750 fork options

I have a '96 VFR750 and I'm intending to upgrade the forks, mainly so I can fit 4 piston brake calipers. �

I have a pair of low mileage VTR1000 Firestorm (Superhawk) front forks which I picked up cheaply because the fork tubes are bent. �I know I can fit my VFR fork tubes and internals to the VTR sliders, it's just a straight parts swap. �Can I fit the VTR internals instead? �I know the VTR springs are a bit soft, so could I use the VFR springs? �How much oil, and what weight do I need to use?

Lots of questions here I know, I'm hoping that someone will have done the modifications and I can learn from their experience. �Thanks in advance.

You would be MUCH better served by bolting up a set of CBR600F4/F4i forks. 43mm, 4 piston calipers, and along with a set of VTEC triples and handlebars you can retain (most of) the handling and comfort characteristics.

Oh, and they're fully adjustable too. :biggrin:

Edit: since you're in the UK, that would be the 99-2006 CBR600F Sport.

[image: View Post]SEBSPEED, on 17 November 2010 - 03:24 PM, said:

You would be MUCH better served by bolting up a set of CBR600F4/F4i forks. 43mm, 4 piston calipers, and along with a set of VTEC triples and handlebars you can retain (most of) the handling and comfort characteristics.

Oh, and they're fully adjustable too. :biggrin:

Edit: since you're in the UK, that would be the 99-2006 CBR600F Sport.

Thanks, but I already have the VTR forks and brakes. �I have a small budget and I just want the best outcome using the parts that I have


:)

[image: View Post]Druid, on 17 November 2010 - 05:37 PM, said:

Thanks, but I already have the VTR forks and brakes. I have a small budget and I just want the best outcome using the parts that I have

See, if Seb thought like that he'd have one or two rideable bikes and no projects, instead he is slowly buying up every spare bike part that hits the market, and wondering what to do with them :laughing6-hehe:

Try a PM to VFRD member JZH, who fitted VTR1000F forks to a 3rd Gen 10 years ago, he's in your neck of the woods too.

If you already the the parts... just give it a go.

[image: View Post]The Phantom, on 18 November 2010 - 02:09 AM, said:

[image: View Post]Druid, on 17 November 2010 - 05:37 PM, said:

Thanks, but I already have the VTR forks and brakes. I have a small budget and I just want the best outcome using the parts that I have

See, if Seb thought like that he'd have one or two rideable bikes and no projects, instead he is slowly buying up every spare bike part that hits the market, and wondering what to do with them :laughing6-hehe:


C'mon now mate, where's the fun in that?? :goofy:

Yes, you can use the VTR internals but the VFR ones might be better (I'll have to check my notes on that one). The VFR springs should work just fine. Run Honda Pro Oils 5w with an air gap of 120mm and you should be all set.

[image: View Post]JamieDaugherty, on 18 November 2010 - 09:00 AM, said:

Yes, you can use the VTR internals but the VFR ones might be better (I'll have to check my notes on that one). The VFR springs should work just fine. Run Honda Pro Oils 5w with an air gap of 120mm and you should be all set.



Just about to do this myself, I too have bought a set of firestorm forks (bent) and plan to fit the vfr750fv compression valve, transplant the firestorm rebound valve and use 7.5wt oil, (the uprated springs i bought suggest an air gap of 170mm and 10wt oil) but i find this a little harsh on high speed compression.
I thougt i would have to fit the cartridge from the vfr, to retain full fork travel as i understand the firestorm has a little less travel.
I would welcome comments as to my options, i don.tneed to uprate the brakes as i find them effective enough.

I'm running VTR internals with upgraded Traxxion valves and stiffer springs. With the VTR you get rebound adjustment. I used the stock VFR800 uppers and VTR lowers to get a brake upgrade. It works pretty well for a street setup.

[image: View Post]kblackburn, on 18 November 2010 - 04:21 PM, said:

[image: View Post]JamieDaugherty, on 18 November 2010 - 09:00 AM, said:

Yes, you can use the VTR internals but the VFR ones might be better (I'll have to check my notes on that one). The VFR springs should work just fine. Run Honda Pro Oils 5w with an air gap of 120mm and you should be all set.



