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Discussion Starter #1
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
 

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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
 

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Discussion Starter #3
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
 

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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
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
 

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Discussion Starter #5
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
 

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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.
 

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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.
 

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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

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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.
 

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Discussion Starter #10
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.
 

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...
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. ....
Sorry but No it's not!
Those forks require the rigidity of that large diameter axle to keep the fork legs from going ups and down independently, but you will find out.
carriage bolts connected to helicopter shafts

 

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Discussion Starter #12
Ok, thank you for the advice.

I had already decided not to put the original wheel back in and have now found two options. One a wheel off a BWM 1100gs and another off a Kawasaki GS 1000 and both have significantly thicker spindles.

I shall investigate what size these are and pick the most suitable.
 

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... One a wheel off a BWM 1100gs and another off a Kawasaki GS 1000 and both have significantly thicker spindles. ....
The front axle off the modern BMW is likely about a 200$ one inch diameter, precisely machined length of titanium,
while that is off a mono-shock front end bike and not one fitted with USD forks it's still definitely a major upgrade from the cheesy half inch steel carriage bolt and spacers concept :cool:
 

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Discussion Starter #14
I prefer the BMW wheel, but the original axle is only 20mm thick. The Benelli spindle holes are 25mm (screw end) and 30mm (clamp end).

But it is the axles are the same length (so I can also use the Benelli lower yoke).

Is the BMW 20mm original axle enough? If I use the original axle, I need to somehow do something at the fork spindle ends to make those fit a small dia axle... which is of course possible, but I won't bother if a 20mm dia axle is not deemed strong enough...
 

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I prefer the BMW wheel, but the original axle is only 20mm thick. The Benelli spindle holes are 25mm (screw end) and 30mm (clamp end).

But it is the axles are the same length (so I can also use the Benelli lower yoke).

Is the BMW 20mm original axle enough? If I use the original axle, I need to somehow do something at the fork spindle ends to make those fit a small dia axle... which is of course possible, but I won't bother if a 20mm dia axle is not deemed strong enough...

Your front forks are Not something you want to ever have fail catastrophically. I don't want to see you hurt, so I'm going with the safe answer which is; you should not mix and match front suspension components that were never designed to operate together like that or catastrophic failure is on you and not the manufacturer.
 

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Discussion Starter #16
You will all be glad to know I have managed to secure an original wheel and spindle to the forks, as well as brembo brake callipers, all from the Benelli Tre K Amazonas. It is a nice enough wheel, the right size, and the fact that the spindle and brakes etc. simply bolt on means so much less work, and as mentioned here, probably the safest.

Now the entire front end comes from one bike... lets see if the back end can keep up! ;-)

Paul
 

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Discussion Starter #17
Setback: the wheel appeared to have a small dent in it and when I took the tyre off for a specialist to look at maybe repairing that (some small dents can be repaired by specialists), he immediately noticed a crack as well. I hadn't seen the crack as it was so small, but after rubbing some yellow crayon on the area, it was clearly visible

So lesson learnt: Check second hand items VERY carefully and preferably get a specialist to look at them.

Wheel is scrap...

IMG_9148.JPG
 

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Not surprised, seen lots of rims like that & way too many people will sell absolutely anything just to make a few bucks.
 
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