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Hyabusa Front End Conversion

gegg_247

Registered User
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Hello, Just thought I would share this....

I have a much loved 2002 Blackbird which after a small accident at Cadwell Park back in 2011 (not on the BB) had to have a flat bar conversion as my left wrist no longer supports the standard riding position!

We bought the flat bar conversion kit from jaws and after some buggering about got it fitted and have been using it ever since.

I have always wanted to fit some USD forks and have seen that some Hyabusa conversions have been done although I never really liked the fact that this meant machining bearings and a bit of bodged up ignition and steering lock.

After poking around on the web for what seemed an eternity I found a guy who made me some billet yokes to take a full busa conversion but retain all the orginal BB stuff.

On eBay I found a set of 2015 forks, wheel and mudguard and managed to get some original Brembo callipers form a breakers. There's a lot left to do yet but I dry fitted it all the other day and it looks great.

I think when the wheel (it's not an exact match but is three spoke) and the mudguard are painted and the new brake lines are in its gonna look the DB's.

I'll post some more pic's as I go along.

I can't speak highly enough of Roy from Billet Bike Bits http://www.ebay.co.uk/itm/Honda-Blackbird-Billet-Fork-Yoke-conversion-for-Hayabusa-TL1000-etc-forks-/331729784004
Whether you want a flat bar conversion or not I'm sure that he could sort something.

yokes.jpg

forks.jpg

BBFront.jpg

BBDash.jpg



Yes I know the bike is filthy, it gets ridden.

Hope this is helpful to someone out there.

Geoff
 
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noobie

Clueless in most things
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Good to know these conversions can be done. I think taffy has experience of busa and zx12r front end swaps and a few others have zx12r swaps.

Pictures are always great to see, I hope it goes well and look forward to the end result pics/impression.
 

ianrobbo1

good looking AND modest
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That looks spectacularly good, I take it the top mount is made to take and keep the HiSS for the injected bike,@tu*
 

stu56

Registered User
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Looks great but the only problem is the busa forks lower the front end by about 15mm. I got round this by having a top yoke made plus 75mm fork extenders to which fireblade clip-ons are mounted. Over the winter I will be replacing the springs with ohlins plus K-tech 20ssk fork valves.
 

gegg_247

Registered User
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Sorry for delay, I have mainly been drinking beer and laying about the place.

Yes the top yoke has been made to take all the original Honda stuff including the HISS.

As to the measurements, I measured the static sag on my bird before strip down and after install and I am not seeing a 15mm difference? I reckoned it was about 5mm. While I am sure that the BUSA forks are shorter I guess they are just that bit firmer which affects the sag.

I don't have to worry about clip on's so I have a bit more latitude to slide the fork if required and I currently have the rear shimmed up by 6mm (which I would like to remove) so I am hoping that this will work out about right.

I won't really know until I ride it but at least I have stuff I can adjust now.
 

ianrobbo1

good looking AND modest
Club Sponsor
As I said it looks spectacularly good,@tu* well beyond my abilities to do myself though, and would take some saving up to get all the parts needed, oh well if I come up on the Lotto!! :dunno: along with a supercharger!! :-0)
 

ianrobbo1

good looking AND modest
Club Sponsor
That looks well Stu,@tu* how does it handle compared to before the fork swap please??:dunno:
 

stu56

Registered User
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I would say it handles better but not by miles, fork springs are only slightly stiffer 0.93 The front seems to patter all the time and on less that smooth roads it's like riding a jack hammer , maybe not enough rebound damping but I am no expert. Over the winter I will be changing the springs for 1.00 Ohlins and changing the valves to either Ohlins 20mm fork piston kit or a K-tech 20ssk valve kit. I will let you know how it goes.
 

CBRDEAN0

Registered User
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As to the measurements, I measured the static sag on my bird before strip down and after install and I am not seeing a 15mm difference? I reckoned it was about 5mm. While I am sure that the BUSA forks are shorter I guess they are just that bit firmer which affects the sag.

That makes sense.

The BB the forks stick up through the top yoke around 40mm so you can attach the bars to the top part of them.
The Busa forks will sit level with your top yoke because you have a straight bar conversion - so they can be 40mm shorter than the BB forks and still allow almost the same ride height.
 

stu56

Registered User
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Looking back through my notes this is how I worked it out. Centre of spindle top of busa fork = 725mm Honda - centre of spindle to top of fork tube (where Haynes say you measure the 39mm to) is 728mm which is only 3mm short but what people do not take into account is where the top yoke sits in relation to the Honda yoke. If you use the busa yoke this sits 7mm higher so makes the busa forks 10mm short. If the yoke kit Gegg 247 had made sits the same then they are only 3mm short which is ok.
 

CBRDEAN0

Registered User
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Looking back through my notes this is how I worked it out. Centre of spindle top of busa fork = 725mm Honda - centre of spindle to top of fork tube (where Haynes say you measure the 39mm to) is 728mm which is only 3mm short but what people do not take into account is where the top yoke sits in relation to the Honda yoke. If you use the busa yoke this sits 7mm higher so makes the busa forks 10mm short. If the yoke kit Gegg 247 had made sits the same then they are only 3mm short which is ok.

From what I have seen - the std busa has the forks through the top yoke about 6mm.
You should be able to compensate for most of the 7mm based on your calcs.

PS - nice bike - who's top yoke did you use ?

Considering the USD route myself as a project to run alongside my current bike.
 

gegg_247

Registered User
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The top yoke has the same top as the original BB one so I think I'm good.
 

stu56

Registered User
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If you are using the original Honda parts you took off then yes.
 

stu56

Registered User
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The forks stick through the busa top yoke by about 12mm so when the top plate is on the yoke the preload adjusters are visible. If you raise the forks it will be hard to see how many lines are showing. Also if you use the busa top yoke you have to fanny about with the ignition mount. The top yoke was made by Topyokes.
 

stu56

Registered User
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Yes it is to fit the bird with the same ignition and steering lock but with the same rake as the busa lower yoke. The only problem with this is that the busa stem is thicker than the bird so you have to use a different top bearing and it is only available from china.
 

stu56

Registered User
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If you use the hayabusa yokes you need a 30 47 15 top race but you can only get a 30 48 15 so I had to use a 30 47 12 with a 30x47x 3mm thick spacer I had made up.
 
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