Checking Monobloc float level

Step into your time machine and travel back to the 70's. Pick up a float bowl extension, and add the perspex cover. I've got one on my Tiger Cub back there.......

Admittedly it has twin monoblocks, but I undo the carb - carb connector pipe between the main jet and reposition it up the side of the float chamber to record fuel height. 

Just like using non J9 grade fuel hose, you have to be careful with plastics and modern fuel to make sure it doesn't break up/dissolve when they are in contact with each other.  I wonder how I know this...

Regards, George 

I thought that you could undo the pilot jet and push a pipe on there. Or isn't that for Monoblocs? Worth a look.

Think that I was nearly correct! By sheer coincidence I have just seen a comment on the Velocette OC website saying remove the pilot jet cap and push a pipe on there.

This is what I made many years ago and it works perfectly.  I used a spare pilot jet cover and drilled a small hole in it, I then soldered a small piece of brass tubing into it and connected some clear plastic pipe to that.  It's a tool for life :)

It is just possible to push a bit of clear pipe onto the pilot jet, it will drip as fuel runs past the thread  and its a bit hit miss but it can work. A perspex cover may work if you are quick but is likely to disolve fast. Fuel level also seems to vary  a tad with the head of fuel , go with half a tank.

I took an oversize scrap of perspex, drilled three holes in it and put it on in place of the metal cover.  Oversize so the holes didn't break out of the rather brittle material. Make sure the plastic is petrol proof...polystyrene might turn into glue...it wasn't even cut to any special shape.

Hi David ,  The perspex  cover you kindly made for me did the job but  was disolved by my tank contents in no time ! , perhaps Esso synergy plus  has an "ESSO EXTRA bleedooler" component  thats not kind to plastics , or  the  station  was passing off cheap E10 as  the plus grade . Its been done to me before.

I can send you an extension with sight glass. To set up your float.  But I will want it back…  I still have monoblocks on my plunger dommi.  Email me 

cheers

Jon

The idea of pushing a plastic pipe over the pilot jet - once the cover has been removed - doesn't work very well, as it not only drips fuel, but also allows thousands of tiny air bubbles to enter the pipe and therefore doesn't give a very accurate reading.  I know, because I've tried it many times before and the pipe really must be sealed where it joins the jet and that's why I made an adaptor.

That's all very well, but with the nylon float, how do you adjust the level if its wrong? If I remember correctly (but possibly not) with the old copper floats, you could lightly (!) bend the arm, but can you do this with the nylon float?

Michael, I went back to using the old type brass float for that very reason.  With the plastic float you can raise the level with washers under the float needle union/fitting, but I don't think you can lower it unless you machine a fraction off the top of the carb or from the underneath of the float needle seating union.

I have chased richness on pilot settings for some time including having the float needle seating machined. drilling extra air bleeds and increasing bypass sizes. Eventually I concluded that once the engine reached full temperature and the pilot mixture was correctly adjusted then the apparent richness (displayed on reading the plug) would very slowly clear up. I atribute this condition to the poor self cleaning ability of some current spark plugs that absorb carbon into the insulator. Ancient plugs seem to fare better.

I think that the screw in the side of the body engages with the jet block  ,so maybe if the block was the wrong way round it would not go in? .