Author Topic: Million dollar question (Read 5051 times)

greenjeans · « **on:** March 20, 2008, 07:19:10 PM »

1972 CB750K

Does anybody know (or know how to find out) if Honda made this part (#2 caliper mount) as a mirror image?
ie for the right side. Dual disc conversion. The fork tube lowers are mirror images of each other.
The other part of the caliper mount (#1) is symetrical - it can be used on both sides. Their race bikes had dual discs.
Is it a part that could possibly be found and ordered through Honda? Honda racing ? Aftermarket?

Anyway to figure out a part number ?

I know they're out there - check this out:

I know it's the left side, but you can see through to the right & it's exactly what I need.....
Those fork lowers, calipers and mounts are just like mine (only much, much prettier)

MRieck · « **Reply #1 on:** March 20, 2008, 07:41:34 PM »

Quote from: greenjeans on March 20, 2008, 07:19:10 PM

1972 CB750K

Does anybody know (or know how to find out) if Honda made this part (#2 caliper mount) as a mirror image?
ie for the left side. Dual disc conversion. The fork tube lowers are mirror images of each other.
The other part of the caliper mount (#1) is symetrical - it can be used on both sides. Their race bikes had dual discs.
Is it a part that could possibly be found and ordered through Honda? Honda racing ?

If I remember correctly Yosh made them.....a long..long....long......long time ago. I read about a factory SS version (once again subject to memory) that had a mirror image. That's like 35 years ago.

kghost · « **Reply #2 on:** March 20, 2008, 09:26:36 PM »

Yeah thats a K2....they changed the next year.

They may have been on earlier ones I can't confirm..I do know I have two K2's with that exact bracket.

Have you thought about just getting 2 73 and up brackets?

They bolt to the leg same as yours....and the calipers fit either one....

mystic_1 · « **Reply #3 on:** March 20, 2008, 10:46:09 PM »

Quote from: kghost on March 20, 2008, 09:26:36 PM

Have you thought about just getting 2 73 and up brackets?

They bolt to the leg same as yours....and the calipers fit either one....

I don't think the 73 and later brackets will bolt up to the pre-73 fork lets, the mounting lugs on the lower fork are different.

Here's a pic of the two different styles of arm that I found in another thread:

In addition to the mounting bolt pattern, notice that the two arms are at slightly different angles relative to their hinge pins.

Another thread I found indicates that yes, a factory bracket of was made for a right-side caliper mount on the 69-72 models. It also mentions the Yoshi brackets and a couple of other old sources.

mystic_1

bryanj · « **Reply #4 on:** March 20, 2008, 11:33:26 PM »

The only "mirror image" brackets made came in the RC kit or from Yoshimura and were made from something exotic like titanium or magnesium, Aint seen one of those in 30 years!!!!

i am told you can mill down one of the bosses and ft a spacer on another bolt hole to alter one to fit but i have not actualy seen or done this

ttr400 · « **Reply #5 on:** March 20, 2008, 11:51:04 PM »

Anybody willing to send that complete bracket set up to me, and I will machine some. Oh, and you will get one for free...

Kevin

kghost · « **Reply #6 on:** March 20, 2008, 11:56:56 PM »

Quote from: mystic_1 on March 20, 2008, 10:46:09 PM

Quote from: kghost on March 20, 2008, 09:26:36 PM
Have you thought about just getting 2 73 and up brackets?

They bolt to the leg same as yours....and the calipers fit either one....

I don't think the 73 and later brackets will bolt up to the pre-73 fork lets, the mounting lugs on the lower fork are different.

Here's a pic of the two different styles of arm that I found in another thread:

In addition to the mounting bolt pattern, notice that the two arms are at slightly different angles relative to their hinge pins.

Another thread I found indicates that yes, a factory bracket of was made for a right-side caliper mount on the 69-72 models. It also mentions the Yoshi brackets and a couple of other old sources.

mystic_1

I believe they do....one of the bolt holes on the K2 leg actually mounts to the fender cross brace and NOT to the fork tube.

In place of the actual bracket mounting to the fork tube in ONE location the fender mounts to it.

This puts the bracket at the correct angle.

