running rich

[sclafani]

1965 R50/2. ….one of my cylinders is running really rich…..anybody have any suggestions?

[schrader7032]

Original brass floats? If so, they can crack and intake gas, which causes them to sink. Easy enough to check.

[sclafani]

floats are new

[schrader7032]

New-in-the-box brass floats can crack. Vech had plastic floats produced which were a good replacement...at least version 2.0 has been stable. Again, easy enough to pull the top of the float chamber off, pull out the float and shake it to see if there was gas in it.

Sometimes the rod that runs through the float can stick in the holder at the bottom of the bowl. Corrosion in the pot metal builds up and grabs the rod.

[Slash2]

I got about 2 years out of a set of Vech’s plastic floats. At the end of this season I noticed a change in the tone of my engine as I headed home from a short ride. I pulled apart my carb to discover my right side float was half filled with fuel.

I guess I’ll go back to brass but for the price I hope I can find one that isn’t already cracked.

[sclafani]

floats are new/good ….I did check for leaks

[skyler.robbins]

When was the last time you did a carb sync? I take it all if your carb settings are correct? Have you cleaned the plugs and swapped sides?

[Micha]

Is it possible to solder that crack?

[vechorik1373]

Here are some questions for you.
What type of float chamber lids do you have? In case you do not know, there are two versions.
The lever tops have the fuel line nipple entering the lid off center.
The old style have the fuel line enter in the dead center.

What to check on the old style:
The end of the brass nipple that hose pushes onto IS the seat for the float needle. The brass nipple is pressed into the lid and set at particular depth through the lid. If the uninformed owner, has been pulling the fuel line off, by using pliers, the chances are pretty good that the nipple has been pulled up out of the lid. If the fuel line won't come off, using your bare hand, STOP! Never attempt to pull the stuck fuel line off with pliers. Use a single edge razor blade and split the fuel line and then remove it. High float level = running rich. To figure this out, remove both lids, and measure to see how much nipple is sticking through the lid on the side that is flooding/running rich, versus how much is sticking through the lid on the side that is running correctly. If you find that the nipple has moved up on one side, lay the lid over the open jaws of a vise, and using a light hammer, tap the nipple back down in the lid, measuring each time after a hammer blow.

How to check a lever top lid:
Remove it from the carb, turn it upside down, and measure from the gasket surface to the bottom surface of the lever.
the bottom of the lever should be 22 mm above the gasket surface. You can make yourself a quick gauge out of poster board paper, or a more permanent one out of brass. The photo is of the one I made, since I worked on these bikes for many, many years.
If your lever is too high, or low, you must bend it to adjust it.

And one other thing that I had happen to me while riding, was I lost one cylinder completely at speed. When I stopped and pulled the plug on the dead side, it was JET BLACK and sooted up. It turned out that the main jet, had unscrewed itself from the needle jet, and had fallen out, and was laying in the bottom of the external cap that covers the main jet! Talk about going rich instantly!
I put it back in, and suddenly, it ran perfectly again!

[vechorik1373]

The floats for the twins weigh 7 grams. If your brass float is cracked, in an emergency, you can attempt to solder the crack just to get you home, but you must replace the float, because "repairing" the float will add to it's weight, and cause the float level to rise.