VFR.

To each his own.

Wait, you are from Texas?

Isn't that the home of "11 turns in 318 miles"?

:biggrin: hehe Nevermind!

[Beck]

BTW, it looks like you also own an 88 Hawk GT. I had one too (a grey 1988) before I got my 95 VFR. I really miss that bike. I still think it out-handles my 95 VFR in a big way and I didn't have to mod it too much to improve it.

*Amen* Hawk Brotha!........

The CB-1 is every bit as fun......... We rode it 2 up through 129/Deal's, and schooled a guy on a ZX-7!!!

As they say, more fun being fast on a slow bike, than being slow on a fast one.

I also loved it when my Hawk and I left two squids on a 1K Gixxer and a CBR900 in the dust up in the mountian twisties and sweepers near Alice's. The joy from that ride lasted me weeks (and still makes me smile everytime I remember it) and really convinced me that Honda got it so right with the Hawk 647GT! :biggrin:

I do have to admit that I was thoroughly dissapointed when the VTR1000 came out. It seems to have just forgotten what they have learned on the fantastic Hawk. I think that's the point when Honda started losing their "vision" for their new bike designs.

Damn, I really miss my Hawk!!

Beck

95 VFR

[flyguyeddy]

heres what i did with my VFR and firestorm forks.

all i did was swap the lower part with my vfr stuff and the damping rod/fork cap/rebound valve assembly into my stock cartridge. check my build thread for more info.

[Guest]

heres what i did with my VFR and firestorm forks.

all i did was swap the lower part with my vfr stuff and the damping rod/fork cap/rebound valve assembly into my stock cartridge. check my build thread for more info.

That is an awesome write up flyguyeddy - is the bike finished yet? seems like youve done the bulk of the work already. What did you do or have done to get the alloy engine looking so clean?

So far I have sourced and stripped the vtr sliders ready for powdercoat, Got myself a pan european master cylinder, a vtr mudguard and a front axle should be on it's way from ebay as we speak and I'm just debating whether or not to get some early fireblade calipers (believe these will fit). I've also ordered ohlins uprated springs. I think I'll probably have to stick with my stock vfr dampers and forgoe the extra adjustability of the firestorm parts - the forks I salvaged the sliders from were quite badly bent and the damper rods were also bent. I have managed to bend these back to almost true and the area of bend is above the cartridge body and does not interfere with the action but I'm a bit reticent about using them. I also thought about stripping these and seeing if a local engineering place could replicate the rods as yet I am undecided... opinions please....

[flyguyeddy]

heres what i did with my VFR and firestorm forks.

all i did was swap the lower part with my vfr stuff and the damping rod/fork cap/rebound valve assembly into my stock cartridge. check my build thread for more info.

That is an awesome write up flyguyeddy - is the bike finished yet? seems like youve done the bulk of the work already. What did you do or have done to get the alloy engine looking so clean?

So far I have sourced and stripped the vtr sliders ready for powdercoat, Got myself a pan european master cylinder, a vtr mudguard and a front axle should be on it's way from ebay as we speak and I'm just debating whether or not to get some early fireblade calipers (believe these will fit). I've also ordered ohlins uprated springs. I think I'll probably have to stick with my stock vfr dampers and forgoe the extra adjustability of the firestorm parts - the forks I salvaged the sliders from were quite badly bent and the damper rods were also bent. I have managed to bend these back to almost true and the area of bend is above the cartridge body and does not interfere with the action but I'm a bit reticent about using them. I also thought about stripping these and seeing if a local engineering place could replicate the rods as yet I am undecided... opinions please....

i have not completed the bike yet, but really all i have to do to get it to a running state is install and modify the wire harness. i dont have the cash for the rest of the fairings so i have not really done anything with it.

i painted the engine with silver engine paint so thats why it looks so good. i pressure washed it first to get rid of all the nasty garbage that was stuck to it.

i would go with the the f4i/954/929/rc51 brakes myself but thats just because i went with them