I will confirm this tomorrow and attempt to get some decent pictures of both.

As far as I can tell the cut off would be around serial number 2093731.

Honda lists the same fork after that...as part number 51500-341-701/702

Head · « **Reply #7 on:** March 21, 2008, 12:55:59 AM »

About two years ago www.yamiya750e.com/ sold them for $250. but I don't see them now,
Bracket and arm. I made the spacers for both type brackets and they are working well!
Maybe some pic's later today. 4 am I to tired.
Head

dustyc · « **Reply #8 on:** March 21, 2008, 01:09:02 AM »

Quote from: ttr400 on March 20, 2008, 11:51:04 PM

Anybody willing to send that complete bracket set up to me, and I will machine some. Oh, and you will get one for free...

Kevin

If you're talking about the later one, consider it done. It's boxed and ready to send.

ttr400 · « **Reply #9 on:** March 21, 2008, 01:37:05 AM »

Dusty,

PM sent.

Do you have pics of the later one.?

Kevin

dustyc · « **Reply #10 on:** March 21, 2008, 03:16:06 AM »

Just checked back in on this post. I'll snap some pics and post them. -Got your address and will ship them in a couple hours. -As soon as we verify they're what you're after.

Thanks,
Dusty

City Boy · « **Reply #11 on:** March 21, 2008, 04:34:29 AM »

Honda did offer the right side bracket as a CR part.I bought one back in the day.Would be very rare to find today I think.Dont recall the # but last 3 digits would be 970.

greenjeans · « **Reply #12 on:** March 21, 2008, 07:55:03 AM »

Kevin,
I can send you exactly what's in the pic if that's what you're talking about....
Do you have access to a 3D router or something ? What's the process ?
What kind of time frame are you thinking ? At the very least I'd owe you a
case of your favorite beverage.....

And post a link to more pics of that bike in your avatar...

greenjeans · « **Reply #13 on:** March 21, 2008, 08:13:31 AM »

Anybody have any Honda shops that could come up with a part number ? My local shop have undergone a changing of the guard....Nobody in there was alive when these things were made.... It was a monumental struggle just to order a piston/caliper seal last week.

Here's more pics of the fork lowers (mounting points) and the asymetrical fender mount

ttr400 · « **Reply #14 on:** March 21, 2008, 10:04:26 AM »

Thanks Greenjeans, PM sent.

Thanks to Dusty and Greanjeans I will be able to make these parts from the samples that are going to be sent to me.
The process to enable the machining of these parts is first I must measure the part/parts, if a complicated part I send it out to be laser measured to get accurate dimensions. then I would use these dimensions and produce a 3D drawing in mastercam ready for machining.
Various fixtures would also have to be machined to hold the part in the vice. Looking at the pics posted I would say that #2 bracket would be 3 operations in a CNC vertical mill.

Timing is a hard one to predict, probably around 4 weeks. just depends on how busy the machines are.

To see more pics of my 400F racer and lots more of what I do check out my website.

Kevin
www.ttr400.com

mystic_1 · « **Reply #15 on:** March 21, 2008, 10:31:30 AM »

Just to be clear, we're looking for a mirror image of the pictured Part #2. The pictured part fits the left side fork leg, we need one that fits the right side.

Geeto67 stated in THIS THREAD that he had one of the right-side parts, perhaps he could be talked into offering his up temporarily as a pattern.

This raises an interesting question - in the stock single-disc arrangement, the fender mounts to the brake arm bracket on the left side, and directly to the fork leg on the right side. As pictured above, the fender bracket is asymmetrical. So if we simply mirror the brake arm bracket, we'll need to figure out a new way to mount the right side of the fender bracket.

mystic_1

greenjeans · « **Reply #16 on:** March 21, 2008, 10:46:23 AM »

Yep, right side is what we need.
Kevin obviously has access to heavy-duty software and equipment. So I'm hoping (Kevin, correct me if I'm wrong) that
once he gets the part drawn in his software, he will be able to flip/mirror it before he sends it to the CNC machine.
Then we can start worrying about the fender mounts - that would be a bit easier to fabricate than the bracket.

