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naw, I pushed it as hard as I could on a frame I built. I've ridden bikes with unmodified stock frames and usd front ends and the stopping ability is markedly better than they were. hey, how come my post about swapping a gs650 crank into a gs550 bottom end didn't get any replies? guess this has become a haven for craggy old guys. ok ok I'll get off yer lawn
 

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how did this thread end up in the dumpster. The issue raised, though not very clearly, was that USD forks are usually shorter than stock old school forks and that fitting them to an old bike could very well cause handling, braking and safety to deteriorate.

Next point was that fitting modern forks with a modern 3.0" or 3.5" front 17" wheel would look a little odd on a bike with a 2.15" rear rim and on a shaft drive bike that isn't an easy problem to fix for most people.

Admittedly, some of the comments are framed in less than helpful terms, but this site tends to be a bit like that.

As for me, I have lowered, lengthened, shortened and raised bikes and in one case I have tried all the above on the same bike... I have fitted USD forks and monoshock rear ends to old bikes and braced the frames and although they will never beat a modern bike around a corner, they are better than stock IMHO. And I tend to reduce engine width if I lower the motor to avoid levering a wheel off the deck when cornering on the way to get coffee.

All that said, if I had a GS850, I would be wary of fitting modern suspension and wheels and would probably try a less radical approach to improving brakes and handling. Relatively modern calipers can be fitted and if it needed stiffer forks, a set of larger diameter GS1100 forks would probably drop straight it with little modification. There are ways to improve the looks and performance of that bike, but it's not the most suitable place to start to build a radical cafe racer.

If that's what you have, think in terms of suitable changes and forget what you see on pipeburn and other sites for art projects.
 

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Hi, I have a 1982 GS850gl. I'd like to upgrade my fork suspension to something more modern like the inverted ones. anyone know what would fit my GS?
I'm going to just answer his question....

First generation GSXR1100 USD forks are the longest you will find (91-94, I think). That's probably your biggest concern as in getting the longest ones to maintain your ground clearance. They also run the same steering head bearings so the swap is as easy as it will get if you get an entire front end.

The only problem will be they are over 25 years old and not that easy to find anymore.
 

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Shorter forks can occasionally be lengthened safely or paired with custom drop triples, stock rims can be spaced on the front axle with new bearings and spacers or a custom axle. Rear rims can be widened if you have $$$ burning a hole in your pocket.

But, I think the stiffer structure just is a poor match for the rest of a 70's and early 80's cradle frame unless it comes with additional modifications.

Nothing wrong with pointing that out to people.

- - - Updated - - -

IThey also run the same steering head bearings so the swap is as easy as it will get if you get an entire front end.

The only problem will be they are over 25 years old and not that easy to find anymore.
Don't forget the stem length...
 

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But, I think the stiffer structure just is a poor match for the rest of a 70's and early 80's cradle frame unless it comes with additional modifications.

Nothing wrong with pointing that out to people.
I kinda agree....and not.

I mean, how is using a stiffer fork a liability? If you put a fork brace on a conventional fork it's an "upgrade", right?.....replace the shitty sagged stock springs with new ones and that's an upgrade too....

I understand how the thought process is here with the stiffer forks highlighting the shortcomings of the chassis, but that's where you start frame bracing and modifying other components if you are serious about it.
 

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Why wouldn't you just use the whole rolling chassis and shoehorn the wrong motor into it
:I did that, when I was ~14 years old.
 

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I understand how the thought process is here with the stiffer forks highlighting the shortcomings of the chassis, but that's where you start frame bracing and modifying other components if you are serious about it.
If that is the plan then have at it! But I don't see most people asking about fork swaps having the knowledge or ability or even the desire to brace a frame to the extent of making a difference.

I see what you mean, but I'm thinking you are running into the area of rapidly diminishing returns, and the USD forks are at the far extreme given the price of some of these front end conversions.

They remind me of wings and spoilers and trash can sized exhausts on those japanese 4 bangers. All show...
 

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You missed the memo: Motivation for installing modern USD forks on a heavy old 4 cylinder bike has been fully explained, the USD fork upgrades are imperative so they can get the back wheel off the ground under braking without tucking under and eating shit.
 

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If that is the plan then have at it! But I don't see most people asking about fork swaps having the knowledge or ability or even the desire to brace a frame to the extent of making a difference.

I see what you mean, but I'm thinking you are running into the area of rapidly diminishing returns, and the USD forks are at the far extreme given the price of some of these front end conversions.

They remind me of wings and spoilers and trash can sized exhausts on those japanese 4 bangers. All show...
Can't argue with that.

Really, the question should be "What's a better front end to use on my GS850" rather than "Which modern USD front end should I use"?

To that end I would recommend a Bandit 1200 complete front end.
 

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naw, I pushed it as hard as I could on a frame I built. I've ridden bikes with unmodified stock frames and usd front ends and the stopping ability is markedly better than they were. hey, how come my post about swapping a gs650 crank into a gs550 bottom end didn't get any replies? guess this has become a haven for craggy old guys. ok ok I'll get off yer lawn
This craggy old guy would definitely be interested in hearing more about the frame you built. And I don't remember seeing anything about a crank swap but would like to hear more about that as well. This site has become too much about how you shouldn't do something instead of how I did something. And I may be part of the problem. I've spent a lot of time on my dyno this summer trying to get more power out of my Bridgestone and haven't posted a thing.

And by the way, stay the fuck off my lawn. I've spent too much time on making it look nice to have you damn kids mess it up.
 

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Can't argue with that.

Really, the question should be "What's a better front end to use on my GS850" rather than "Which modern USD front end should I use"?

To that end I would recommend a Bandit 1200 complete front end.
IMO that would even look better. And perform just as well on a stock frame.
 

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rather than make a shitty bike worse or hopefully better.....

why not go get the proper bike and ride it?

not everyone has to be a backyard engineer..... you could spend your summer riding.
 

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Its all good, the GS850 is a not a bad shaft drive tourer, its not an old sports tourer and to improve it a good service and refurb to bring it back to it's original spec, new bushes, oil, seals along with new (progressive) springs will be a good and easier route. Inverted forks where a fashion statement when first fitted to road bikes, heavier with poorer damping then the conventional forks they replaced. They are better now but without the high performance to go with them they are a waste of time and money, oh and yes they will be too short. If you really want later hardware look at maybe the 1200 bandit front end? But consider carefully, measure and then think again, and then check before laying out cash. Its the start of a process, with a new front end the front and rear wheels and worse the tyres will be mismatched so then you'll be faced with modifying the rear to fit the later wheel, then new rear suspension...By the time you've done all that you could have bought a later better faster bike! Good luck whatever you choose to do.
 

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fork guess

Hi, I have a 1982 GS850gl. I'd like to upgrade my fork suspension to something more modern like the inverted ones. anyone know what would fit my GS?
I kinda think I got on the wrong forum from XB3...s response. The longest quality sportbike forks I can find would probably be from a Ducati Multistrada or KTM ADV bike. Allballs sells a lot of conversion kits for races and bearings. Put as long a strut as your chain or shaft will take and see where the numbers fall. An angle finder, laser pointer and a plumb line will give you some numbers of rake and trail. Compare them to some bikes of similar length and weight that you would like your bike to handle like. Forget that crap of gotta be a single or twin of 60s 70s vintage, bent over, shaky stuff. Build what you like, ride like you want and have fun.
 

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... An angle finder, laser pointer and a plumb line will give you some numbers of rake and trail. Compare them to some bikes of similar length and weight that you would like your bike to handle like. ...
and then figure out how you are going to run the same tires and suspension as that Ducati.
 
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