Upside Down forks for my ZR750C1

For all your handling questions
arejay
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Joined: 05 Sep 2017, 12:12
Location: west sussex, england

Re: Upside Down forks for my ZR750C1

Post by arejay »

when I had the parts I needed I took a week off work and changed them over- around march time and then rode it like this for the whole summer, I was initially worried that the bike would become twitchy as the back end was raised quite a bit but I found that it was much better than before with no adverse effects on the handling at all
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arejay
Posts: 36
Joined: 05 Sep 2017, 12:12
Location: west sussex, england

Re: Upside Down forks for my ZR750C1

Post by arejay »

it took me till the following year to collect the parts for the front end and over the xmas shutdown it all went together while it was apart I spent a couple of days in the paintshop and gave it a new coat of shiny paint, although the forks are a fair bit shorter than the standard ones it still had no adverse affects on the handling it turns much quicker than it did but it is not in the least bit twitchy and I regularly ride it hard, it has been like this for a few years now without giving me any reason to want to modify or change it in any way and having ridden the bike before and after I can honestly say that for me- the modifications have seriously improved the handling and in my opinion also the look of the bike
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Richard
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Joined: 24 Aug 2017, 14:35
Location: Zeewolde NL
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Re: Upside Down forks for my ZR750C1

Post by Richard »

I've seen the other topic Stu and I guess I was a bit short (too busy) in my reply above... ;)

So the reasons why are twofold, I do like the looks and my current setup has some flex, not much but too much for me to keep it that way. I know we can improve the current setup but since I also want the looks I decided to go for the UPSD's.

Obviously it will be a lot of extra work but hey that's part of the hobby anyway. Thus far I've been working on the bike more than riding it but I don't mind. I have a pretty busy job and relaxing for a few hours in the garage does wonders in clearing my head again.

I think I will have to take a complete front end but before I decide I want to measure the current setup so I know what to look for. The Yamaha forks look promising though...

And thanks Arejay for your feedback. Your bike looks great! Also your remarks about the handling afterwards with shorter legs is valuable as that's one of the issues I have because most ones are shorter then the OEM ones.
Freddy
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Joined: 06 Sep 2017, 11:06
Location: Sydney Australia

Re: Upside Down forks for my ZR750C1

Post by Freddy »

Rob@TZP wrote:I had a quick read of the thread - you'd wanna be keen for USDs to go to that much trouble? I might be an old stodge but from what I've seen USDs don't make much difference on the street - but are designed for that little 'extra' at the track? Am I wrong??
Given both UDF's and traditional orientation forks can have cartridge damping ..... the primary advantage of UDF's is greater rigidity. The larger diameter outer fork tube has less flex that the inner tube. So by turning them upside down and bolting this more rigid section to the frame via the fork yokes the overall front assembly has significantly less flex. This orientation also allows longer outer tubes which places the fork bushings further apart, which again results in less lateral movement.

Like everything there is a downside, which is generally an increase in un-sprung weight. Like so many things on the internet, contrary to popular internet 'wisdom' the inner steel fork tubes bolted to the front axle are actually heavier than the alloy outer tubes that would be in this position in a 'traditional' arrangement. However the advantages of less flex is considered to far outweigh any disadvantages of increased unsprung weight.

So to the key question are UDF's superior in performance to an optimized traditional damper rod set up ........ maybe, maybe not. An optimized set of high-end UDF forks will most certainly be, but a cheap set of UDF with incorrect weight springs, poorly set up damping and no external adjustability, probably not.
kinkyfreestyler
Posts: 32
Joined: 04 Sep 2017, 18:52

Re: Upside Down forks for my ZR750C1

Post by kinkyfreestyler »

HI i FITTED A SET OF ZXR400 H1 FORKS TO MY 550 AND THE DIFFERANCE WAS NIGHT AND DAY ,THE ZXR FORKS AND A BIT OF A LEGEND AND AFTER I FITTED SOME HYPER/PRO SPRINGS THEY ARE AMAZING

THE ZXR FORKS WERE ABOUT 25 MM SHORTER WHICH STEEPENED UP THE HEAD ANGLE AND MAKES THE BIKE TURN IN A LOT QUICKER BUT THANKS TO THE LENGTH OF THE SWINGARM THE BIKE STILL REMAINS STABLE .

AND ALSO THEY LOOK REALLY COOL :D TRY THE ZX7R FORKS BUT YOU'LL NEED TO GET A NEW STEERER TUBE FITTED FOR THE HEADSET BEARINGS BUT A SMALL ENGENEERING SHOP SHOULDN'T CHARGE TO MUCH FOR THAT JOB.

HOPE THIS HELPS
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Richard
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Re: Upside Down forks for my ZR750C1

Post by Richard »

Thanks for your kind feedback. The ZX7R is on my list but still looking around for a longer type. So haven't made up my mind yet but hey the winter is long in the Netherlands ;)
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Richard
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Joined: 24 Aug 2017, 14:35
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Re: Upside Down forks for my ZR750C1

Post by Richard »

Just FYI, these are the Aprilia ones I bought this week, will comment further within my restoration topic with some better pictures
Ohlins from Aprilia rsv tuono 1000.JPG
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