Honda-SOHC
SOHC.co.uk Forums => CB350/400 => Topic started by: Mikep328 on September 28, 2023, 10:12:43 PM
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Those rubber parts on my 400 are quite hard, more like plastic than rubber. Is that normal? The airbox is a DS replacement from 2018, I don't know about the age of the manifold/carb rubbers. The clamps, which appear to be original, have to be closed to the maximum to apply decent pressure and even then the airbox rubbers can slide on the carbs if pushed/pulled in/out.
I see that the manifold to carb rubbers are available at DS but I don't see the airbox/carb rubbers available. Is there a source for them other than DS?
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I've just finished getting a set of them. They weren't on their website so I phoned in about them and they had them, maybe they are slow updating their site. I think they described them as 'carb to manifold rubbers' though. Note they supply the airbox manifold complete with rubbers, maybe they pinched mine of one of those? ;) The most forward ones are the cylinder head to carb rubbers and seen on their site just now. The manifold to carb are the rear set, note that the airbox has that manifold in between itself and the rubbers!
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Are the new ones supple/rubbery as opposed to hard, plastic-like?
Related to carburation...I've also been kicking around the thought of velocity stacks though I have read all the posts re the difficulty (impossibility?) of getting the fueling correct to run well with them. If I decided to try a set, what size/where can they be obtained?
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Not certain on the 400 ,but the airbox to carb rubber are velocity stacks,
Lovely opening shape,
The outer ones are handed,
With a proper way to fit them
Sent from my SM-A546E using Tapatalk
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Not certain on the 400 ,but the airbox to carb rubber are velocity stacks,
Lovely opening shape,
The outer ones are handed,
With a proper way to fit them
Sent from my SM-A546E using Tapatalk
Meant to say on the 500
Sent from my SM-A546E using Tapatalk
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I bought a set from DS at the beginning of the year. They are relatively soft and make fitting the airbox to the carbs a doddle compared ot the hardened ones that they end up to be. Can't find the receipt for the ones I bought....
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After softening inlet rubber for loads of other people over the years I actually did some for my own 400F a couple of weeks back ... .. They turned out really good after being quite hard initially.
Problem is I can't get the chemical any more as my industrial source has stopped trading.
This was the stuff https://lanxess.com/en/Products-and-Brands/Products/r/REOFOS--50
This was the original 750K7 one I did about 10 years back
https://www.youtube.com/shorts/Y1kVSlLnR8k
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Ooh, Ash, tell us more!!
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Ooh, Ash, tell us more!!
Told lots of times on here about 16 hours immersion at 70°C in bath of Reofos 50 as in links above.
As I said though the place I got it from bought it in massive drums for rubber/plastic processing and I used to cadge a litre or so off them but they their factory in Hull closed earlier this year. I have enough 'in-stock' to do my own bikes but sadly I can't do other members any more.
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Checked with DS today and they are out of stock of the airbox to manifold rubbers. They suggested to check back in a month. Again, mine are not all that bad - they are somewhat supple though, as I said, the clamps have to be fully tightened to their limit and you can still slide the airbox back/forth on the carbs. The manifold rubbers look/feel/sound like plastic! DS has those in stock - genuine or aftermarket.
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Ash, I know bugger all about chemistry but is this guy making his own type of Refos 50?
https://www.youtube.com/watch?v=9eTF6tnYYdc&t=344s&ab_channel=IchibanMoto (https://www.youtube.com/watch?v=9eTF6tnYYdc&t=344s&ab_channel=IchibanMoto)
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I'm sure someone here uses Wintergreen Oil?
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Ash, I know bugger all about chemistry but is this guy making his own type of Refos 50?
https://www.youtube.com/watch?v=9eTF6tnYYdc&t=344s&ab_channel=IchibanMoto (https://www.youtube.com/watch?v=9eTF6tnYYdc&t=344s&ab_channel=IchibanMoto)
Sent you a pm Matt ;)
Isn't Ichiban channel a kind of spoof where he suggests zany methods that sound feasible but are really a load of b*llocks
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I'm sure someone here uses Wintergreen Oil?
Yes lots of people use it but I went for the stuff used industrially by the rubber processing industry.
A few guys on here I have treated parts for can report their findings if they want to chip in.
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Isopropyl alcohol and wintergreen….it’s a temporary fix, but works. I’d have used Refos 50, but it seems to be unobtainable locally.
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In past projects I tried wintergreen oil and several other liquids/combinations that can allegedly soften old rubber. I found that while wintergreen worked initially, a week (or less) later the rubber was a hard as it was prior to treatment. So my experience - admittedly with "commonly available" items - was that "restoring" rubber parts made them flexible enough to be re-attached/re-mounted but they returned rather quickly to their hardened state.
On the good side, if you don't plan to regularly remover/re-attach the particular rubber part, temporary softening might be all you need.
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In past projects I tried wintergreen oil and several other liquids/combinations that can allegedly soften old rubber. I found that while wintergreen worked initially, a week (or less) later the rubber was a hard as it was prior to treatment. So my experience - admittedly with "commonly available" items - was that "restoring" rubber parts made them flexible enough to be re-attached/re-mounted but they returned rather quickly to their hardened state.
On the good side, if you don't plan to regularly remover/re-attach the particular rubber part, temporary softening might be all you need.
Parts I have softened with Reofos 50 over ten years ago are still as soft as when I forst treated them BUT that's not on a bike being exposed to fuel.