Author Topic: Carb inlet manifold rubbers  (Read 1112 times)

Offline rosco

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Carb inlet manifold rubbers
« on: November 27, 2019, 04:27:59 PM »
Just got my inlet rubbers back from Ash who has softened them Now I've come to fit them and noticed there are two different types ( didnt notice when taking them off  DOH ) Two marked 1&4 Two marked 2&3 Obviously to fit each cylinder   Question is are the numbers fitted uppermost on the corresponding cylinder  IE  cylinder No 1   mark 1 to top  mark 4 bottom  cylinder No2 2 to top  3  to bottom  ETC   Ive searched all service manuals and nothing on removing / refitting  Cheers Ross

Offline Nurse Julie

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Re: Carb inlet manifold rubbers
« Reply #1 on: November 27, 2019, 04:32:11 PM »
Yes Ross, 1,2,3,4 uppermost from left to right whilst sitting on the bike.
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Offline rosco

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Re: Carb inlet manifold rubbers
« Reply #2 on: November 27, 2019, 05:18:03 PM »
Thanks  Julie   It seemed logical but not certain due to the shapes being different I have fitted them to the carbs and they look right   Ref your carb screws Yes Gerben has fitted 12mm plus washer to mine   Cheers Ross

Offline Andrew-S

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Re: Carb inlet manifold rubbers
« Reply #3 on: November 27, 2019, 05:45:41 PM »
As Julie says, plus I believe these are rare original fitment as the 'new OE' ones supplied by DS (and others) are un-numbered.
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Offline Erwin83

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Re: Carb inlet manifold rubbers
« Reply #4 on: December 04, 2019, 01:34:20 PM »
On this topic: i recently got a set of (non-OE) replacements for my 400f. These are all 4 the same. They're <35 GPB for a set of 4, so the price is attractive enough.,,

I already pointed out to the (english) ebay seller, that the fitment is not ideal. He responded that he's sold over 200 sets, and they work fine.
My conclusion is: yes they work, but they don't work very well. It takes a lot of force to install the carbs all the way, even though the rubber is nice and soft.

Anyone have experience with this?
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Offline Nurse Julie

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Re: Carb inlet manifold rubbers
« Reply #5 on: December 04, 2019, 01:38:45 PM »
If all 4 are the same, they can't fit properly, as 2 are angled differently than the other 2. I can't see how they will be a good fit if not angled correctly. We are talking about manifold to carb rubbers aren't we, not carb to airbox rubbers which are all the same?
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Offline sprinta

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Re: Carb inlet manifold rubbers
« Reply #6 on: December 04, 2019, 01:43:19 PM »
On this topic: i recently got a set of (non-OE) replacements for my 400f. These are all 4 the same. They're <35 GPB for a set of 4, so the price is attractive enough.,,

I already pointed out to the (english) ebay seller, that the fitment is not ideal. He responded that he's sold over 200 sets, and they work fine.
My conclusion is: yes they work, but they don't work very well. It takes a lot of force to install the carbs all the way, even though the rubber is nice and soft.

Anyone have experience with this?

Try a little silicon grease on the outer lip faces of the carbs and a little on the inner faces of the rubber tubes, I find that helps.

Offline Erwin83

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Re: Carb inlet manifold rubbers
« Reply #7 on: December 04, 2019, 02:04:15 PM »
If all 4 are the same, they can't fit properly, as 2 are angled differently than the other 2. I can't see how they will be a good fit if not angled correctly. We are talking about manifold to carb rubbers aren't we, not carb to airbox rubbers which are all the same?

We're talking about the manifolds indeed, between head and carb.
The offset of the middle two is limited (just 2-3 mm out of center or so), so this set is supposed to be just pushed/forced in the "angle".
With force, they do fit. And at 35 GBP for all 4 boots, I still think it's a good deal.
I'm just wondering if anyone else has this experience.


On this topic: i recently got a set of (non-OE) replacements for my 400f. These are all 4 the same. They're <35 GPB for a set of 4, so the price is attractive enough.,,

I already pointed out to the (english) ebay seller, that the fitment is not ideal. He responded that he's sold over 200 sets, and they work fine.
My conclusion is: yes they work, but they don't work very well. It takes a lot of force to install the carbs all the way, even though the rubber is nice and soft.

Anyone have experience with this?

Try a little silicon grease on the outer lip faces of the carbs and a little on the inner faces of the rubber tubes, I find that helps.

I used WD40, similar?

Problem was that before tightening the clamps, the carbs were pushed out again. Due to the angle.
CB466f - KTM 1190 advR

Offline Nurse Julie

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Re: Carb inlet manifold rubbers
« Reply #8 on: December 04, 2019, 02:13:47 PM »
If all 4 are the same, they can't fit properly, as 2 are angled differently than the other 2. I can't see how they will be a good fit if not angled correctly. We are talking about manifold to carb rubbers aren't we, not carb to airbox rubbers which are all the same?

We're talking about the manifolds indeed, between head and carb.
The offset of the middle two is limited (just 2-3 mm out of center or so), so this set is supposed to be just pushed/forced in the "angle".
With force, they do fit. And at 35 GBP for all 4 boots, I still think it's a good deal.
I'm just wondering if anyone else has this experience.


On this topic: i recently got a set of (non-OE) replacements for my 400f. These are all 4 the same. They're <35 GPB for a set of 4, so the price is attractive enough.,,

I already pointed out to the (english) ebay seller, that the fitment is not ideal. He responded that he's sold over 200 sets, and they work fine.
My conclusion is: yes they work, but they don't work very well. It takes a lot of force to install the carbs all the way, even though the rubber is nice and soft.

Anyone have experience with this?

Try a little silicon grease on the outer lip faces of the carbs and a little on the inner faces of the rubber tubes, I find that helps.

I used WD40, similar?

Problem was that before tightening the clamps, the carbs were pushed out again. Due to the angle.
Mr Honda didn't give them 2 different angles for no reason. When I put my manifold rubbers on after the engine rebuild, I got those 4 rubbers on incorrectly, as at the time I did not understand the significance of the numbers on them. Fitted incorrectly, they definitely pushed the bank of carbs out of alignment. I didn't have any air leaks but, you could definitely see opposing forces were at work. As soon as I took the manifold rubbers off and got them in the correct order, everything fitted like a glove and was perfect. I use a smear of red rubber grease on all the carb boots / manifold boots etc when fitting, never WD40.
LINK TO MY EBAY PAGE. As many of you know already, I give 10% discount and do post at cost to forum members if you PM me direct.
https://www.ebay.co.uk/sch/julies9731/m.html?item=165142672569&rt=nc&_trksid=p2047675.m3561.l2562

LINK TO MY CB400/4 ENGINE STRIP / ASSESSMENT AND REBUILD...NOW COMPLETE
http://www.sohc.co.uk/index.php/topic,14049.msg112691/topicseen.html#new

 

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