Just about to do this myself, I too have bought a set of firestorm forks (bent) and plan to fit the vfr750fv compression valve, transplant the firestorm rebound valve and use 7.5wt oil, (the uprated springs i bought suggest an air gap of 170mm and 10wt oil) but i find this a little harsh on high speed compression.
I thougt i would have to fit the cartridge from the vfr, to retain full fork travel as i understand the firestorm has a little less travel.
I would welcome comments as to my options, i don.tneed to uprate the brakes as i find them effective enough.



A couple of thoughts:

• Use the VFR750's rebound valves on the VTR damping rods
  
• Use Honda Pro Oils 5w - nothing heavier
  
• Run an air gap of 120mm
  
• You should use the VFR's cartridge tube

Let me know if you need anything else!

[image: View Post]JamieDaugherty, on 19 November 2010 - 07:32 AM, said:

[image: View Post]kblackburn, on 18 November 2010 - 04:21 PM, said:

[image: View Post]JamieDaugherty, on 18 November 2010 - 09:00 AM, said:

Yes, you can use the VTR internals but the VFR ones might be better (I'll have to check my notes on that one). The VFR springs should work just fine. Run Honda Pro Oils 5w with an air gap of 120mm and you should be all set.



Just about to do this myself, I too have bought a set of firestorm forks (bent) and plan to fit the vfr750fv compression valve, transplant the firestorm rebound valve and use 7.5wt oil, (the uprated springs i bought suggest an air gap of 170mm and 10wt oil) but i find this a little harsh on high speed compression.
I thougt i would have to fit the cartridge from the vfr, to retain full fork travel as i understand the firestorm has a little less travel.
I would welcome comments as to my options, i don.tneed to uprate the brakes as i find them effective enough.



A couple of thoughts:

• Use the VFR750's rebound valves on the VTR damping rods
  
• Use Honda Pro Oils 5w - nothing heavier
  
• Run an air gap of 120mm
  
• You should use the VFR's cartridge tube

Let me know if you need anything else!

Jamie,
should i reface the valves before i refit into the cartrdges, with maybe some 2000 grit paper, to aid sealing, what do you think.

kevin

[image: View Post]kblackburn, on 19 November 2010 - 12:22 PM, said:

Jamie,
should i reface the valves before i refit into the cartrdges, with maybe some 2000 grit paper, to aid sealing, what do you think.

kevin


That's what I do. It's good practice to face stock valves. I haven't always done that and I can't really say that I could tell a difference. If it doesn't seal perfectly it would be just like the low speed needle was turned out a bit more.

[image: View Post]JamieDaugherty, on 19 November 2010 - 01:03 PM, said:

[image: View Post]kblackburn, on 19 November 2010 - 12:22 PM, said:

Jamie,
should i reface the valves before i refit into the cartrdges, with maybe some 2000 grit paper, to aid sealing, what do you think.

kevin


That's what I do. It's good practice to face stock valves. I haven't always done that and I can't really say that I could tell a difference. If it doesn't seal perfectly it would be just like the low speed needle was turned out a bit more.



Jamie,

any other recommendations whilst i have them in bits.

kevin

[image: View Post]kblackburn, on 19 November 2010 - 01:30 PM, said:

Jamie,

any other recommendations whilst i have them in bits.

kevin


New shim stacks for sure.

Jamie,

can't afford one at the momment, but i will have plenty of shims, vfr forks and vtr forks, any suggestions for stacks using what shims i will have available, some thing to smooth out the harshness of high speed compression, and should i rework the ports in the valves, i'm sure i've seen some reworked valves, don't know wether it was here or on another site.

kevin

[image: View Post]kblackburn, on 19 November 2010 - 02:19 PM, said:

Jamie,

can't afford one at the momment, but i will have plenty of shims, vfr forks and vtr forks, any suggestions for stacks using what shims i will have available, some thing to smooth out the harshness of high speed compression, and should i rework the ports in the valves, i'm sure i've seen some reworked valves, don't know wether it was here or on another site.

kevin



Unfortunately you won't get there with the shims available in those two sets of forks, not even combined. There just isn't the right parts you would need to make good stacks. Throw out the HMAS valves in the VTR forks. Don't mess with the ports on the VFR valves, they are fine just like the are now.

Thanks to everyone for their replies, esp Jamie who seems to be something of an expert on this. �

VFR internals it is then. �Do I measure the oil gap with the spings in or out?

[image: View Post]Druid, on 20 November 2010 - 06:22 AM, said:

�Do I measure the oil gap with the spings in or out?

Springs out.

