Author Topic: I have a 1969 cb750 with a broken carbs mount bracket  (Read 6715 times)

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Offline Hondawggie

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I have a 1969 cb750 with a broken carbs mount bracket
« on: June 21, 2010, 10:23:48 PM »
I bought a set of carbs off eBay for my 1969 cb750 and
(ahem) the seller didn't put enough packing and the mounting
bracket for the 4 carbs snapped between carbs #2 and #3
somewhere in transit to me.

I looked on the parts list I have for the 1969 cb750 -- and
I thought I was bummed today when I opened the box
and the carb bank came out in 2 pieces -- now I find that the dang
(broken) mounting bracket HAS NO INDIVIDUAL PART NUMBER.

I know from the parts list that Honda switched away from
my "4 cables, 1 cable-per-carb" setup pretty quick according
to the parts list -- it looks like starting with the 1970 model
year, Honda switched to a pulley-and-mechnical-arm system
to lift the 4 carb slides when the throttle is opened.

So here I am, pretty dumbfounded.  No part number for my
bracket.  And NO INTERCHANGEABILITY with another model
year!  $hitt.

Does anyone know of an aftermarket supplier for this bracket?


I have a photo of the situation here.  By the way, the seller's error
was
1) not packing them in a big enough box and lots of soft-yet-firm padding
    with a built-in assumption the box WOULD BE DROPPED

2) and most important -- the seller neglected to recognize that a pretty thin,
     41-year-old piece of cast aluminum that was subjected to much engine heat
     then left to get very brittle in 41 years -- needed a box BIGGER THAN THE CARB BANK.
     The brown paper you see in the photo below is all that was wrapped around the length
     of the carb bank, and the bank of carbs barely fit in the U.S. Priority Mail box.
     To his credit he *did* use paper packing at either end of the bank, but $hitt,
      with the weight of the 2 heavy carbs on either side of the bracket's centerpoint --
     and no lengthwise non-bending bracing/packing of some sort along the length of the bank
     to prevent flexing in case of being dropped -- the very thin bracket
      was just BOUND to break.  Even without the 41-year-old-heated-and-brittleness that
      has affected the bracket, any intro physics class gives you enough 'physical intuition'
    to realize if it's dropped, this thin 4-carbs bracket will SNAP.  The bracket looks
   thicker in the photos below than it really is.  It is THIN.  I'm super disappointed.
  






Swoop

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #1 on: June 22, 2010, 02:47:55 AM »
They come up on ebay from time to time. It is a common problem. Someone was selling high quality repro's....I got one....but I haven't seen them for awhile.
It can also be welded.

Steve

Offline 754

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #2 on: June 22, 2010, 08:47:36 AM »
Try making one out of 1/4 inch aluminum..6061. That ought to hold up. I think the original is cast and not as strong. even weaker in them relieved areas..

 I used to have one here from way back..when I split a set of those to put on a 350 twin.. never could find it though...if I did it already has dibs on it..
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Offline Roach Carver

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #3 on: June 22, 2010, 08:52:01 AM »
I have one like that. very common. What are the odds that it was broken before he ever shipped it?

Offline scottly

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #4 on: June 22, 2010, 07:50:03 PM »
You might send a PM to fellow member big-jim: he does precision welding, and may be able to help.
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co425

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #5 on: June 22, 2010, 08:48:21 PM »
I do not think they are weldable.

It is very common for them to break when removing them. It was more than likely broken before they were shipped. Your best bet is eBay or machine your own from 1/4 6061 like I have done in the past.

Online Terry in Australia

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #6 on: June 22, 2010, 09:02:11 PM »
You can weld 'em no problems. Clyde Ikin in Sydney had his welded and had the welder fill in the casting depressions between the webs to give them more strength.

I bought a set of K0 carbs from a member here and they were "busted in transit" (probably more likely when he pulled them off the bike) but I bought a repro bracket from a guy in Canada, machined from 6061-T6 plate, and he even stamped the part # into the end of the plate, like the original. He was advertising them on EBay, but I haven't seen them for awhile.

I think one of the guys here machined down a later CB750 carb bracket, it'd probably work ok, just not look as neat. Cheers, Terry. ;D
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Offline lucky

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #7 on: June 02, 2012, 11:59:13 PM »
I do not think they are weldable.

It is very common for them to break when removing them. It was more than likely broken before they were shipped. Your best bet is eBay or machine your own from 1/4 6061 like I have done in the past.

Of course it is weldable!!!

Offline 754

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #8 on: June 03, 2012, 09:14:24 AM »
 There was a Cycle salvage place near Edmonton AB had made some. might be called Edmonton Motorcycle salvage or similar.. if the owners name is Gilles..thats ther right one..
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Lost quite a few CB 750's along the way

Offline camelman

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #9 on: June 03, 2012, 09:29:00 AM »
I just bought a set of these carbs off a fellow member which were welded. I have not mounted them yet to see if the weld is string enough, but it sure looks like a quality weld.
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Offline lucky

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #10 on: June 03, 2012, 12:33:01 PM »
I have one like that. very common. What are the odds that it was broken before he ever shipped it?

did you see the soft package?
It got broken when other stuff was stacked on top of it.
El cheapo package to save a dime.
It should have been in a box! End of story.
So no a vintage part is broken because someone wanted to save $3.00 while
they got maximum profit.
I would definitely write a Ebay message and let them know what their cheapness cost the customer.
« Last Edit: June 03, 2012, 12:35:16 PM by lucky »

Offline 754

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #11 on: June 03, 2012, 02:20:12 PM »
 Cant leave feedback after 23 months.. really..

