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F3 fork cartridge swap for 98 vfr


HispanicSlammer

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I don't have either fork and probably never will but read the whole thing. A sign of an excellent write up! :goofy: Good job HS.

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Ok, I have one 5th gen fork leg apart and the F3 parts also and did compare them.

Here all on the floor, F3 on right, 5th on left side

post-880-126686364772_thumb.jpg

Then I started to compare the damper rod whit rebound valve,The F3 is shorter thanthe 5th gen by ~10mm

post-880-126686370205_thumb.jpg

Then the top caps, the F3 is ~20mm longer than the 5th gens preload adj. fully out.

post-880-126686368507_thumb.jpg

Then the damp rod bodys. As sade before the 5th gen has a additional spacer under this (~10mm spacing). The bodys are same lengt on both but the full out stop spring (rebound spring?, I call it that) is located different. If you put them side by side so botom is at same level and the 5th gens haveing the spacer on (like pic below ,F3 left 5th gen right), the return spring is at same height.

post-880-126686366705_thumb.jpg

That make me think I will leave the spacer out. by that I compensit the 10mm so whit the 10mm shorter damp rod and 20mm longer cap the leangth is the same as stock in teory. Also if I would add the spacer it would allow the fork leg to extend 10mm further. 10mm more travel?

On the other side, asemled the 5th gen interials are about 2,5cm longer (whit under spacer) than the F3 package fully out posisson. That meaning the interials (rebound valve) will stop the rebound movmet to full not the rebound spring (the F3 rebound valve is longer than the 5th Gens and not allow the F3 to extend as long as the 5th gen parts). That makes me think of trying to mix. The F3 rebound valve/damper rod whit the 5th gen outer tube ( I find non other differense than the reb spring posisson on them), to get the rebound spring closer. This will shorten the travel by ~10mm thro, but I have not had any problems whit fork botoming out, so maby the risk is worth to take? On the other hand no one clame they have problems as derect use, so why not do like other?

Edited by keny
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You will need that oil spacer since the vfr fork bottom bolt will not properly screw into the compression valve body without it. I have it in mine and I have the same setup.

Ok, thanks for that info.

I´m seriusly thinking of useing the 5th gen outer body (right one in pic below):

post-880-126686366705_thumb.jpg

As I then get some fork movement as stock, not 10mm extendede. Also I think of cutting the spring spacer (or made new ones) at onec as the spring feels OK for me (I´m not that heavy 73kg) and I had preload adjusted so nearly fully out on the stock fork and spring will be cramped ~20mm comperd to that whit the F3 preload adjuster fully out. Not using the bottom spacer would have helped that by 10mm, but if needed....

Edited by keny
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Ok, first I hope you dont mind I continue on your topic HispanicSlammer?

I now have first fork leg back together.

I started by putting in new slode bearings for the fork leg, and new seals. I usually une a small plastic bag on top of the leg to avoid the seal getting damaged, and put some light grees on the seal so its lubed for a long time.

post-880-126695671055_thumb.jpg

Then I again tock some mesurments.

First I compared the upper fri lengt of the 5th gen and F3 interials.

post-880-126695667913_thumb.jpg

post-880-126695666084_thumb.jpg

About ~11mm lenth difference as the as the outer tube bodys are at even height, 5th gen lower spacer not mounted.

Then the head cap difference from low point (where upper spring stopper come against.

post-880-126695669705_thumb.jpg

Some ~33mm differense. From that I asumed I need about that mutch shorter distanser for the spring. As I use the stock spring (and valves for that matter) the stock spacer is 50mm long, so I need a 20mm long spacer.

As I could not make a new one (have a frien that does that for me) and I didnt want to cut the stock one, I proceed to see how long the leg will be compared to the other (stock) one that I still hadnt open.