[image: View Post]V4 Rosso, on 20 November 2010 - 06:56 AM, said:

[image: View Post]Druid, on 20 November 2010 - 06:22 AM, said:

�Do I measure the oil gap with the spings in or out?

Springs out.



More specifically, with the springs out and the forks completely compressed.

[image: View Post]JamieDaugherty, on 20 November 2010 - 09:36 AM, said:

[image: View Post]V4 Rosso, on 20 November 2010 - 06:56 AM, said:

[image: View Post]Druid, on 20 November 2010 - 06:22 AM, said:

�Do I measure the oil gap with the spings in or out?

Springs out.



More specifically, with the springs out and the forks completely compressed.


Thanks

Well guy's,

I've done the fork damper rod change, using vtr top caps damper rod and vfr750fv compression and rebound valves as suggested, I've put 5wt oil in also as suggested.

I have static sag of 12mm and combined with rider sag of 30mm, this is using the same spacers that i had in the vfr originally, it does, however, seem very soft when you bounce on the front forks, as though the oil is too light, there is only a marginal difference when the rebound is wound fully in, I must say I have not ridden the bike yet, so can not comment on performance on the road,so I will test ride tomorrow, weather permiting, and report back.
Druid, how are you getting on with your fork rebuild ?


kevin

The rebound adjustment only affects the speed of the decompression stroke - is that the "softness" you're talking about?

It sounds to me like you're saying that you want more compression damping, and/or a stiffer spring.

Seb,

the spring was fine in the old setup, although it's progressive, Hagon recommended 10wt oil with the spring kit, I have taken Jamie's advise and used 5wt and an air gap of 120mm. the compression with 10wt felt harsh on high speed hits.
I have just backed off the preload adjusters fully out and can still only get rider sag of 30mm, I installed the vtr top caps with my vfr shortened spacers, now the vtr damper rod was shorter than the vfr rod by approx 18mm, so I am now thinking I need to remove the spacer to get some decent sag figures and after riding tomorrow will evaluate wether I need to change to 7.5wt oil.

kevin

Try bumping the oil height up to 110mm before you change the weight. Don't do that until after you get your sag where you want it though.

Ok Guy's

before test ride this morning, i have removed the spacers (25mm),because the new hagon progessive springs( start at 6.5kg/ raising to 10.5kg according to hagon tech dept) are longer than the standard honda items,and the damper rods(vtr) are shorter than( the vfr), oil height set at 130mm (5wt), free sag now 20mm and with rider 35mm, rebound set in the middle of the 3 turns, from full on to full off.

Been out 50 mile ride, twisties around the lake district, it felt s*** to begin with, but I think that was me( convinced myself 5wt was too light), however, it does seem to handle the smaller undulations with ease, I think it needs some more rebound dialing in, should have taken some tools with me to make adjustments, but that I will do another day.I have measured total travel on the forks, 95mm, so there is some travel in reserve, so I could wind another 1/2 turn of preload off, or reduce the oil height slightly, I'll see how the rebound feels at 1/2 turn out from full in and then make a decision regarding the 7.5wt oil, What does every one think about grinding the step away on the rebound rod ? does it give more adjustment or is it just finner.

kevin

[image: View Post]kblackburn, on 21 November 2010 - 07:38 AM, said:

Ok Guy's

before test ride this morning, i have removed the spacers (25mm),because the new hagon progessive springs( start at 6.5kg/ raising to 10.5kg according to hagon tech dept) are longer than the standard honda items,and the damper rods(vtr) are shorter than( the vfr), oil height set at 130mm (5wt), free sag now 20mm and with rider 35mm, rebound set in the middle of the 3 turns, from full on to full off.

Been out 50 mile ride, twisties around the lake district, it felt s*** to begin with, but I think that was me( convinced myself 5wt was too light), however, it does seem to handle the smaller undulations with ease, I think it needs some more rebound dialing in, should have taken some tools with me to make adjustments, but that I will do another day.I have measured total travel on the forks, 95mm, so there is some travel in reserve, so I could wind another 1/2 turn of preload off, or reduce the oil height slightly, I'll see how the rebound feels at 1/2 turn out from full in and then make a decision regarding the 7.5wt oil, What does every one think about grinding the step away on the rebound rod ? does it give more adjustment or is it just finner.

kevin


Please describe why you feel it needs more rebound. What is the bike doing over bumps?

