Saturday, February 15, 2014

Drained The Tank

On Friday morning, the bike had water in the carb bowls again. Since my Mr. Funnel water trap came in a couple of days ago I pulled the tank and completely drained the tank through the filter. There was a little over a gallon of gas left in the tank and this is the water that was collected in the sump of the filter. An almost insignificant amount amounting to maybe a tablespoon. More water than this came out of the left carb bowl. I now believe that water is getting into the carb bowls through some other route.

Time to dig out the carb manual and see if there is a route where moisture from the air passage could possibly get into the bowl. The only path should be through the main and enrichener jets.

6 comments:

Erik R said...

Interesting. I hope you get it figured out soon.

Conchscooter said...

I learned some stuff about your bike last night. I thought the old RS and RT series were perfect!
I can't paste the link but check real classics uk magazine website.

RichardM said...

Interesting magazine. I read the article and it makes me wonder about the author. The battery comes out easily without the removal of any other parts. Maybe whomever installed his sidecar installed an extra brace that went over the battery. Not required with a well designed subframe but absolutely essential if a subframe isn't used. It is well known that bleeding air out of the rear brake can only be done with the caliper removed due to the shape of the hard brake line. This is only if the line is removed or replaced. As far as effectiveness, it is almost too easy to lock up the rear wheel with the rear disc and a light touch is needed. The rear drum is supposed to be more forgiving. The weight transfer to the front only makes it more difficult. They changed to different front disc brakes the following year which were more effective. Still a far cry from more modern brakes. What he describes with the carbs is exactly what I'm seeing when I get water in the bowls. The main circuit is only sucking water but the enrichener circuit uses a different fuel pickup. And even riding in triple digit temperatures in the western US, I never experienced any vapor lock. Maybe the load of the sidecar or lugging the engine would increase the temperature sufficiently. But if fuel evaporation due to heat is the reason then the enricheners wouldn't work either as they draw from the same bowls.

Sorry for the long answer...

RichardM said...

I like problems like this...

redlegsrides said...

Well, if I recall correctly, there's a vent on the carbs....make sure they're oriented correctly? So, if no significant water in the tank, interesting.

Am assuming your seals on the bowls are good to go?

dom

RichardM said...

The bowl vent is a tiny tube pressed into the bottom of the bowl and extends to a point well above the fuel level. I just pulled the bowls and, surprise, there was a little water in both bowls. The vents are both secure and open to the atmosphere. Maybe if there is snow on the carb bails, when it melts and runs down the bails it may be drawn in the vent by capilary action. The bail runs right under the vent.

I could try the newer Bing design with dual floats. Due to the larger size of the floats they eliminated the vent tube.

Both bowl gaskets are in place and in good condition.