Monoblock Fuel Level for 650

I have played with new plastic floats and had the same issue,eventually I went back to the old brass floats . the plastic floats were jamming on the alloy casting and not closing. The old brass floats had wear at the needle contact  and I countered this by turning  10 thou off the needle valve body.where it meets the carb body.

... and as far as I know it corresponds to the centre of the needle jet so that rotation shouldn't affect that. It would of course place the pilot jet lower but I think that's submerged anyway.

hello well for amal twin carbs you need one and a half turns on the air screw or thereabouts and drop the main jet size to a 240 from 250 main jets and you need to check the needle valve body the one were the fuel comes in as a banjo fitting for the fuel pipe  some fit a wash on the underside of this body just need to unscrew it and find out  the level  on the float  from there  and try a vitiron tipped needle valve,  My Manxman 650 is on a single carb  as we have more slower A and B road around here and Twin Carbs just use more fuel  And at my age I have slowed down, and do have a look on youtube for Amal monobloc problems  ,yours  anna j

Hi George,  I totally agree, if its working ,leave well alone and get riding. The plastic floats have casting flash which needs to be removed  and they seem able to jam on the castings in the lower part of the chamber if the fuel level drops. I put in a stop to restrict the float drop but then also had to file off a bit from the cover (similar effect to your extra gasket). Now I just have to work out why my tickler won't work since I put back the brass float. I am also going to solder up the needle valve air bleeds and re-drill them smaller to counter a weak spot at the bypass phase,after trying all the usual fixes.  A Norton is good for exercising the brain.

hello in order  to reduce the float blow leave  you to need to change out the needle valve holder that lets in the fuel  or and  you can file off some of the alloy were it is mounted by shaving off a few thou make a big difference in the float blow leaves has the fuel comes in then the valve shuts off earlier  so then you do not get flooding  in the carburettor it's that easy     yours  anna j        

Anna is  proposing that to reduce richness found in some monoblocks you can machine off 10-20 thou from the float needle valve body where it abbuts the carb body.. This could compensate for wear on the  brass float  where years of use against the needle bottom forms a hollow in the brass. .In theory you could also file off the carb body where the valve body seats ,I can't imagine doing that easily or accurately .I have a machined off valve body as a spare but not found it to be helpful up to now. You can also put a shim or fibre washer under the valve to raise the fuel level .One would hope that just replacing old parts with new would solve all the issues.,  If only!.

... a plastic float on a monobloc that had a casting flash that would occasionally catch on the float chamber and stop it from rising enough to shut the fuel flow off.

Hello I did say file off the alloy base where the float valve fits and you can get many types of of files for this type of job I have over 100 of them, and you can try lowing the throttle valve needle a knotch or two Or changing the main jet to a smaller one jet, yours Anna j

hello  now what if the float is not sticking  and you still have the same problem of flooding of the carburettor  so the only way you can rectify this is as I have said file  down were the needle valve holder fits so you get a right leave of fuel  I have done this with my carb witch cured this problem  George   and it was nothing to do with sticking floats  witch we check beforehand  I know Amal carburettors backwards by now  of owning Norton for well over 55 years  My name my be Anna But I do happen to have personnel experience with Nortons and Other Motorcycles  Modern and Vintage Along with Diesels  Vans And Cars  And fuel injection  systems  mechanical and electronic   yours  anna j   

Anna, most everyone knows how much experience you have with Norton's, but there is more than one way to cook an egg! People have different methods and ways of doing things for different reasons, we all don't have the same heads or experiences.

Please, try and take things less personally and  be more objective, round the issues, I am not having a go, but trying to save you from self-inflicted personal grief. 

From your mate.

Mick Walker says the 600 cc Normad of 1958 had left and right handed Amal carbs! Hen's teeth no less! Did you know some birds do have quite pronounced teeth ridges? Usually aquatic species!

John

Hello John well pre mono bloc are now been made new and amal pre mono bloc come in two flange fitting the snub fitting or two 5/16s stud fitting and they do all the jets and needles and new stay up floats even I managed to get the twin carb set up for my 1954 Dominator model 88 witch some where fitted as a clubman model but you did have pay that bit extra for off the shelf go fester bits from Norton or a Norton dealer ship there was. A separate part book that one time most of these will be lost in time   yours. Anna j

Hi George, When I had the same problem I compared the old and new gaskets (thinking that the new one was too thin)  ,could not see any difference, then I put a straight edge accross the chamber at the spacer point and realised the spacer was being pushed against the cover by the float, a little bit of filing gave a thou or two more clearance. Similar effect to 2 gaskets.Still does not explain why using an old brass float raised the issue!,Maybe the wear pit at the needle contact is trapping the needle a fraction. Having an old Norton keeps the brain fully occupied. Whats this I hear about a Virus going round??!.