Carb o rings

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Mark
Posts: 145
Joined: 28 Jul 2012 15:57
Location: Cannes, France.
Location: Cannes, France.

Carb o rings

Post by Mark »

Hi.
350K.
Unscrewing the pilot screw and the throttle stop screw on both carbs I see no o rings at all.
I believe they’re supposed to be there although not sure exactly where.
It seems a bit unlikely that all four would have accidentally been lost.
Do they dissolve in time?
Can anyone shed some light please?
Thanks.
3potjohn
Posts: 1243
Joined: 02 Jun 2007 13:58
Location: Devon

Re: Carb o rings

Post by 3potjohn »

They should be there. The mixture screw one may be inside the carb so double check with a torch.A squirt of carb cleaner would not go amiss.
All obtainable from Eurocarb. Actually I did not have any on the mixture screws in my K1 for years ( a senior moment) and it made no difference.The idle responded to the position of the screws as it should.
John
Mark
Posts: 145
Joined: 28 Jul 2012 15:57
Location: Cannes, France.
Location: Cannes, France.

Re: Carb o rings

Post by Mark »

Ok John, thanks for the reply.
Off to Eurocarb site, may as well get a couple of 43/44 pilot jets as well as that seems to be the received wisdom.
Cheers.
EVguru
Posts: 1528
Joined: 01 Aug 2006 11:13
Location: Luton
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Re: Carb o rings

Post by EVguru »

I have seen many, many carbs with no O-rings fitted. In fact I'd say most that haven't been rebuilt have had no O-rings.
Paul Compton
http://www.morini-mania.co.uk
http://www.youtube.com/user/EVguru
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Carb o rings

Post by mbmm350s »

EVguru wrote: 17 May 2021 21:19 I have seen many, many carbs with no O-rings fitted. In fact I'd say most that haven't been rebuilt have had no O-rings.
I agree with Paul, I have seen many without o rings.
An English translation of A Dell Orto document I have by Contact Developments of Reading (precursor to Eurocarb) from the
1970s shows no o rings. Critically this applies to the VHB BS carburettors so pre dates 1976/7 and the introduction of VHBZ BS carburettors
I would expect by the VHBZ HS carburettors (1979) for these O rings to be present as they are shown in the drawings. Evolution of these carburettors
likely for emissions reasons as extra washers/rings etc would add extra manufacturing costs.
Whether fitted or not unlikely to make any difference as John says. What is worth checking is that there isn't a stack of lost and forgotten
washers and o-rings hiding at the bottom of the mixture screw hole.
Cheers
Mark
Mark
Posts: 145
Joined: 28 Jul 2012 15:57
Location: Cannes, France.
Location: Cannes, France.

Re: Carb o rings

Post by Mark »

Yes, on subsequent investigation I too found old diagrams showing no o rings.
I shall indeed poke around to be sure none are there but it seems that none were ever fitted.
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