And by the way I did use the 5th gen outer valve tube so the rebound stop will be in stock place, not 10mm more upp, and ofcorse the stock spacer.

post-880-126695672505_thumb.jpg

As I had the spring in place I was supriced that if I had a 30mm shorter spacer, the spring would not be against the upper stopper!, a ~20mm shorter spacer would be more right. (sorry no pic of this) As I remeber you did cut the spacer ~10mm HispanicSlammer, my teory that using the F3 outer valve body will let the leg extend 10mm further compared to stock. As I had the cap scruvet to the fork tube, (after some words not sutable to print) as the spring was a pain to compress du to the to long spacer, I put the fork leg whit the F3 volve and head cap sid by side whit the one still haveing stock valve and head cap. And vola same length!

post-880-126695675151_thumb.jpg

post-880-12669567398_thumb.jpg

I would be intresting if I could get the mesurment how long a fork leg whit F3 oute valve body is. I would gess 10mm longer than the stock, but I hope someone that have done this mod can give me that (HispanicSlammer?), and I´m sorry I forgot to mesur how long the stock is. I have to check that and come back.

Alos one note. As fork leg fully extended the reb stop spring is stoping the movement not the valev rod even they are some shorter useing the F3 rod.

So now I just need to do the other leg and fet the proper spacer, maby I made my frien do diffren lenght ones so I can chose the best sutable onec, and not runnung to his shop many times :fing02:

Edited by keny
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  • 2 weeks later...

So I know from this thread that F3 guts drop into 5gen tubes, and F4 guts drop into 6gen tubes, but will F4i guts drop into a 5th gen? I have the opportunity to get a set of cartridges off a smashed up f4i at my local junker smile.gif

Also, would getting the lowers off the F4 do me any good, or just cause me to have to swap out the brakes? The forks themselves are toast, but the lowers seem ok...

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So I know from this thread that F3 guts drop into 5gen tubes, and F4 guts drop into 6gen tubes, but will F4i guts drop into a 5th gen? I have the opportunity to get a set of cartridges off a smashed up f4i at my local junker smile.gif

Also, would getting the lowers off the F4 do me any good, or just cause me to have to swap out the brakes? The forks themselves are toast, but the lowers seem ok...

F4/F4i are both 43mm tubes and the 5th gen uses 41mm tubes so no.

If your willing to De-Link the brakes then you can just slap a full set of F4/F4i forks on the bike and have fully adjustable forks. The F4/F4i fork lowers do nothing for you! :biggrin:

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F4/F4i are both 43mm tubes and the 5th gen uses 41mm tubes so no.

If your willing to De-Link the brakes then you can just slap a full set of F4/F4i forks on the bike and have fully adjustable forks. The F4/F4i fork lowers do nothing for you! :angry:

D*mn. I suspected as such. d*mn... :mellow:

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  • 1 year later...
  • 7 months later...

Sorry to bring this up again but I have just done this mod ... I used the F3 damper rods including rebound valves, and fork caps. I retained the VFR cartridge bodies, compression valves and lock pieces.I installed Racetech .95 springs. I figured by using the VFR cartridge bodies the rebound springs would be in the right position, and fork extension should be same as stock. I haven't had the chance to test it out yet, but would appreciate any thoughts, or experiences ..

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Ok ... 10wt oil, approx 20mm preload, 4 clicks back from max rebound, felt very firm and well damped. Felt a bit dead while just bouncing on them ... but felt nice and sure footed out on the road ... but then what would I know ? :tour:

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  • 1 year later...

I'm would like to change my brake disc, pads on my bike. It's fully original now.

Paralelly I just thought about whether swap the forks for CBR F3 or VTR, and the rear shock for CBR 929.

Am I see right that the front end "tuning" have this two ways?:

  • Swapping for a CBR F3 forks, with original brake and wheel.
  • Swapping for VTR forks with VTR/CBR brake that fits to this, so parallely I have to change the wheel too because of the diameter difference.

The rear end seems quite easier, with the 929 shock and some adaptation.

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