CB250RS carb technical question

[BrendanO]

OK, this is a REAL anorak question...

CB250RS A carb, when the float bowl is off, on the mating face there's a float bowl gasket, but also a wee o-ring for the accelerator pump sprayer thing (looks like a brass square, set in a bored out circle). i's not located at the acelerator pump, but along a bit. I'm missing the o-ring, and think it's been missing a while (!). Having fixed the accelerator pump, it now pisses petrol out from where the o-ring isn't (of course).

What dimensions for the o-ring? it's about 5 mm-ish, but nothing from local helpful Honda dealer's box of o-rings seemed quite right! Trying NOT to buy a whole carb refurb kit (and wishing I'd left well alone!). Hoping to be able to order exact dimension one from some auto parts place (any advice?).

What's the betting this gets an answer tonight?

<frustrated, but laughing>

Brendan

[themoudie]

Aye BrendanO,

Embra 'll be a dreek hole tonight, I bet? I have to drive to the Uni tomorrow morn from Perth! 

Whilst not knowing a toss about the guts of a CB250RS carbie, might I suggest an 'investment' of a couple of Hawick £, at a local Halfrauds in a small cellophane pack selection of 'O' rings of small diameter? Problem wi' these things is you always see them after they're perished and squidged between lumps o' metal for o'er long. The new plump, circular ring looks impossibly sized. The diameter of the ring material as well as it's overall diameter seemingly 'BIG'! 

If you have no joy, ring Dave Silver Spares, Leiston, Suffolk  (home of the Garrett Steam road locomotive works) Link: David Silver Spares and ask what they may have to offer, you maybe pleasantly surprised!

Go canny, Bill.

[jester_parks]

try one o-ring of a o-ring-chain: 428, 520, 530 might give you the required (small) size

[crackedhead]

Hi,

Try http://www.nrp-carbs.co.uk/contact_us.htm. They were very helpful when I had a problem with my XBR carb and supplied a kit for about £20 that contained the jets, o-rings and needle.

I'm in West Lothian, so I'll have a look in my XBR spares stash and see if I have any o-rings lying about.

Good luck.

[crackedhead]

or you could buy a selection of o-rings from fleabay, for a few quid. One example:-
http://cgi.ebay.co.uk/MIXED-METRIC-O-RINGS-3mm-50mm-50-Pack-Kit-Car_W0QQitemZ370090370099QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item562b1ae433

[mini-thumper]

Brendan
Just had my spare RSA carb apart and measured the offending article. Measurements are:

O/D = 7mm
I/D = 4mm*
Wall thickness = 1.5mm*

* both these values could be slightly distorted from the o-ring being compressed, for a very long time, against the face of the mating surfaces - but they should hopefully give you a starting point!

The o-ring actually holds the square brass pin in position, creating four very small passages between the outer edges of the pin and the inside edge of the o-ring; the square brass pin does not slide through the o-ring as far as I can see.

Hope this is of some use. Good Luck!!!!

Boyd

[BrendanO]

Excellent! What a great range of useful answers!

Knew this was the place to ask!!

B