CBR600F1 front end on GL1100

Hey guys - new to the forum and this is my first post...so go easy on me. ;D

Been looking for a project and decided that tearing down a comfy a Goldwing was the right choice for me. I picked up a 1980 GL1100 and have it mostly stripped down, just need to finish getting the motor out (...and cleanup and paint and..) and then it's time to start reassembly to build my café racer.

On to my question. I picked up a front end from a 1988 CBR600F1, complete with clip-ons, good forks, and calipers. I know it will bolt right up, but I'm having trouble coming up with options for a wheel and rotors... any help would be great.

are you trying to match the goldwing original wheel? obvious/easy wheel to bolt in is the hurricane wheel and rotors....but if you're trying to match the goldwing wheel I can help figure out what parts you need.....important info is axle diameter for both bikes, rotor diameter/bolt-pattern/offsett for the hurricane, and width of both wheels from rotor mounting face to rotor mounting face. after that it's not all that hard to search for stuff to fit.

And what new springs you want for those forks, as you will be putting forks from a 445lb bike on to a 600+lb bike.

The reason I went with the CBR600f1 was to have everything matched, forks/wheels/brakes. Too many variables to start mixing and matching rotors and calipers. Rotor size/offset is determined by caliper mount.

There were a number of reasons I went with the CBR front end, namely because the price was right, it would drop the front end a little, it bolts in nicely and other than the missing wheel/rotors, it was a complete front end. All that being said though, it looks like it may be a giant pain to match a front wheel.

I know the comstar wheels (like the ones on the Goldwing) came in various sizes and configurations and was hoping someone knew of one that might be an easy fit.

As far as the forks go I was planning on putting in new progressive spring (from Progressive Suspension).

It sounds like the on real option that isn't a huge amount of work is the CBR wheel. :'(

Marc - what did you use for a rear wheel?

FocusInProgress - here is some of the info you asked for. I'll get the rest in the next day or two.

Axle diameter:
GL: 15mm
CBR: 20mm

rotor diameter:
GL: 232mm
CBR: 276mm

bolt-pattern
GL: ??
CBR: ??

offset:
GL: ??
CBR: ??

I found some helpful info here: http://organ-donor.org/motorcycle-data/motorcycle-front-axle-diameter/

But still a ton of work to figure out what might work.

Cheers.

613Beast said:

Marc - what did you use for a rear wheel?

Click to expand...

My swap was on a CB400f. I utilized the CBR600f1 rear wheel there also. It required much machining to move the wheel left. Keep in mind the CBR wheels are 17"

I always use metalgear to find rotor specs....

http://metalgear.com.au/mgear-brake-disc-front-leftright-p-5355.html

looks like GL1100 is:

Outside Diameter 276
Inside Diameter 58
Bolt Hole Circumference 78
Bolt Hole Quantity 5
Bolt Hole Size 8.5
Thickness 5.0
Minimum Thickness 4.0
Offset 26.0

CBR600F:

Outside Diameter 276
Inside Diameter 144
Bolt Hole Circumference 166
Bolt Hole Quantity 6
Bolt Hole Size 10.5
Thickness 5.0
Minimum Thickness 4.0
Offset 0.0



so, you're in a bit of luck here....as the stock gl1100 rotors are the same thickness and outer diameter as the hurricane.

lets look at axle diameter....

http://www.dotheton.com/forum/index.php?topic=20952.0

according to that, gl1100 is a 15mm front axle....

hurricane is 20mm, so you'll have to source some wheel bearings if you wanted to run the GL1100 wheel in the hurricane forks.....I usually visit a local bearing shop and they can tell me in minutes what bearings I'd need to get the OD from the wheel to the OD of the axle and sell me some nice double sealed high-load-rated bearings....maybe you have a similar type of business to visit?

last thing to check is the distance from rotor to rotor on each wheel....if you're lucky, the 26mm offset of the GL1100 rotors on the stock wheel gets you within 1-2mm of the distance between the 0-offset rotors on the hurricane wheel (I'd put money the GL hub is narrower by far, and could work in your favor. basically, measure the center to center of the calipers of the hurricane forks mounted in the hurricane trees, then compare measuring the center to center of the gl1100 rotors while they're mounted on the gl1100 wheel....

All the hondas that have a 20mm front axle don't have a wheel that matches the goldwing. Actually, none of the wheels with a 20mm axle have a 276mm rotor.


so, easy would be find the matched hurricane wheel and rotors. What would be awesome/look factory would be convert gl1100 wheel to 20mm axle and make up some spacers to center the gl1100 wheel in the hurricane forks, and then see if you can get rotors to fit between the calipers....if 26mm offset doesn't do the trick, you can search metalgear by outside diameter and offset and bolt pattern to see if any other rotors will bolt up with an offset that works.


I hope this was helpful....

-Nick

Guys - thanks for all the help so far.