Seb,

It feels to rebound too fast, if I bounce on the front I get the return followed by a second return, instead of 1 and a half bounces. I like my bikes to rebound slower ( done lots of cross country mtb racing). my son had a vtr we had rebound dialed on the slow side and that felt really strong at the front and i could push it into corners,so I am trying t get a similar feel, I would like to do the odd track day next year, but doubt I would be able to push hard, we have a track bike for my son, steel framed cbr600, again with slower rebound. He also has a zxr6r road bike, again with rebound set on te slower side, that feels good aswell, I know these are not the same, but there is no reason that a vfr can't be dialed in similar.

kev

Almost always when you "feel" that the problem is with the rebound it's actually compression. If you are running stock shim stacks then I'm not at all surprised that you are feeling that. It's probably a little fast on the rebound but I wouldn't think it's too bad. Your problem is compounded by the progressive nature of the springs. Straight rate springs are a must-have to get you started in the right direction. A different shim stack setup would really get you planted.

[image: View Post]JamieDaugherty, on 21 November 2010 - 09:42 PM, said:

Almost always when you "feel" that the problem is with the rebound it's actually compression. If you are running stock shim stacks then I'm not at all surprised that you are feeling that. It's probably a little fast on the rebound but I wouldn't think it's too bad. Your problem is compounded by the progressive nature of the springs. Straight rate springs are a must-have to get you started in the right direction. A different shim stack setup would really get you planted.


And if the budget is tight, a switch to 7.5 or 10w would serve as a band aid.

[image: View Post]SEBSPEED, on 22 November 2010 - 06:46 AM, said:

And if the budget is tight, a switch to 7.5 or 10w would serve as a band aid.


Going to a heavier weight fluid to correct for improper valving is certainly not advised. In fact, this would have some il-effects that negate any potential improvements, making it a step in the wrong direction.

[image: View Post]JamieDaugherty, on 22 November 2010 - 08:24 AM, said:

[image: View Post]SEBSPEED, on 22 November 2010 - 06:46 AM, said:

And if the budget is tight, a switch to 7.5 or 10w would serve as a band aid.


Going to a heavier weight fluid to correct for improper valving is certainly not advised. In fact, this would have some il-effects that negate any potential improvements, making it a step in the wrong direction.



Such as?

In this case he would just be reverting to the weight that was in his forks before.

Isn't a second for rebound where you should want it?

[image: View Post]SEBSPEED, on 22 November 2010 - 11:04 AM, said:

Such as?

In this case he would just be reverting to the weight that was in his forks before.



The obvious one is the dramatic increase in low speed damping because you are trying to push that heavy fluid through the same orifice. The low speed effects all over in fact, so this could cause issues all over. I don't know anyone who has been successful by upping the fluid weight.

[image: View Post]JamieDaugherty, on 22 November 2010 - 11:30 AM, said:

[image: View Post]SEBSPEED, on 22 November 2010 - 11:04 AM, said:

Such as?

In this case he would just be reverting to the weight that was in his forks before.



The obvious one is the dramatic increase in low speed damping because you are trying to push that heavy fluid through the same orifice. The low speed effects all over in fact, so this could cause issues all over. I don't know anyone who has been successful by upping the fluid weight.


My point is that the valving he's using right now was meant to be used in conjunction with Honda's SS-8 which is "10w". You know I use that term loosely because of differences in actual weight across brands. He has switched to 5w and is having issues with fast rebound and I could be wrong, but I feel lead to believe that he's on a budget - putting new springs and better valve setup out of the equation for now.

So, 2 interim solutions given budget... buy shim washers and toy with the stacks, or change the oil back to SS-8.

Agree?

Are you sure stock isn't SS-7 (5w)?

[image: View Post]JamieDaugherty, on 22 November 2010 - 12:51 PM, said:

Are you sure stock isn't SS-7 (5w)?


1992-2009 uses SS-8. Not sure on the VTR - going to Google now...

Hi Guy's

vtr uses 10wt as standard, as my son ran one up to very recently when he changed to the zxr6r,
You are correct in that I am on a tight budget and would love to play with the shim stacks, but don't understand, which shims effect what, part of the compression and rebound
.I did note that after my ride yesterday the tyres were still cold and struggled to get any heat into them, yes is it was damp and cold, but even so they usually warm up.

kev

Another reason the stock suspension has issues! That also supports what I've found - just a change to Honda Pro Oils 5w by itself is an improvement. Back to my original comment, going to a higher weight of oil is the wrong thing to do.

