Topic: a thinner,lighter repro front brake rotor work on a CB350/400F front wheel ?

[grcamna2]

I have a CB400F front wheel w/ stock 4 bolt mount front rotor and wondered if anyone makes a repro that mounts with the same dimensions/size,etc. but is thinner/lighter ? The stock disc is heavy stainless and i think an improvement(lightened cast iron?) would help.

[flybox1]

Yeah...gotcha right here!
Jeff does great work.  I have two of his rotors on my 750.
http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Parts+and+service/Brake+Rotors+_+Thinned+and+Drilled/HONDA+Front+brake+rotors+CB+350K-350F-360-400F/

[grcamna2]

Yeah...gotcha right here!
Jeff does great work.  I have two of his rotors on my 750.
http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Parts+and+service/Brake+Rotors+_+Thinned+and+Drilled/HONDA+Front+brake+rotors+CB+350K-350F-360-400F/

Those look very cool   

[Godffery]

Yeah...gotcha right here!
Jeff does great work.  I have two of his rotors on my 750.
http://www.vinmoto.org/gallery/v/VinMoto-Garage/album03/Godfferys-Garage-123/Parts+and+service/Brake+Rotors+_+Thinned+and+Drilled/HONDA+Front+brake+rotors+CB+350K-350F-360-400F/

 Thanks for the good word Man !

[754]

Cast iron and stainless pretty close to same weight.. I think I would run a much thinner Stainless , than a really  thin cast iron..

[Bodi]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

[grcamna2]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

I wouldn't even mind if it was just drilled w/o being thinned,I guess it would still be lighter.

[robvangulik]

Just drilling  made 1 disc 750 grams lighter, so both discs together made a difference of 1,5 kilogram.

[slikwilli420]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

Using two of them.

[MoMo]

Bill, I have a pattern to drill a 400f rotor.  I've done a couple, doesn't take all that long and eats up one cobalt bit.   If you like I'd drill yours gratis...Larry

[754]

Honda over engineers everything, partly due to liability.
Pretty sure they like the piston to not go out further than need be...
Honda does not recommend it, but as with most racing stuff , there is always some sacrifice...so probably shorter component life. Hi performance modded stuff should be inspected more frequently than stock.

Note how thin most rotor are now, and many are floaters to avoid warping..? Stock Honda discs from the seventies are Stone Age...

[grcamna2]

Honda over engineers everything, partly due to liability.
Pretty sure they like the piston to not go out further than need be...
Honda does not recommend it, but as with most racing stuff , there is always some sacrifice...so probably shorter component life. Hi performance modded stuff should be inspected more frequently than stock.

Note how thin most rotor are now, and many are floaters to avoid warping..? Stock Honda discs from the seventies are Stone Age...

The stock are heavy but they sure have lot's of extra life built into them 

[Godffery]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

Brake Rotors were relatively new technology in the 1970's so they erred on the side of caution, by the late 70's early 80's they already started getting thinner and drilled.  I have done allot of these and found that 4.3mm is the "Sweet spot" and now I do all my drilled & thinned rotors to that thickness. Also; the number, size & location of holes is critical as well.

[grcamna2]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

Brake Rotors were relatively new technology in the 1970's so they erred on the side of caution, by the late 70's early 80's they already started getting thinner and drilled.  I have done allot of these and found that 4.3mm is the "Sweet spot" and now I do all my drilled & thinned rotors to that thickness. Also; the number, size & location of holes is critical as well.

Thanks Jeff,PM sent.

[Godffery]

Why does Honda specify minimum thickness 6mm - if this is a stock disk thinned to 4mm, what makes it immune to that specification?

Brake Rotors were relatively new technology in the 1970's so they erred on the side of caution, by the late 70's early 80's they already started getting thinner and drilled.  I have done allot of these and found that 4.3mm is the "Sweet spot" and now I do all my drilled & thinned rotors to that thickness. Also; the number, size & location of holes is critical as well.

Thanks Jeff,PM sent.

If you sent a PM to me, I don't think I got it...?  If you'd like, you can contact me directly at jstephens7@wi.rr.com 

[grcamna2]

I'm still waiting for a reply to my last email Jeff,thanks.

[Godffery]

I'm still waiting for a reply to my last email Jeff,thanks.

Oh, ok. Got that and just replied.

[grcamna2]

I'm still waiting for a reply to my last email Jeff,thanks.

Oh, ok. Got that and just replied.

thanks

[RAFster122s]

Slotted will help with water evacuation for wet braking improvement while brake performance can be improved with proper application of holes for gas and material evacuation.

[sixthwisconsin]

I have Jeffs rotors on both my 550 & 750f.
Highly recommended.

[grcamna2]

Those look good sixthW  I'm purchasing from Godfferry also.
These oem machined rotors are looking like a much better choice than some chinese repro.

[Godffery]

 Thanks for posting Pix, I always love to see these on the bikes!
I hope to be starting an album of Customer builds on my web site soon, I trust you won't mind me using these Photos...? 

[sixthwisconsin]

Let me get you a couple of beauty shots of the whole bikes complete. If the OP doesn't mind, I'll just post them here for you to grab.

[grcamna2]

Let me get you a couple of beauty shots of the whole bikes complete. If the OP doesn't mind, I'll just post them here for you to grab.

Sure,love to see them myself.

[flybox1]

.

[Godffery]

Let me get you a couple of beauty shots of the whole bikes complete. If the OP doesn't mind, I'll just post them here for you to grab.

Sure,love to see them myself.

GROOVY !

[sixthwisconsin]

Here is the cb550k0
The 750 I'm shooting tomorrow morning. I realized I never shot finished pictures of it!
The 550 is going through V3 over the winter. Nothing major, paint, bars, tail light.



Adding the 1975 cb750f

[grcamna2]

Here is the cb550k0
Photobucket is broken right now so attached.
The 750 I'm shooting tomorrow morning. I realized I never shot finished pictures of it!
The 550 is going through V3 over the winter. Nothing major, paint, bars, tail light.

You've got dual CB750 brakes and rotors on it? it must stop w/ one-finger at speed 

[sixthwisconsin]

The 550 & 750 have the same rotors & calipers on them. I also added a modern 14mm master cylinder, stainless steel lines from slingshot and phenolic pistons from Godffrey. It does approach modern bike stopping power now. You can two finger it for sure and is a huge improvement over stock.

[sixthwisconsin]

Just added the 750

[Godffery]

Got'em.  Thanks Man, they both look great!