Nick - looks like metal gear was right and whatever info I found about the rotor size was wrong.

The GL1100 rotors are in fact 276mm

I measured the distance from inside rotor to inside rotor for the GL it's 122mm and for the cbr it's 108mm. Given that is a difference of 14mm, does that mean I'm essentially looking for rotors that have a 19mm offset? Assuming that's correct, I wasn't able to find anything. Is there options for two piece rotors with custom inner and outer rings?

For the wheels, it would be nice to keep the factory Goldwing ones so I assume I need wheel spacers and larger wheel bearings... if that's the case, I should be able to figure that out...

Thanks!

You got it...19mm offset does t really exist. I searched metal gear for 276mm and correct hub centerbore along with proper bolt pattern and this is the only one that might do the trick, at 14mm offset

http://metalgear.com.au/mgear-brake-disc-rear-p-6787.html

It is listed as a rear rotor, but doesn't say what bike for. Also says call for price. Maybe they'll be nice and tell you what it fits on the phone?

If it is a replacement for a factory rotor off something else, you could buy a pair cheap on eBay and just get 5mm washers and 5mm-longer mounting bolts for the calipers and be all set. Some larger bearings and new spacers and you'd be in business.

focusinprogress said:

I always use metalgear to find rotor specs....

http://metalgear.com.au/mgear-brake-disc-front-leftright-p-5355.html


I hope this was helpful....

-Nick

Click to expand...

I'm having a hard time figuring out that site. Where do I find the specs on certain rotors so I can find a replacement rotor. My wheel has the 6 bolt CB750 bolt pattern. I need a rear rotor and bracket that will work on that bolt pattern/offset/diameter.
When I search by bike it just brings up rotors for sale without giving the specs. Do they have reference chart for specs? When I use the search bar and search for a CB750 it brings up one rotor that is not close to being correct. Other than that one they show no rotors for a CB750. if they are out of stock on an item they show no specs or info for it.

o1marc said:

I'm having a hard time figuring out that site. Where do I find the specs on certain rotors so I can find a replacement rotor. My wheel has the 6 bolt CB750 bolt pattern. I need a rear rotor and bracket that will work on that bolt pattern/offset/diameter.
When I search by bike it just brings up rotors for sale without giving the specs. Do they have reference chart for specs? When I use the search bar and search for a CB750 it brings up one rotor that is not close to being correct. Other than that one they show no rotors for a CB750. if they are out of stock on an item they show no specs or info for it.

Click to expand...

I'm assuming since you mention rear rotor its for a cb750 super sport? What year?

focusinprogress said:

I'm assuming since you mention rear rotor its for a cb750 super sport? What year?

Click to expand...

None of the above. I have a set of Kimtabs that I am putting on a 1970 Triumph 650 Tiger with disc brakes. The bolt pattern on the Kimtabs is early CB750 74mm 6 bolt. I want about the smallest rotor I can run

This wheel:



Going on this bike:



I was hoping to be able to just collect the needed parts and bolt it up. Looks like my easiest option is going to be choosing the rotor/caliper/bracket and making a custom rotor carrier, axle and bearing carriers. Or at least using the axle for the specified rotor, caliper and bracket.

Shoot me a PM reminder Monday, I'll see what I can come up with

In the meantime, in the off-chance a rear has the same bolt pattern....90's Yamaha FZR rotors are the 6x74 bolt pattern up front as are many Ducati. Maybe something like an fzr400 or fzr600 rear rotor could potentially work. Or, scooters use small 3-bolt rotors, maybe a 3x74 would be the ticket. I actually have a set of scooter discs, I'll measure tomorrow.

focusinprogress said:

Shoot me a PM reminder Monday, I'll see what I can come up with

In the meantime, in the off-chance a rear has the same bolt pattern....90's Yamaha FZR rotors are the 6x74 bolt pattern up front as are many Ducati. Maybe something like an fzr400 or fzr600 rear rotor could potentially work. Or, scooters use small 3-bolt rotors, maybe a 3x74 would be the ticket. I actually have a set of scooter discs, I'll measure tomorrow.

Click to expand...

Focus, that has certainly given me some more options for front rotors that will bolt right up and be lighter than the CB 750 rotor on it now. Unfortunately the rear rotors have a much larger center hole, 115mm, so a carrier would still need to be made. Measure upside scooter rots and let me know what you come up with. I found an FZR rotor on eBay that the seller listed all the bikes it would fit on, lists around 24 different bikes to choose from for the front and 32 options for the front.

My apologies o1marc....


Finally remembered to look through my brake stuff, only found ONE scooter rotor, 3-bolt pattern is bigger than 74mm, more like 136-137mm. Snapped these pics for ya.

Thanks for the info Focus. The easiest way to accomplish what I want is to just weld a rectangular lug on the swing arm and mount up a SR650 caliper and bracket and matching rotor. Just need to fab a carrier for the rotor to wheel.