Author Topic: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!  (Read 2450 times)

Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #15 on: September 18, 2023, 04:16:48 PM »
Okay I managed to dismantle the carbs & the shaft after drilling out the retainer rivet though my drill went very slightly off center as I do not have a pillar drill.

I did notice that the brass bearing on that side is not a full one like the other end of the bracket - see photo. Can't understand why it does not have a full bearing with a hole for the rivet. If you zoom in you can see it's closed to half a brass insert.

The shaft has cleaned up a tad - the rust is restricted to the outside area of the shaft not where the bearings & various parts fit. Not sure what to do with it tbh.

The centre quadrant type part is pretty clean but it's only just holding together tbh by two rivets - it does not appear to be out of shape or damaged likewise the throttle clamp looks okay - the two bolts that hold it in place with the fuel pipe bracket were such that when loosed it was straight - might have been just tightened up wonky or the split quadrant put some side pressure on the throttle cable action.

.bearing end  rivet by Macabe Thiele, on Flickr

.throttle shaft by Macabe Thiele, on Flickr


Honda CB500 K1 (new pit dug out ready)
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Offline Oddjob

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #16 on: September 18, 2023, 04:48:42 PM »
That's not good Ted. The bronze bush appears to have broke in half. If it was meant to be like that the edge would be clean but that's jagged and you can clearly see where it's broken off from the other part. That part I suspect came adrift when the shaft was removed, possibly when the damaged area of the shaft was drawn through it. Any sign of the missing piece?

As for the shaft, not a great deal you can do with that TBH, whatever you do will come back eventually. Only option is to get it replated, trouble is with what. If you go with BZP you'll need to remove whatever is left of the original finish I'd imagine, plus you then have the problem of if you overplate it the shaft won't fit through the hole where the bush is. When I had my last 2 shaft hard chromed they didn't grind down the parts of the shaft where the 2 woodruff keys fit. They did grind them down but just not as deep as the rest of the shaft, mainly I think because the edges were chipping (which was evident on all the shafts where there were holes in the metal, like screw holes etc) I had to put the shafts in a drill and gently sand them down with some very fine wet/dry until they fitted without catching. Bright decorative chrome may work but more chance of it rusting etc later on.

The other alternative is to replace the entire bracket. Solves both problems. However any old bracket is almost certain to have shaft pitting.

I had the same problem when I started on my carbs, the shaft was so badly pitted I had to buy a NOS one from DS. His last one as it turns out and when it arrived from America it was missing parts they'd robbed to sell. DS replaced them all after a little bother. CMS still have one left, price is an eye watering £906.52 plus P&P. After customs best part of £1000. Ds price £1002.29 plus P&P. Just spotted this.
https://www.ebay.com/itm/314117753958 doesn't post to the UK though. Might be an alternative solution though.
As it turns out I'll not be using the bracket as I'll be building one up with a hard chrome shaft. Not sure if I want to sell the NOS one TBH, might do if the offer is right.

You think yours was bad, look at my old one.

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Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #17 on: September 18, 2023, 05:30:42 PM »
The bearing is as it came apart Ken - shaft pulled out by hand all done inside a large plastic  box I use for such dismantling - no debris aside from the drilled out retaining rivet when I removed the shaft.

I cleaned the corroded section and pulled it out away from the pinned clamp.

Looking at the inside of the bracket there is a large cut out section where the pin fits imho it was re-built with a half bearing by either Gerben or a previous owner as the remaining area aside from the pin rebate is not jagged.
Only way I can see to save my bracket is to have a brass bearing made with some reaming - expensive. Once the shaft is in place it could be painted & used. They are pretty much hidden away so not a Biggie.

« Last Edit: September 18, 2023, 05:59:56 PM by McCabe-Thiele (Ted) »
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Oddjob

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #18 on: September 18, 2023, 06:04:29 PM »
Sorry Ted, I forgot Gerben had already done this. So it's clear he did remove the shaft at some point, possibly he was a little hamfisted and broke it when he drilled the old rivet out. Which seems to be the case as the break is right where the rivet goes and the hole looks bigger than it should be.

