Front end swap, chicken and egg....
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Front end swap, chicken and egg....

This is a discussion on Front end swap, chicken and egg.... within the Technical forums, part of the Caferacer.net Forums category; Hi there, I am rebuilding a KZ1300 and have decided that Benelli Tre K USD front forks (made by Marzocchi) will look great as well ...

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Thread: Front end swap, chicken and egg....

  1. #1
    Junior Member McBoney's Avatar
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    Front end swap, chicken and egg....

    Hi there,

    I am rebuilding a KZ1300 and have decided that Benelli Tre K USD front forks (made by Marzocchi) will look great as well as preserve the ride height so crucial with six exhaust pipes on a heavy bike. So I finally found a pair and bought them.

    Luckily the bottom of the steering pin where it goes into the bottom yoke is the same diameter as the KZ1300 so I can swap that out easily and keep that work standard (and thus simple). And a top yoke is easily made.

    However, I want to have a 17'' front wheel to match the rear for that cafe racer look, but that means finding another wheel with a similar spoke pattern, which will have another dia spindle and length, and also different brake discs and callipers etc etc. The Benelli had Brembo's, but unsure what kind and I have no idea how to start matching discs with wheels and callipers and make those all fit onto the forks I have.

    Where should I start? Suggestions greatly received.

    Paul
    1982 KZ1000P brat
    1979 KZ1300 six pot cafe project

  2. #2
    Junior Member Federicoca's Avatar
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    Quote Originally Posted by McBoney View Post
    Hi there,

    I am rebuilding a KZ1300 and have decided that Benelli Tre K USD front forks (made by Marzocchi) will look great as well as preserve the ride height so crucial with six exhaust pipes on a heavy bike. So I finally found a pair and bought them.

    Luckily the bottom of the steering pin where it goes into the bottom yoke is the same diameter as the KZ1300 so I can swap that out easily and keep that work standard (and thus simple). And a top yoke is easily made.

    However, I want to have a 17'' front wheel to match the rear for that cafe racer look, but that means finding another wheel with a similar spoke pattern, which will have another dia spindle and length, and also different brake discs and callipers etc etc. The Benelli had Brembo's, but unsure what kind and I have no idea how to start matching discs with wheels and callipers and make those all fit onto the forks I have.

    Where should I start? Suggestions greatly received.

    Paul
    I have the front wheel, "Brembo serie oro" Calipers, and Brembo serie Oro radial pumps.

    Inviato dal mio G8141 utilizzando Tapatalk

  3. #3
    Junior Member McBoney's Avatar
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    That would solve a heap of issues in one go and give me a much better front end than standard.

    Just need some measurements from you to calculate and make sure it will all fit, and that the ride height, trail and offset are not compromised.

    I will send you a pm

    Cheers
    Paul
    1982 KZ1000P brat
    1979 KZ1300 six pot cafe project

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  5. #4
    Senior Member TrialsRider's Avatar
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    Quote Originally Posted by McBoney View Post
    That would solve a heap of issues in one go and give me a much better front end than standard.

    Just need some measurements from you to calculate and make sure it will all fit, and that the ride height, trail and offset are not compromised.

    I will send you a pm

    Cheers
    Paul
    The wheel and brake shouldn't really be all that difficult, lots of Italian bikes used those same forks,
    you just need a donor bike that has been rear ended. ...which probably doesn't happen very much because they are all very fast bikes :|


    You do realize however, putting a nice Marzocchi front end on that lump of a motor and frame is going to leave you wishing the rest of your bike was built in Italy
    Last edited by TrialsRider; 11-09-2019 at 08:11 AM.

  6. #5
    Junior Member McBoney's Avatar
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    Thanks, the issue is size of spindle and distance from calliper to disc etc... but I'll get there.

    Yes, the 1300 was always a big lump and the frame was heavy to suit the engine and BHP. I did ride one however and quite liked the feel of it. Certainly my KZ1000P is no lightweight - although I stripped off more than 80Kg of Police accessories, which made a huge difference.

    I did lighten the frame wherever I could and I will not have many of the standard stuff on it and whatever I can upgrade to lighter and/or modern materials I will, so I reckon in the end I will have lightened the bike by at least 50KG. I also upgraded the rear suspension to Hagon Gas calibrated to my weight, and I will have proper tyres, so hopefully I'll be OK.

    But I am not a road racer so won't push it all the way very often.

    Paul
    1982 KZ1000P brat
    1979 KZ1300 six pot cafe project

  7. #6
    Senior Member TrialsRider's Avatar
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    The bike is a freight train.


    Doesn't matter how much weight you take off, what matters is what's left,
    everything behind the fork yokes except possibly the nice but massive motor is going to be the weak link.

    ... apparently they are perfect for some parts of Australia.

    You do realize those forks are designed to work with that big beefy axle, you can Not put some skinny ass old bolt through there like they use on an old bike, there might even be only one spring in those forks.
    Last edited by TrialsRider; 11-09-2019 at 09:24 AM.

  8. #7
    jcw
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    Senior Member jcw's Avatar
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    ive done a couple wheel swaps now.
    basically you need to machine new spacers to center the wheel in the forks. the Center spacer will need to be replaced as well unless the old wheel uses the same diameter axle.
    once you've got the wheel centered, you measure the distance from the hub where the disc mounts to the midline of the caliper.
    ISR in sweden used to cut custom stainless brake discs and aluminum rotor hats for your offset. im sure others do it.

  9. #8
    Junior Member Federicoca's Avatar
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    Hi Paul,

    I've sent you a PM. Let me know if the message has arrived, because sometime I have some issue with PM. Otherwise you can contact me directly on whatsapp +393393885220.

    Cheers,
    Federico

    Inviato dal mio G8141 utilizzando Tapatalk

  10. #9
    Senior Member TrialsRider's Avatar
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    This right here is not Just the axle, it's a fork brace.
    Don't mess around with Anything other then the correct axle for those forks.
    Is like comparing carriage bolts to helicopter shafts.

  11. #10
    Junior Member McBoney's Avatar
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    Quote Originally Posted by TrialsRider View Post

    You do realize those forks are designed to work with that big beefy axle, you can Not put some skinny ass old bolt through there like they use on an old bike, there might even be only one spring in those forks.
    There are definitely two springs, one in both forks, and new seals and oil that I have put in.

    The original Benelli axle is an aluminium hollow tube with a diameter much larger than the original KZ1300 axle, which is (only) a solid metal bar, but obviously up to the task of dealing with the KZ's power and weight.

    I am not an engineer but can understand that an axle also operates as a fork brace, but I am unsure how they would be much better than an original axle, with a properly centred and installed wheel...

    Thanks for the tip on ISR in Sweden. I can easily manufacture spacers, even an axle to suit the new wheel hub and fork spindle holes (subject to being educated on the merits of sticking to the original axle). The main concern I had was getting the discs running into the callipers correctly.
    1982 KZ1000P brat
    1979 KZ1300 six pot cafe project

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