You guys be sure to check out Kevin's site.... great stuff.

Geeto67 · « **Reply #17 on:** March 21, 2008, 11:53:26 AM »

Quote from: mystic_1 on March 21, 2008, 10:31:30 AM

Geeto67 stated in THIS THREAD that he had one of the right-side parts, perhaps he could be talked into offering his up temporarily as a pattern.

This raises an interesting question - in the stock single-disc arrangement, the fender mounts to the brake arm bracket on the left side, and directly to the fork leg on the right side. As pictured above, the fender bracket is asymmetrical. So if we simply mirror the brake arm bracket, we'll need to figure out a new way to mount the right side of the fender bracket.

mystic_1

Actually I have 2. I have a 970 one which looks to be magnesium on a CR750 front end I bought (I checked it last night) and I have a loose one that also looks to be magnesium has never been used.

I am willing to offer it up as a pattern but I am going to need some serious assurances that I am going to get it back.

But, before we go crazy manufacturing parts out of thin air - lets stop for a second and ask if this is really necessary. At $250 a pop (which is what that japanese firm was charging) I can get a really nice 73-76 K front end and spare caliper.

One part that would make the dual disc conversion more user friendly is to reproduce the sandcast speedo drive that allows one to run dual disc and the stock speedo drive. there is probably a bigger market in k0 restorers as well...

....It is also a part I could use to convert my own K5 to dual disc.

City Boy · « **Reply #18 on:** March 21, 2008, 01:20:09 PM »

Greenjeans,I am not sure about mounting the stock fender to the right side bracket.I mounted a Kawasaki H1R fiberglass fender to my unit and drilled the required holes in it for mounting.Geeto,the 970 bracket I have is alum.,this part would be same as that offered in CR race kit .Your mag. piece would be a "works" part I think.

Geeto67 · « **Reply #19 on:** March 21, 2008, 01:56:52 PM »

could be aluminum....I took it to be mag because of some dark spots on the part (magnesium corrodes black). The loose one is definatly much lighter than a stock alloy one so I am betting that is mag. I really don't have any other way of testing them.

turboguzzi · « **Reply #20 on:** March 21, 2008, 02:04:03 PM »

Hey Geeto

Just hold it above an open flame, if it burns, producing a big flame, then it's magnesium!

:-)

A Happy Easter to all

TG

greenjeans · « **Reply #21 on:** March 21, 2008, 02:10:27 PM »

No need, Kevin can use the existing part and most likely flip it in his software.
I'm going to be using an aftermarket reproduction fender. Will have to fabricate mounts anyway -easy enough. If I hadn't already rebuilt and refinished/polished the forks, I'd go for newer style mounts/fork lowers etc. Honestly, I thought it would be easier to find an existing part. It's very lucky indeed to have this site where I can get in touch with people that have the know-how and equipment to fabricate one.

Also, I really like the look of the finned calipers.

City Boy · « **Reply #22 on:** March 21, 2008, 02:32:12 PM »

Greenjeans,sounds like your spare is mag, and doesnt surprise me.I once bought a "works" 750 front end from a guy at AM. Honda.It had 4 bolt cap mag. lower legs and titanium upper legs with a ti. lower stem.I resold it as it was much shorter than stock and must have fit a much different frame.I do have installed the CR kit forks,which appear stock except are 1" longer than stock and chromed full length.

lordmoonpie · « **Reply #23 on:** March 22, 2008, 02:20:42 AM »

I've got a right side version of this bracket - took the original left side version and had a mirror made of it for my CR replica brake setup. The company I used will do this with no issues, they even made me a mirror image shift drum so I can run a japanese race replica backward facing gear lever and still have a road pattern box, so I don't use the linkages like the Daytona bikes.

The company is called Minnovation and they're on the right side of the pond of course

Contact them through the website - www.minnovation.co.uk, I think it's Martin you need to speak to.

Mind you - when you have this all machines up, the trauma it is to get a wheel in and out is amazing if you're running wm3 front race tyres. I have to leave the disks dangling around the spindle just to get the wheel in and build one caliper up on the mount after the wheel is in!!

News:

Author Topic: Million dollar question (Read 5051 times)