Please note that the posts in this blog are in reverse order, so the newest posts are at the top and the oldest posts are at the bottom. You can enlarge most of the photos by clicking on them.

Thursday, May 06, 2010


Someone was telling me that years ago (before spirit levels), they used to get the height and level of the Dado Rails perfect throughout the house by using a hosepipe full of water, so I thought the same principle could be used to see what was going on inside the float-chambers. 

So I connected some clear tubes to the floatbowl drain spouts and opened up the drain taps. As you can see from the photos below, both carbs were pretty much the same in terms of float levels. After all, they're fixed floats anyway! So, as suspected, the floats were working fine and were at the correct height. So what was the damned problem?

I removed the plugs and sat there scratching my head for a while. Then I noticed that the right-hand fuel level had risen dramatically and was flooding the right bore. I switched off the fuel tap and spun the engine using the started motor to eject the petrol through the spark plug holes. And believe me, there was a lot in there! The engine was acting as a fuel pump!  And to add insult to injury, the petrol would have contaminated the engine oil, so another oil-change is due. Grrrrrr!

So, it looks like the carbs have to come off again!! I'm gonna order a couple of new floats and valves from David Silver.

1 comment:

Anonymous said...

I was having the same problem with carb flooding and tried everything to cure it ,I found an idea from utube, what you do is fit a cotton bud into your drill apply metal polish and run this into the needle channel . It polishes the bore so that the needle won't stick . It worked for me, no more flooding

Bike Details

Honda CB250N Superdream
Reg No : ORH746W (ORH 746 W)
Reg Date : 1980
Orig Colour : Blue
New Colour : Black
Current Owner : Tom McQuiggan
Current Location : Horwich, Bolton, UK.