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Discussion Starter #1
I was wondering if any one could give me some advise, I have a 79 Yamaha xs750 project I want to start. I wanted to see if any one has done or herd of any one doing a swap of the forks? I would like to put inverted forks on it. I want to know if I can with little or no modification. Any advise would be great. Thank you.
 

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RSU to USD fork conversion is expensive.
USD are typically more difficult and expensive to facilitate routine service.
The triple trees & brake mounts are significantly different, with the forks set wider apart because they are so fat at the top, they have less turn clearance before colliding with the frame.
The USD replacements will likely be a fatter/stiffer forks in comparison to the the stock originals, largely because they will come off a more modern bike.

Curious, what features would make the USD fork a superior upgrade to an upgraded RSU fork, outside of visual appearance ?:I
 

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It's not easy to fit USD forks to an old bike and do it well.

If your bike is the soft chopper model the steering head rake angle is probably 30 degrees and the "normal" model would be closer to 28 degrees.

If you fit a smaller 17 inch wheel to go with the USD forks you will lose, say 1 1/2 to 2 inches in ride height. If you fit, say 1 inch longer rear shocks, it will effect the steering geometry by reducing rake and the trail of the front end. All these changes can add up to effect the stability and steering of the bike in a bad way.

You will get much more bang for your bucks if you just rebuilt the stock front end, get a real fork brace and some quality shocks like Hagons, (or about five other mid-price brands.) If you have the model with the leading axle forks, that really opens up a can of worms. The stock "boat anchor" wheels work O.K. and look very good painted.

Most guys on this site place function over fashion, so that's the kind of advice you'll get.

Putting a USD fork on is not as simple as finding out which ones will bolt on easily.

Danger, is my business.
 

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Bah humbug. Check over at Cognito moto for ideas. They sell hubs and triples to fit late model GSXR forks into Honda CB750s. Steering geometry is something you have to work through though. Most USD forks are shorter than our old RWU forks so it is critical to measure your forks and whatever you wwant to fit to avoid a front end that's too low because that creates all manner of issues. The other thing to think about is that with shaft drive you will not have a lot of choice of rear wheels and almost all USD fork wheels are wider than a stock XS wheel and that would look odd to say the least.

You might be better off looking at FZR400-600-750-1000 forks and brake calipers and make spacers to fit their disks on your stock skinny (and heavy) front wheel.

Theirs an XS triple forum somehere out there in internetland and I'm pretty sure that someone out there has already tried every combo under the sun and can tell you what works and what doesn't.
 

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Discussion Starter #5
Thank you every one is kinda figured that the swap would be difficult and maybe not worth it. You guy brought up good points so I just rebuild the stock forks.
 

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A real fork brace Like a Telefix/Weigl or a Superbrace will make the front end about 1/3 better and stiffer.

A quality brand of fork oil and a set of Progressive Suspension fork springs would make a big difference.

Good luck.

Danger, is my business.
 

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jus saying, companies like Paioli make some very nice modern suspension upgrade components that would nicely suit a classic motorcycle rebuild and update.:)
 
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