Morning All,

I have a brand new 276 carb on my 1947 M20 and had the first start this weekend The one thing that was disappointing was a leaky carb.

It's not flowing out but slowly dripping from the overflow hole on the carb body. It doesn't appear to drip when it's running and is definitely better when the bike's upright.

I've searched previous threads on this forum and it points to one of a few possible issues.

1) Leaky needle in the float chamber - I've cleaned it out and I did find some tiny particles of brass swarf. Maybe the seat has a tiny imperfection?
2) Incorrect nut installed under the main jet leading to wrong fuel level (JO'B has kindly offered to measure his so I can check this).
3) Float level incorrect - As there are only two positions for this (lower groove for plastic float, upper groove for copper float), I'm doubting that it's wrong.

I read a thread about incorrect (or varying lengths of)nuts under the main jet (housing?), this was regarding someone having rich running issues with Norton. The same thread also had a photo of fuel level check using a clear plastic tube.
Does anyone have any data on where the measurement for fuel level should be taken from / to to check it's ok?

Many thanks in advance,

Gino.

email (option): gino_kerekes@yahooooo.co.uk

I would suggest that your bike just needs some miles on it to wear the float needle in properly on the seat. Generally you don't have to play with the float height on the new carburetters such as the 276C/1B. You wont find it written anywhere but the fuel level should be just below the top of the needle jet by a bit over a 1/16 of an inch or a bit more. Trouble is its hard to see this whilst on the bike but easy if in a vice with the top and slide removed and a baked bean can of petrol rigged up to the float chamber. As its metal to metal for the float needle and seat it can weep that bit when the motor is not going but will be fine with the motor going or after a little bit of use. The nut under the carburetter body should be the short one which means when you look at he nut it has the hexagon just below the round threaded part of the nut, if it has about a 1/2 inch shoulder then it is the deep nut and incorrect one. Also do you have the wrong side stand fitted as if its leaning over too far yes the fuel will leak out as the fuel will come over the top of the needle jet.

email (option): ukcarbsathotmail.com

Not totally related but I had some issues with a set of new monoblocs on my 650ss the needle had rubber on the sides where it shouldn't have been and this was causing the needle to jam and covered the bike in fuel the first time I put the fuel on. Swapped the needle and a seat with a spare that I had an that caused the issue then sent a video etc to burlen they are pretty helpful sent me a new needle and seat. I'd pop them a message especially if you found swarf. I ha a set of premiers as well which came incorrectly jetted even though I'd ordered the correct ones. Once they are right though they are brilliant. I was looking at saving up for a new 276 for my Norton be interesting to see how you get on.

Many Thanks,

Tom

email (option): tjsblade@googlemail.com

Thanks for your replies guys,

I'll check the level of fuel and that there is absolutely no debris knocking about (I steam cleaned the tank during the build and fitted a fuel filter).
I don't have a problem with being sympathetic to it, if that's the way it is. I always turn off the fuel on my C15 before coming to a halt and stopping the motor - I'm not sure why really? Maybe adopt a smiliar procedure & see how I go.

Thansk again,

Gino.

PS, here it is, at a point where I had a few small jobs left to do - one of them being moving the horn after it clouted the front mudguard........:face_with_rolling_eyes:

email (option): gino_kerekes@yahooooo.co.uk

While my Amal is not new. I believe it is very old. Anyway it leaked all the time. I lapped the float needle and problem solved.
A very small portion of valve grind paste and a couple of revolutions and back and forth. I got a very small, but very bright ring all the way around the needle.

email (option): cbhaws@verizon.net

I like those rigid tele fork models...I've had a few over the years, M20,21 and M33...After girders the tele forks were a vast improvement and made the rigid bike something that could be hacked about in comfort...Ian...

email (option): ian@wright52.plus.com

A member of the old bike club I'm in has a tele M21. Following her on a run riding my Sportster she was pretty much keeping up to legal limits on give & take roads, something I certainly couldn't do on my girder model.

Thanks for the responses everyone, I'll let you know how it goes!

Gino.

email (option): gino_kerekes@yahooooo.co.uk