Front fork: rebuild / swap to upside down with weight reduction?

Discussion in '5th Generation 1998-2001' started by fury, May 12, 2019.

?

Rebuild or swap to U/D?

  1. Rebuild the OEM forks

    1 vote(s)
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  2. Go for U/D.

    0 vote(s)
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  1. fury

    fury New Member

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    Hello.

    So I have a situation where any advice would be extremely helpful.

    The problem is the clunking noise when compressed and overall, soft front fork. Springs are progressive, a little bit out of range (too long, in fact) than stated in manual. Stanchions are worn out (less thick than stated in manual). I replaced the bushes in February, that didn't helped. The front lower fork legs (most likely) are done. I didn't had any tools to measure the inner diameter of them, when I rebuilded forks in February.

    Possible solutions:
    1) To get a new / used, but good lower stock fork legs, then new stanchions, linear, matched my weight springs, bushes, seals and oil, rebuild everything. The costs ... around 400 Eur without the fork legs. The legs itself would set me back for 100 EUR or more, I guess?

    or

    2) Go for upside down front forks with brake separation and weight reduction. RC51 front forks would be kind of difficult to get (I am located in North Europe, you do not see them on every corner). R1 forks would a solution. The costs at the moment are difficult to understand, as I would need (correct me, if I am wrong) the triple trees, forks, brake calipers, wheel itself, spacers (?), brake lines, cables, front wheel cover fairing / wing + linear springs, fork rebuild etc.

    From my point of view, weight reduction would be helpful in the future, as I am competing with bikes much lighter than my VFR. On the other hand, combined brakes are helpful in Moto gymkhana, as the bike is more effective in braking (you just need to go much faster to use this as an advantage). Also CBS helps to reduce the 360 turn radius.
    I am doing everything myself, so I am not paying anyone else for the work on my bike.

    This is the video showing the way how I ride, just for you to understand, what the question is all about.


    Any input or opinion, or advice whatsoever will be highly appreciated.


    Thank you.
     
  2. mello dude

    mello dude Member

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    I guess it depends on what you are after and how much you want to spend. I went with VTR lowers on VFR upper tubes.
    That allowed mounting up with RC51 calipers as a bolt on. Other people have used 954RR/F4i calipers. Then of course you have to change the master cylinder.
    With this configuration, you keep the wheel and rotors, and you keep the triples/bars.
    The rear, you need to bridge the caliper pistons together and go to a 14mm master.
    Just stripping out the linked system is a 6.5 pounds weight savings. The big part of it is dropping most of the weight off the forks, especially the boat anchor secondary master cylinder on the left fork.
    Also, for the forks internally, I went with 1.0kg springs and Traxxion Dynamic valving.
    (I'm sure in Europe there should be a popular fork upgrade builder.) The rear shock I have is a Penske.
    For me, there has been no downside on this, the bike was transformed.


    If you go to a USD, that is much more involved parts list and much more money....

    Cheers
     
    Last edited: May 13, 2019
  3. fury

    fury New Member

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    I was waiting for more replies, but anyway. Mello Dude, thank you indeed for the information.
    As the season is open, my guess is that as a temporary solution I will get another front fork off a 5th gen, give it a light refurbish (bushes, oil, seals, measure everything), after that will try to ride it till the end of the season. After that will see.
    What interests me is the necessary changes if the USD route is chosen, more specifically, if the CBR1000RR forks are being used, should I use the front wheel too with brake disks off the same bike?
    The same question goes to R1 forks - the front wheel off the R1 should be used, correct?
     
  4. NorcalBoy

    NorcalBoy Member

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    You can make just about any set of forks work on any bike, you can also fit just about any cartridge to any fork. Wheels too. All you need is a good machinist.
     

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