The SS's are not nearly as good as the Pro Oils, by the way. The SS versions are original equipment but the Pro Oils is the high performing fluid. Pro Oils 5w is what I use for all fork applications I setup.

Well, I did my fork swap over the weekend

[image: Posted Image]

I picked up this pair of Firestorm forks quite cheaply, because the tubes are bent. I intend to fit the VFR tubes and internals into the Firestorm sliders, which will allow me to fit the uprated brakes. First, loosen the fork top. It's much easier to do this when the forks are still held in the yokes.

[image: Posted Image]

Remove the brake calipers, wheel and front mudguard, I had to use an axle stand under the engine to support bike. Then loosen the bolts in the yokes and slide the fork out, I did one at a time - it's easier to keep track of things that way. There's a drain screw in the bottom of the VFR forks, remove it and pump the fork to drain the oil then undo the bolt in the bottom of the fork leg

[image: Posted Image]

then undo the fork top and withdraw the cartridge

[image: Posted Image]

Prize off the dust cover to access the fork oil seal, or the bit of rag that has been carefully inserted by previous owner to soak up the oil that leaks past the seal ::)

[image: Posted Image]

The oil seal is retained by a circlip, once this is removed the forks can be disassembled. This is the VFR fork parts and the Firestorm slider

[image: Posted Image]

Reassemble the forks using new oil seals and refit in the yokes. You need to use the Firestorm wheel spindle, but the VFR front wheel fits like it was made to be there

[image: Posted Image]

I need to get a Firestorm front mudguard, the VFR one has different mounting points.

�25 for the Firestorm forks, �6 for the front wheel spindle and �8.95 for the oil seals. �A pair of Firestorm calipers cost �30, and they bolt straight on as you would expect. The calipers are not quite central on the disc but a couple of washers sorts that out.

[image: Posted Image]

The standard VFR master cylinder is too small at 12mm, it works but there is far too much lever travel. Fortunately I had a 14mm Nissin master cylinder which is what is needed. I had to make a bracket for the reservoir from a bit of aluminium, it bolts into the mirror mounting hole in the handlebar clamp (from a Suzuki Bandit iirc)

[image: Posted Image]

Two braided steel brake hoses connect the master cylinder to the calipers, they took a while to bleed but I now have a nice firm lever, and much better brakes than previously.

Nicely done!

Well done. Can you tell us why the valves/cams/covers look gold? I do not remember my 3rd gens looking that way, is it just build up of some kind?

Thanks for sharing.

[image: View Post]VIFFER93, on 23 November 2010 - 11:48 AM, said:

Well done.��Can you tell us why the valves/cams/covers look gold?��I do not remember my 3rd gens looking that way, is it just build up of some kind?

Thanks for sharing.

Yes, it's some kind of build up - oil burning on to hot surfaces perhaps? �It does come off, but it's quite hard work to remove it. �

istr that vegetable oil can cause deposits on engine components, perhaps somebody used Castrol R in it at some stage?

Anybody know if the vtec fork springs will fit my 750fv, just might be able to get some linear springs .9, which should be fine for my weight.

kev

[image: View Post]kblackburn, on 23 November 2010 - 02:16 PM, said:

Anybody know if the vtec fork springs will fit my 750fv, just might be able to get some linear springs .9, which should be fine for my weight.

kev


The 02+ VFR springs are larger in diameter and won't work - sorry.

[image: View Post]kblackburn, on 23 November 2010 - 02:16 PM, said:

Anybody know if the vtec fork springs will fit my 750fv, just might be able to get some linear springs .9, which should be fine for my weight.

kev


No, but 98-01 VFR and CBR600F2 & F3 will.

[image: View Post]kblackburn, on 22 November 2010 - 01:19 PM, said:

vtr uses 10wt as standard, as my son ran one up to very recently when he changed to the zxr6r,

Yes, but the RC36 VFR750s all used 5wt, and that's what the valving is from. The VTR forks have HMAS valves in them, which have been ditched, no?

(I used Race-Tech Gold Valves in my VTR forks, which is a whole different ball game...)

Ciao,

JZH

thanks for your input, I had been using 10wt oil in the vfr, recommended by the local honda dealer, just found a copy of the workshop manual online, it say ss7 which i understand is 5wt, no wonder my forks felt hash, so it's a whole new feeling to get used to.So all I need now is some advise on rebound valving to give me the feeling I want, how many shims to add, what size and where ?

kevin