Topic: 2003 Yamaha R6 fork on CB550

[pangloss]

I have done this conversion.. I deliberately offset the hub to the right (left hand disc only) so I didn't have to machine the caliper. The rim is centred by an offset laceup. Got a pro wheel builder to do that.



..

[Tews19]

Looks good and great attention to detail!

[RAFster122s]

That's right RAFster - he has the nice alloy ones... However, it's not the rim that need the extra clearance, but the spokes. If our hubs are the same, the needed clearance would also be the same I take it?

Maybe the dimensions (width) of the R6 forks are a little different. Mine is a slightly newer than his.

The WM3 rim is wider and he went with an 18" rim causing the angle to be a little sharper since it was closer to the hub and thereby interfers with caliper clearance a little more. Not a huge difference since we are talking 1/2" less radius and about 1/3 of an inch wider...
It all adds up.

Glad you were able to do it with very little machining on the caliper.

[Franky]

aaah! Yes, the 18" would make a noticeable difference. It's been a while since I read the FunJimmy thread - forgot about that.

[Franky]

Took the camera along for a ride the other day. Here are a few pics of the 'pretty much' finished bike...


Superbike handlebars are super comfy.


Got a parts-bike with a battered tank. Goes well with the rest of the bike though!


Lotsa stopping power!


The machined hub rules out a classic speedo. Here's the new minimalist set-up


Clean lines


Classic looks, dispite of the modern fork.


Love the old Honda badge. Found it in a small thrift-like shop in Asia.


All electronics under the seat, battery at the rear swingarm. Need to upgrade the pods... it runs fine, but I know it could run better...

[70CB750]

Very nice!

[Bankerdanny]

Really really nice. I would be proud to say I built that!

[FunJimmy]

Franky,

Nice job documenting (in detail) and providing drawings for this modification.
It's a great resource for everyone interested in updating their forks.

When I built mine, it was all done on a cocktail napkin and measured with vernier calipers and an ice cold beer.   

[SOHC4 Cafe Racer Fan]

The right-side-up fork conversation looks good -- a great stealth modern upgrade.  I like the seat quilting, too.  I'm on the fence with the dented tank.  I like the look of bare metal tanks, but my I would prefer a non-dented tank.  Just my $0.02!  Looks fun.

[jackseattle]

Really nice work and a great looking end product. 

[Franky]

Hi guys!

Thanks for all the kind words  - greatly appreaciated on a board like this, that has so many great builds and talented people!

A special thanks to you, FunJimmy,  for your inspirational build.  I'm usually also a napkin-planning-kinda guy, but the whole point of this thread was to make a how-to guide.

[Mike547]

If you guys are interested Congnito moto makes a hub for the GXSR front end swap.

http://cognitomoto.com/collections/frontpage/products/gsx-r-hub-bolt-on-conversion-laced-wheel-1

[FunJimmy]

If you guys are interested Congnito moto makes a hub for the GXSR front end swap.

http://cognitomoto.com/collections/frontpage/products/gsx-r-hub-bolt-on-conversion-laced-wheel-1

The GSXR front end conversion is a popular upgrade too, but a vastly different look and results than using conventional forks with classic laced wheels. This is subtle and elegantly executed, but I'm biased.

[saltcitycafe]

I am just finishing up my funjimmy r6 front end conversion.  Funjimmy and franky made it super easy and it works perfectly.  You guys deserve a medal

[Scott S]

Finding those long bolts was somewhat of a hassle.

 What size and length are the bolts? Are you using a nut on the other side to secure the rotors?

[nvr2old]

I'm curious as to how well the bicycle speedo works.  I fitted one to my 550F and it seemed to work well up to about 70mph where it's little brain then became overwhelmed.  It was a nice experiment, but in the long run, failed.  This was 7-8 years ago so maybe a more modern unit has worked for your application.

[FunJimmy]

What size and length are the bolts? Are you using a nut on the other side to secure the rotors?

Those are M8 socket cap bolts. They need to be long enough to extent through the hub and into the spacer on the opposite side. You may need to measure to order the required length. They do not secure the rotors! Rotors are fastened with M6 bolts.

[Scott S]

 So, let me get this straight: One side of the spacers is just an open hole, the spacer for the other side of the hub is threaded, and you use the long bolts to hold it all together?

[FunJimmy]

So, let me get this straight: One side of the spacers is just an open hole, the spacer for the other side of the hub is threaded, and you use the long bolts to hold it all together?

Correct! The spacers sandwich the hub.
One spacer has the socket caps recessed while the other is threaded.
Rotors are mounted consealing the spacer bolts.

[slikwilli420]

Try Allensfasteners.com. They have 5/16" bolts up to 6". The nominal difference between 5/16 and M8 is negligible and should work just fine.

[FunJimmy]

Try Allensfasteners.com. They have 5/16" bolts up to 6". The nominal difference between 5/16 and M8 is negligible and should work just fine.

Sacrilege! Imperial fasteners on a metric machine is intolerable. 

[Scott S]

The drawings are pretty much complete! And even better: On monday I'm going to meet a friend of a friend who works at a topnotch machine shop. Hopefully he'll have time to help out soon :-)

Below are some jpeg images of the drawings and here's a link to a scaleable PDF file  http://www.franky.dk/Honda/franky_fork-spacer-drawings.pdf . (Once I actually get the spacers and all done, I'll update both with whatever may change).


Overall drawing


Left Spacer


Right spacer


Hub

 On the drawing of the left spacer, what do you mean by "outer rest area" and "inner rest area"?
 I was writing down the bearing dimensions so I could look them up on the All Balls site and I'm not 100% clear on those two terms.

[754]

I think he means the fit into hub and rotor part...ie hub projection has to be within a few thou of hub id.
Discs to spacer projection can be a tad looser..

[Scott S]

 The more I look at it, the more I think he's referring to the lip that the bearing seats on. The pic shows a 40mm I.D., but I think maybe it's just mislabeled.
 I'd still like some clarification.

[RAFster122s]

The Center hole through the spacer is 40MM and the 44MM is the outer diameter of the bearing opening. Depth for bearing depends on what you need for the bearings you source. I don't see that depth identified. 
The bearing diameter would need to be 43mm in OD and axle diameter fitment in ID if 1/2mm per side is sufficient clearance for the bearing fitment.

FOR THE RIGHT & LEFT Bearing Carrier & Spacer
The space for the width of overall for the spacer and the thickness for each step in the thickness is identified (26mm)  the bearing side has a 59mm diameter that is 7mm before it goes to the 98mm overall OD for 14mm and then transitions back to 60mm diameter/OD for another 5mm.
I BELIEVE he has a error in the dimensions, backwards on the diameters on the bearing side and the hub side... They hub side that faces inward and goes inside the Hub should be 59mm and the Bearing size is 60mm, otherwise your bearings are going to be deep inside the hub and not have any pressure on the race other than an interior spacer (if made) to keep the bearings from working their way out of the spacers. You need that 1/2 mm clearance to fit inside the 60mm hole in the front hub.

The dimensions are for the CBR600 F3 brake rotor.  If you use a different rotor, then you have different dimensions.



The hub depth is 78mm with a center hole of 60mm
The amount you trim to get to 78mm will be different from side to side as the hub is not symmetrical, it will depend upon if you center it in the space between forks as to how much to trim off/face each side.