Jump to content
RossC

F4/F4i Forks - Apologies in advance

Recommended Posts

Hey all...I've searched a bit...but just haven't found a definitive answer. I'm sure this has been covered lots, so I apologize in advance. 

 

Got an 07 for use mostly as a commuter about a month ago.  I reached out to Jamie at DMR and will be getting his shock and will have him do the fork work.  

 

My question is regarding the F4/F4i forks.  Jamie recommends just using the lower fork legs with VFR uppers because of the length issue.  I didn't follow up with him to ask the next portion, but I will after some input from you guys. 

 

What is the length difference between the F4/F4i forks compared with the 6th gen vfr?  Aren't some of you running the complete f4 fork?  Are there clearance issues? I'm running stock forks raised 10mm currently and a little quicker turn in wouldn't hurt. 

 

I would imagine I'll wind up using the vfr uppers and f4 lowers.  But it would be nice to be able to sell off the complete vfr forks to recoup some of the costs.  I'm having a bit of a hard time justifying dropping $2k or so on a $3k craigslist special.  But then I think I'll have suspension and brakes I like...and a really good long term commuter. 

 

And a quick note, I appreciate that some of you like the linked brakes.  I'm sure I could learn to live with them, pretty sure Fast Freddy taught with them back in the day at his school.  But I don't want to. 

 

Thanks in advance for the help!

 

 

 

 

Share this post


Link to post
Share on other sites

F4 and F4i forks are not the same. F4i forks total length are shorter than VFR forks.  Also, the brakes from your VFR and fender wont work either.

 

The F4 ('99-'00) forks are indeed 795 mm in length to the VFR's 800 mm (funny that). The F4i forks are 785 mm. The end result is that the fork tubes sit about 10 mm below the handlebar top edge, but more than enough for the bolt to clamp, the handlebar-to-fork mount being 33 mm in height.

 

VFRworld threads are where I started my research: https://vfrworld.com/threads/vf4ir-the-project-begins.20085/

And

https://vfrworld.com/threads/vfr800-5th-generation-a-gearhead’s-delinking-brake-saga-and-the-interceptor-ss.3617/

 

Matt in Haymarket

 

 

Share this post


Link to post
Share on other sites
2 hours ago, zupatun said:

F4 and F4i forks are not the same. F4i forks total length are shorter than VFR forks.  Also, the brakes from your VFR and fender wont work either.

 

The F4 ('99-'00) forks are indeed 795 mm in length to the VFR's 800 mm (funny that). The F4i forks are 785 mm. The end result is that the fork tubes sit about 10 mm below the handlebar top edge, but more than enough for the bolt to clamp, the handlebar-to-fork mount being 33 mm in height.

 

VFRworld threads are where I started my research: https://vfrworld.com/threads/vf4ir-the-project-begins.20085/

And

https://vfrworld.com/threads/vfr800-5th-generation-a-gearhead’s-delinking-brake-saga-and-the-interceptor-ss.3617/

 

Matt in Haymarket

 

 

Wow, I didnt know my 13 year old delink post was still active. Not sure its all valid anymore either and its primarily for 5th gen...... 

I think the OP is talking about a 6th gen..... I'm sure guys have dropped in F4i forks on 6th gens, and probly have done the F4i fork lower with VFR uppers too. 

Dont forget to take care of the rear brakes too with a master cylinder change to 14mm. 

Share this post


Link to post
Share on other sites

Also, I believe the travel is different between VFR and F4i forks. From memory, the VFR is 109mm and the F4i forks are 120mm, so the VFR cartridge tubes must be used in the new frankenfork to prevent the front tire bottoming out on anything it shouldn't.

Share this post


Link to post
Share on other sites

No Frankenfork for me. I used 6th gen triples, F4i forks, fender and calipers with my 5th gen wheel.

 

Matt in Haymarket.

 

 

Share this post


Link to post
Share on other sites

I used F4i forks, 954 calipers, CBR600RR 03 master, 6th gen triples and bars, F4i fender and the 5G wheel/axle/spacers on my 5G, was a great combination that gave me no issues at all. The only bit that did not align perfectly was the steering lock, and I used a couple of washers to lower the mechanism down from the top triple which worked fine. 

 

IMG_0014.JPG

  • Thanks 1

Share this post


Link to post
Share on other sites

On my 5th gen I went with Jamie's recommendation and used 6th gen fork tubes with F4i lowers. I really like the setup. 

IMG_0616 (3).JPG

Share this post


Link to post
Share on other sites
On my 5th gen I went with Jamie's recommendation and used 6th gen fork tubes with F4i lowers. I really like the setup. 
332867140_IMG_0616(3).JPG.eabd03fd721104abf938189b9216d847.JPG
I'm considering using 6th Gen fork tubes and F4i lowers on my 6th Gen. Looking at part numbers (90126) it looks like the lower cartridge retaining bolts are different diameters and lengths ( 8x27mm vs 10x35mm.) How did you overcome this issue? Did you use the 6th cartridge or install a custom one?

Sent from my ONEPLUS A6003 using Tapatalk

Share this post


Link to post
Share on other sites

F4 cartridges in F4 lowers with the F4 bolt. No issues there. The cartridges are the same external diameter so no issue using the 6G fork tubes. You can take any fancy valve parts (e.g. Gold Valves or similar) from the 6G cartridge and use them in the F4.

Share this post


Link to post
Share on other sites

If you’d do a little research then you would know that F4/F4i have fully adjustable forks, 1.Preload, 2.Rebound,3.Compression.

The 6th gen only has Preload & Rebound adjustment, the reason for swapping to F4 lowers is to gain Compression damping & for Brake delinking with much better front brakes.

 

The only consideration here is the damper rod length at full extension, if with the forks fully extended you have the damper rod out of the fork top just high enough to attach to the preload adjuster then they are good to go. So swapping lowers with their associated cartridge means using the same bolt/washer designed for it.

 

The one thing that has always Pee’d me off about Japanese manufactured bikes is they keep changing parts like damper rod bolt for no apparent reason, it would be much cheaper for all concerned if they’d pick a standard & stick to it. And don’t get me started on part numbers 😞

 

 

 

Share this post


Link to post
Share on other sites

Thanks guys, however is it possible to use the VFR cartridge with F4i lower cases only? The part numbers for the cases are 51420-mbw and 51520-mbw. I've managed to find some lower cases for a good price but obviously they don't come with any cartridges...

My main objective is to replace the linked brakes with brakes from a F4i. I would like to use as much of the vfr fork internals as possible initially to keep costs down....

The ultimate goal is to upgrade to a DMr BD20 fork cartridge but in the short term was hoping to get up and running with brake upgrade only...

Sent from my ONEPLUS A6003 using Tapatalk

Share this post


Link to post
Share on other sites

The F4 has compression damper adjusters at the bottom on the sliders, so if you use the VFR cartridge you will need a means to seal that extra hole. 
 

I fitted Honda cartridges to a Kawasaki lower, that had a much large bottom bolt. I turned the Kawa bolt down & cut a new thread to suit the Honda cartridge. You might be able to do the same, or use a sleeve to centre the VFR bolt in the CBR hole ! 

  • Like 1

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy.