Honda CB750 Sandcast

The Restoration Shop => Lighting Systems and Chassis Electrical => Topic started by: Steve Swan on February 17, 2010, 07:51:26 pm

Title: Early LH Horn Wire Sheath
Post by: Steve Swan on February 17, 2010, 07:51:26 pm

Posted by kerrycbx "Guest"

Hi all,
Happy new year to everybody. Anybody want to offer an opinion as to which is the correct colour sheath that covers the wires on the LH wire outlet horn fitted to sandcast up to VIN 3850. I have one listed on ebay item # 4601098828
I have 3 horns (well 4 really but the wife won't let me sell #3  hee hee hee) One with a black sheath and one with a grey sheath. Let's hear it  KPster

Title: Re: Early LH Horn Wire Sheath
Post by: 736cc on February 17, 2010, 07:52:51 pm

One of my early sandcasts (around 2500) had a LH grey horn (I forget the color of its wire sheath), and it was definately the original horn. All the rest had black plastic and sheathing. Some advertising pics from 1969 show the grey horn on sandcasts.

Title: Re: Early LH Horn Wire Sheath
Post by: elisent on February 17, 2010, 07:54:58 pm

I have grey, almost a tan color on both my sandcast and 71 450. I have black on an original 70 KO750. I've wondered about this also.

Title: Re: Early LH Horn Wire Sheath
Post by: 736cc on February 17, 2010, 07:55:28 pm

Some magazines color covers from 1969 show the grey horn on early bikes. Also spotted a red plug key in an ad. This SUPERB site shows examples of those pics.

Title: Re: Early LH Horn Wire Sheath
Post by: kp on February 17, 2010, 07:56:03 pm

Thanks Eli & Andy
Anyone else got info on this subject. KP

Title: Re: Early LH Horn Wire Sheath
Post by: Steve Swan on February 17, 2010, 07:56:38 pm

Hello Fellows,

In reference to parts suggested to be "Original" to Early & Late Production sandcast machines:

Regaurding horns, to date, i have contacted 5 individual members owning VIN's 175 to 325. These 5 machines APPEAR to all have original horn from date of manufacture, early 1969.

I would like to thank these 5 members, i would not be able to share this information without their help.

Citing the following as examples to support this statement: "Factory Parts Manuals should not be relied on as sole source of reference to determine what part is or is not "original" to bike."

A number of cases can be noted in Parts Manuals where actual part number does not change when the acutal part changes or part number does not indicate a change in part was made.

Seats for example -

1. Per 69.7 Parts Manual, pn is 77200-300-020A.

2. Per, 1st Ed., Parts Manual, published February, 1971, CB750-CB750K1 - same part number (77200-300-020A) used for seat on machines CB750-1000001 - 44649

It is known 2 variants of seat pans exist. Early Production seat pans had fewer holes in the metal base than Late Production seat pans. Unknown (to me) at what VIN seat pan with fewer holes was changed to more holes.

Other examples of same part number used on actual different parts include, upper brake hoses, RH kill starter/kill switches, fork top bridges & oil lines. These parts all share same part number, Early Production machines used a different part than Late Production machines. (unknown to me at Exactly what VIN these parts changes occured.)

Going back to horn topic:

Appears 3 different types of Left Hand horns exist:

1. Gray plastic body horn w/ gray wire sheath.
2. Black plastic body w/ gray wire sheath
3. Black plastic body with black wire sheath

Horns "original" to date of motorcycle manufacture all appear to have numbers stamped in plastic; numbers not printed in ink ("inked" print horns are later date of manufacture & OEM Honda replacement part, not "original" to date of manufacture.)

Gray plastic body horns are pictured on Early Production bikes, in numerous magazine articles and Factory literature. It is ASSUMED these Gray body horns could have been used on VIN's before 175 and PERHAPS not afterwards.

All 5 machines from VIN 175 to 325 have a black plastic body horn with black wire sheath. It is known VIN 1292 has a gray body horn with a gray wire sheath. (To date, on a motorcycle, have not noted a LH black plastic body horn with gray sheath.)

It is also known, "Running Production Changes" were implemented on the Factory Assembly Line. That is, various parts from other models such as the 305, 350 & 450 were used on the 750 during Early Production run. It is known, 305, 350 & 450 models used gray plastic body horns.

