750 fork options

[Druid]

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.

[SEBSPEED]

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.

[Druid]

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

:)

[The Phantom]

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.

[Guest]

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

[SEBSPEED]

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:

[JamieDaugherty]

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.

[kblackburn]

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.

[mello dude]

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.

[JamieDaugherty]

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!

[kblackburn]

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

[JamieDaugherty]

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.

[kblackburn]

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

[JamieDaugherty]

Jamie,

any other recommendations whilst i have them in bits.

kevin

New shim stacks for sure.

[kblackburn]

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

[JamieDaugherty]

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.

[Druid]

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?

[V4 Rosso]

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

Springs out.

[JamieDaugherty]

 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.

[Druid]

 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

[kblackburn]

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

[SEBSPEED]

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.

[kblackburn]

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

[SEBSPEED]

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.

[kblackburn]

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

[SEBSPEED]

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?