I'd just replace that bracket Ted. If Bryan hasn't got one I may be able to sell you one of my ceramic coated ones, or I have one right now from a set of 550 carbs, same bracket, that I've just pulled apart. Just the bracket, no rod etc.
Kids in a the back seat cause accidents.
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Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #19 on: September 18, 2023, 08:07:01 PM »
Its a shame no one is selling the brass bushes for the throttle shafts.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Online K2-K6

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #20 on: September 18, 2023, 08:43:56 PM »
Its possible there's something available Ted.

Unsure of sizing but an example here  https://www.bearings-online.co.uk/item/3076/PlainOiliteBush/AMC121608-Plain-Oilite-Bush-12x16x08.html that may turn up something that could fit or be machined simply to correct a dimension and give alternative supply.

Online K2-K6

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #21 on: September 18, 2023, 08:47:35 PM »
For the shaft, worthwhile putting a question to the small suppliers of stainless bolts etc that specialise in some old Honda parts as to making replacement in that material.

I'd only consider it's not stainless originally for cost reasons. It'd be completely within material spec for this application in making another now.

Offline Laverda Dave

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #22 on: September 18, 2023, 09:36:06 PM »
I think I would be contacting the guy in the US and would be asking if he would ship to the UK (and send it as a gift to avoid tax!).
Ted, I have used these guys a few times for both welding/fabrication work and also for turning up special parts. I know they are a long way from you but you could give them a call. You need to speak with Kerry as he does the lathe and milling work. They are both great guys, both are past retirement but both love what they do and are good at it. Kerry is also a biker and likes old school jap bikes. https://g.co/kgs/9rSjLy
« Last Edit: September 18, 2023, 09:37:44 PM by Laverda Dave »
1976 Honda 400/4
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1955 750 Dresda Triton
1978 Moto Morini 350 Sport
1978 Honda CB400/4 'Rat' bike
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Offline McCabe-Thiele (Ted)

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Honda CB500 K1 (new pit dug out ready)
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Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline Oddjob

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #24 on: September 19, 2023, 03:43:15 AM »
Offer me half that amount and you can have mine
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Online Bryanj

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #25 on: September 19, 2023, 05:29:10 AM »
And Ken will probably fit the idle scre and spring foc!

Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #26 on: September 19, 2023, 04:29:50 PM »
Sorted the quadrant rivets - an extra large one as well in the spare hole.


.PXL_20230919_151939118 by Macabe Thiele, on Flickr
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #27 on: September 21, 2023, 10:24:45 AM »
I have cleaned up number 1 carb and started to assemble the Emulsion & main jet when I realised how "loose" the main jet was in the carb body - I was able to pull it out by hand when dismantling - now it is barely held in place - not good.

When I fitted new seals in my 400 (kit from NJ) they were a nice firm fit in the body needing a smear of red rubber grease to be pushed in with my thumb - these just do not seal as they should - in fact they start to drop down when turned the right way up!

I'm going to need to replace all the O rings when NJ is back from that Greek island.
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

Offline florence

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #28 on: September 21, 2023, 12:21:05 PM »
can you not get a second hand shaft?

I might be able to find one in my collection.

yes, and bracket

« Last Edit: September 21, 2023, 12:37:03 PM by florence »

Offline McCabe-Thiele (Ted)

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Re: I suspect Ken is right about the quality of Gerben work look at my 500 carbs!
« Reply #29 on: September 21, 2023, 01:55:19 PM »
Thanks for the offer Florence I have secured a bracket from Ken (Oddjob) the shaft is useable now the rust has been removed. I have cleaned it with Evaporust then passivated it. If needs be I can paint in once in place as well.

There is a potential souce of a new shaft in SS from the US in the future. Thanks Ted
Honda CB500 K1 (new pit dug out ready)
Honda CB400 four super sport (first money pit)
Link to my full restoration http://www.sohc.co.uk/index.php/topic,23291.0.html

 

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