Referencing the above Parts Manuals for horn part numbers, 2 pn's are noted; 38100-300-013 & 38100-300-023. The K1 Parts Manual indicates the "013" horn used to VIN CB750-1003950 & the "023" horn used beginning at CB750-1003951. It is ASSUMED the change in pn SUGGESTS a shwitch from LH mount horn to RH mount horn. Frame number 50100-300-050B supports this statement, as this pn is used from CB750-1000001 through CB750-1003950. Part number 50100-300-060B is used beginning at VIN CB750-1003951.

To date, i have not found (yet) evidence to support horn parts numbers suggest a gray or a black wire sheath.

Finally, i am not aware any PRODUCTION LH mount horn or frame used anything but a flat bracket to mount horn to frame. Again, this is an example of where the Parts Manuals are not reliable as a sole source of reference. The 7.69 & the K1Parts Manuals both indicate a mounting bracket that has two 90 degree bends, NOT a flat bracket as found on Early Production machines.

To date, i am not aware (yet) of any Production LH mount horn using this "double bend" bracket. It is also known Honda Factory literature, such as Owner's Manuals & Factory Repair Manuals used photographs to DEPICT a concept. And, these photgraphs used to depict a concept frequently were pictures of Early & Late Pre-Production machines.

In closing, i appreciate the debate brought about by the "horn advertised recently on Ebay." There is only one piece of evidence to possibly suggest this horn not to be a correct and/or original horn. The horns on the 5 machines noted above all have the green wire on the bottom and black wire on top. The horn recently on advertised on Ebay has the black wire on bottom & green wire on top. Other than not having a mount bracket, the horn on Ebay, fits all tests proposed within this email, to be accepted as an "original" and/or "correct" horn.

Finally, i do not consider myself an authority or an expert. I will state i know more than most and not as much as some. My research, assumptions and theories on horns (or any other parts) are most welcome to debate. I don't mind being "taken to school." Sometimes, there's no better way to learn.

There are a number of minor details (some not mentioned in this email) on Early & Late Production sandcast bikes that can be argued whether or not are "original" or "correct" for the Early Production machines. I am not aware, with 100% accuracy, a global statement can be made, citing one single reference (such as the Parts Manual) that would say with absolute authority a particular part is "original" or "correct."

What fun !

Steve Swan

Title: Re: Early LH Horn Wire Sheath
Post by: Bickle on February 17, 2010, 07:57:19 pm

That was a great post...Keep up the great work Steve

Title: Re: Early LH Horn Wire Sheath
Post by: 736cc on February 17, 2010, 07:57:43 pm

and I thought horns just go beep  ::)

Title: Re: Early LH Horn Wire Sheath
Post by: CB750faces.com (Lecram) on February 03, 2011, 06:23:26 pm

I have cleaned the horn I found on my 1971 K1 and found that the chrome cover had been rotated. After mounting the chrome cover in the correct position, it seems that the wire hole of the chrome cover is now in the right position.

Is this the right horn for an early CB750 or not? Who knows?

(https://lh5.googleusercontent.com/_Iwudks3e4io/TUszZiY7AII/AAAAAAAAD3c/j1tPzz20Uec/s800/grey_horn_1.JPG)

(https://lh5.googleusercontent.com/_Iwudks3e4io/TUszZ9QeP1I/AAAAAAAAD3g/-kZ82k4hxb8/s800/grey_horn_2.JPG)

Title: Re: Early LH Horn Wire Sheath
Post by: kp on February 04, 2011, 04:14:20 am

Mark with an arrow on the photo where the drain hole within the chrome cover is located KP

Title: Re: Early LH Horn Wire Sheath
Post by: CB750faces.com (Lecram) on February 04, 2011, 04:28:04 am

Hi Kerry,

Exactly the position where the wires come out on the picture. At ca. 300 degrees

(https://lh5.googleusercontent.com/_Iwudks3e4io/TUvGihdXPrI/AAAAAAAAD38/juWVcI-rRng/s912/grey_horn_3.JPG)

Title: Re: Early LH Horn Wire Sheath
Post by: Riccardo on February 04, 2011, 04:22:47 pm

Marcel,

post please the photo with the exact position of the drain hole.

