This is a discussion on Fork upgrade within the Parts For Sale forums, part of the Classifieds category; 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 ...
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
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.
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.
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.
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kijiji has a listing for a 1988 gsxr1100 complete rolling chassis minus the motor, even has ownership papers, 1000$ Canadian, located in Toronto.
front end certainly looks massive enough, should only add a few pounds
Last edited by TrialsRider; 07-24-2018 at 06:38 PM.
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.
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.
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...