Author Topic: a thinner,lighter repro front brake rotor work on a CB350/400F front wheel ? (Read 8262 times)

grcamna2 · « **on:** October 27, 2016, 06:38:15 AM »

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 · « **Reply #1 on:** October 27, 2016, 06:53:19 AM »

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 · « **Reply #2 on:** October 27, 2016, 07:04:35 AM »

Quote from: flybox1 on October 27, 2016, 06:53:19 AM

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 · « **Reply #3 on:** October 27, 2016, 01:30:22 PM »

Quote from: flybox1 on October 27, 2016, 06:53:19 AM

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 · « **Reply #4 on:** October 27, 2016, 01:35:34 PM »

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 · « **Reply #5 on:** October 27, 2016, 01:53:31 PM »

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

grcamna2 · « **Reply #6 on:** October 27, 2016, 02:55:30 PM »

Quote from: Bodi on October 27, 2016, 01:53:31 PM

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 · « **Reply #7 on:** October 27, 2016, 03:35:23 PM »

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

slikwilli420 · « **Reply #8 on:** October 27, 2016, 03:36:46 PM »

Quote from: Bodi on October 27, 2016, 01:53:31 PM

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 · « **Reply #9 on:** October 27, 2016, 04:18:15 PM »

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 · « **Reply #10 on:** October 27, 2016, 04:45:56 PM »

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 · « **Reply #11 on:** October 27, 2016, 04:49:41 PM »

Quote from: 754 on October 27, 2016, 04:45:56 PM

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 · « **Reply #12 on:** October 28, 2016, 08:01:53 PM »

Quote from: Bodi on October 27, 2016, 01:53:31 PM

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 · « **Reply #13 on:** October 28, 2016, 09:07:48 PM »

Quote from: Godffery on October 28, 2016, 08:01:53 PM

Quote from: Bodi on October 27, 2016, 01:53:31 PM
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 · « **Reply #14 on:** October 29, 2016, 03:45:59 PM »

Quote from: grcamna2 on October 28, 2016, 09:07:48 PM

Quote from: Godffery on October 28, 2016, 08:01:53 PM
Quote from: Bodi on October 27, 2016, 01:53:31 PM
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 · « **Reply #15 on:** October 29, 2016, 04:03:51 PM »

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

Godffery · « **Reply #16 on:** October 29, 2016, 08:22:03 PM »

Quote from: grcamna2 on October 29, 2016, 04:03:51 PM

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

Oh, ok. Got that and just replied.

grcamna2 · « **Reply #17 on:** October 29, 2016, 08:28:57 PM »

Quote from: Godffery on October 29, 2016, 08:22:03 PM

Quote from: grcamna2 on October 29, 2016, 04:03:51 PM
I'm still waiting for a reply to my last email Jeff,thanks.
Oh, ok. Got that and just replied.

thanks

RAFster122s · « **Reply #18 on:** November 03, 2016, 01:17:13 PM »

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 · « **Reply #19 on:** November 03, 2016, 05:36:09 PM »

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

grcamna2 · « **Reply #20 on:** November 03, 2016, 05:50:27 PM »

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 · « **Reply #21 on:** November 03, 2016, 08:15:02 PM »

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 · « **Reply #22 on:** November 04, 2016, 07:25:49 AM »

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 · « **Reply #23 on:** November 04, 2016, 12:01:30 PM »

Quote from: sixthwisconsin on November 04, 2016, 07:25:49 AM

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 · « **Reply #24 on:** November 04, 2016, 12:32:30 PM »

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Author Topic: a thinner,lighter repro front brake rotor work on a CB350/400F front wheel ? (Read 8262 times)