From my experience:
-the small balck stay is the same in the lefty and rightly horns, infact it's possible roteate the stay;
-the chrome cups are differents (for the L and for the R horn) because changes the position of the rectangular hole for the wires;
-the exit wire is ever oriented to the center of the frame of the bike, were is the natural position of the harness wires dedicated to the horn;
-the alloy body-frame, solid with the plastic, has the FIX positions for the chrome cup, impossible to roteate;
-the drain hole is at 180 degree.

Title: Re: Early LH Horn Wire Sheath
Post by: CB750faces.com (Lecram) on February 04, 2011, 06:22:14 pm

Sorry, i didn't read the question of Kerry well.

The drain hole is at 180 degrees indeed. With the drain hole pointing downwards, the wire hole is at the left side, ca. 300 degrees.

The bracket is the same of the RH horn, although the bracket of the LH is a little bended. I can't imagine that it has bended by accident.

To compare the LH to the RH, I put both together.

Drain hole at bottom:
(https://lh3.googleusercontent.com/_Iwudks3e4io/TUyH9sTcvLI/AAAAAAAAD4E/ymnbTRotneA/s912/grey_horn_4.JPG)

For comparison:
(https://lh6.googleusercontent.com/_Iwudks3e4io/TUyJTo-vX4I/AAAAAAAAD4Y/s9ywsIHx9ms/s912/grey_horn_5.JPG)

(https://lh6.googleusercontent.com/_Iwudks3e4io/TUyJUCKd0HI/AAAAAAAAD4c/4wlvYyZCrVw/s912/grey_horn_6.JPG)

(https://lh3.googleusercontent.com/_Iwudks3e4io/TUyJUkoUgdI/AAAAAAAAD4g/xzNfI-MXrig/s912/grey_horn_7.JPG)

Title: Re: Early LH Horn Wire Sheath
Post by: kp on February 04, 2011, 06:37:16 pm

Marcel,
Yes, this is the same horn as a sandcast LH horn should be. The drain hole and wire exit are correct. This is also the same horn as fitted to the early CL450s  ;) KP

CL450 HORN

(http://cb750k0only.com/coppermine/albums/userpics/10003/Horn_CL450%7E0.jpg)

Title: Re: Early LH Horn Wire Sheath
Post by: CB750faces.com (Lecram) on February 04, 2011, 06:45:24 pm

So I am the lucky owner of a sandcast grey horn  ;D

I wish that I was a Sandcast owner .....

Title: Re: Early LH Horn Wire Sheath
Post by: Riccardo on February 04, 2011, 06:47:02 pm

Quote from: kp on February 04, 2011, 06:37:16 pm

Marcel,
Yes, this is the same horn as a sandcast LH horn should be. The drain hole and wire exit are correct. This is also the same horn as fitted to the early CL450s  ;) KP

CL450 HORN

(http://cb750k0only.com/coppermine/albums/userpics/10003/Horn_CL450%7E0.jpg)

For my 737 i purchased a NOS for Honda cb450, perfect!

Title: Re: Early LH Horn Wire Sheath
Post by: hondasan on February 05, 2011, 02:22:16 pm

More trivia.....
Early CB250  twins used a horn with a "gray" body, but different stay.
The horn from a 350/4 honda is effectively a left hand sandcast horn (black body, chrome cover with drain hole at the bottom and cable exit at upper left) but again with a different stay - replace the 350 stay with a 750 one  to convert.
These at least provide ways of re-creating a left side horn if missing.

As per Steve's previous message, all the left hand horn sandcasts I have seen have black body / black sheath. This includes my two bikes (#'s 302 and 1120), and the NOS left side horn I have.
Anything else is either one of those mythically very rare factory fitted ones, or perhaps not original to the bike. :-\

Cheers - Chris R

Title: Re: Early LH Horn Wire Sheath
Post by: Marcello Tha on July 21, 2013, 03:54:48 pm

Could someone confirm or not my observation, that K0 Horn had no cast marks in the places showed in the pictures,  and K1-K6 had these marks?

Thanks.

Marcello