 Myself If I ran those carbs, I would make a BILLET replacement, and stash my original.. oh hey, I already have an original stashed..
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline bryanj

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #12 on: June 03, 2012, 11:53:33 PM »
Has nobody thought that as they are individual cables they would probably run OK if fitted as they are?
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Online Terry in Australia

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #13 on: June 04, 2012, 12:30:28 AM »
Has nobody thought that as they are individual cables they would probably run OK if fitted as they are?

Yep, we all thought that first Bryan, but then we all went naaaaaaaaa............. ;D
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Offline lucky

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #14 on: June 04, 2012, 02:16:08 AM »
Cant leave feedback after 23 months.. really..

 Myself If I ran those carbs, I would make a BILLET replacement, and stash my original.. oh hey, I already have an original stashed..

Would you be interested in selling your 754? I need one for my set of 1969 carbs.
I'm serious.

Offline gonzobrian

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #15 on: June 04, 2012, 04:44:53 AM »
I also have a set with the same break.  I got a replacement set a while back on ebay.  Eventually I am going to try to repair my original one using a product called alumiweld.  They sell it a Harbor Freight probably Lowe's etc.

http://www.alumiweld.com/

Offline lucky

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #16 on: June 04, 2012, 05:38:31 AM »
I also have a set with the same break.  I got a replacement set a while back on ebay.  Eventually I am going to try to repair my original one using a product called alumiweld.  They sell it a Harbor Freight probably Lowe's etc.

http://www.alumiweld.com/

The Alumiweld is a very poor choice. Get it TIG welded.
I know from experience. That product is very difficult to use.

Offline lucky

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #17 on: June 04, 2012, 05:40:40 AM »
I also have a set with the same break.  I got a replacement set a while back on ebay.  Eventually I am going to try to repair my original one using a product called alumiweld.  They sell it a Harbor Freight probably Lowe's etc.

http://www.alumiweld.com/

The Alumiweld is a very poor choice. Get it TIG welded.
I know from experience. That product is very difficult to use.


Offline 754

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #18 on: June 04, 2012, 07:46:00 AM »
 I dont want to sell it, because I have 2 sets of KO carbs(one is a buddies.
 I figure if we are using them and the rubbers are a bit hard they could break, on install. We should post up the measurements or get some CNCed. with My manual mill, way too much work to make a finished piece.
Maker of the WELDLESS 750 Frame Kit
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Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline ekpent

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #19 on: June 04, 2012, 07:57:06 AM »
I thought this member if I remember correctly has made a custom plate for his within the last year or so ?? ,surprised he has not piped in.  http://forums.sohc4.net/index.php?topic=107929.0

Offline 70CB750

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #20 on: June 04, 2012, 07:58:26 AM »
Try making one out of 1/4 inch aluminum..6061. That ought to hold up. I think the original is cast and not as strong. even weaker in them relieved areas..


Thats what I did. Broke it myself actually, made a replacemnt from rolled bar. Not hard to do, all you need is a hole saw and drill press and hacksaw and file to shape it.
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Offline phil71

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #21 on: June 04, 2012, 09:04:27 AM »
With no bellcrank and throttle shaft, you oughta be able to just run 'em as is.

Offline Don R

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #22 on: June 04, 2012, 09:14:56 AM »
I broke mine getting it off with the old rock hard boots. Ran it broken for a bit then tig welded it myself. I let a shop do some carb work for me,  they broke it again. I welded it again and do my own carb work now.  I wouldn't mind buying a reasonably priced plate replacement though.
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Offline thep1pe

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #23 on: June 04, 2012, 10:13:45 AM »
There is a carb bracket on Ebay item No 130580280314
It's on the German site though. Maybe the one you need. He says to email for shipping quote. You may have to change your Ebay setting to German though to see it. I have bought stuff off him before with no probs, I'm in the UK though but should be ok for usa.

Offline Magilla

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Re: I have a 1969 cb750 with a broken carbs mount bracket
« Reply #24 on: June 04, 2012, 12:24:45 PM »
Where are you located?  I have two motorcycle boneyards near me.  If y need me to I can go buy one for you and mail it to you.  Once you get it you can send me a check for it.  Let me know it that helps you out. 

Also if there are major differences in this part for year to year let me know is I can find the right one. 
1972   Honda CB350
1972   Yamaha 500
1982   Yamaha 650
1988   Harley Sportster 883
1983   HD FXR Shovelhead
2003   HD Heritage Softail
2006   Victory Vegas Jackpot
1980   Honda CB650
1976   Honda CB750K
1982   Honda CB750
1964   Honda CA95
1982   Kawasaki 550
1974   Honda CL360
1975   Suzuki GT550
1981   Honda CB750
1981   Honda CB750
1970   Norton Commando
1972   Yamaha U7E
1970   BMW R50/5
1976   Honda CB750F