1972 dual cable solex carbs let side sputtering

[BRok13]

I can get an idle on my solex carbs although when I take the filters off and raise the right carb throttle by hand the diaphram lifts as normal and the rpms go up .. When I do the same to the left (main with carb choke)carb the diaphram does not lift and makes a sputtering noise like it's not getting any fuel.. these were running fine earlier in the day other than jetting adjustments that would need to be done. Once I really got down on it this is when the problem occured.. Could this be a clogged jet maybe from something in the fuel ?

 

[Rat650]

Hey Brok, I have the same carbs on my 72, they have been finicky for me in the past as well. What I did was give them a really good cleaning and replaced the fuel filters and made sure the floats were adjusted correctly. Are you getting good spark on that side? Also it's really strange but mine runs rough if I let it go below half a tank.. Don't have a clue why but as long as I keep her topped off it's been smooth sailing, let it go a little below half and she gets sputtery and moody. Good luck man!

 

[XSLeo]

I agree with Rat650 your carb could need cleaning. Have you read www.amckayltd.com/carbguide.pdf ?
On running poorly below 1/2 tank it's your fuel fdilter. Some have to much resistance to flow with a gravity fed system, as most bikes are. Some filters are for systems with fuel pumps and the extra restriction isn't a problem.
One way to test is to unhook the fuel line from the filter to the carbs, attach a longer hose. Run the hose to a gas can. Turn on the fuel, watch it as it runs into the gascan, once the level gets below 1/2 tank does the flow slow? If so the filter is the problem.
Another way is to run with out the filter to see if it runs poor below 1/2 tank.
Leo

 

[Rat650]

I agree with Rat650 your carb could need cleaning. Have you read www.amckayltd.com/carbguide.pdf ?
On running poorly below 1/2 tank it's your fuel fdilter. Some have to much resistance to flow with a gravity fed system, as most bikes are. Some filters are for systems with fuel pumps and the extra restriction isn't a problem.
One way to test is to unhook the fuel line from the filter to the carbs, attach a longer hose. Run the hose to a gas can. Turn on the fuel, watch it as it runs into the gascan, once the level gets below 1/2 tank does the flow slow? If so the filter is the problem.
Another way is to run with out the filter to see if it runs poor below 1/2 tank.
Leo

Interesting, I never thought of the filters being the problem but it makes sense. I'm going to have to try this. Brok let us know if any of this works for ya. Thanks XSLeo!

 

[BRok13]

well I checked my jets and passage way's everything was clear , I realized after rebuilding these carbs and trying to tune them I fouled out my left plug which was the reason it wasn't firing , replaced the plug good to go ... although now I get hesitation mid range .. Im running stock 130 main and 42.5 pilot . I just got in a 132.5 main and a 45 pilot gonna try that to see if it clears things up.

 

[TwoManyXS1Bs]

Did you do the diaphram test, found in: http://www.amckayltd.com/carbguide.pdf
Especially on the left side?

 

[BRok13]

diaphragms are good , once I replaced that plug everything was fine now Im just working on fine tuning them and getting rid of this hesitation

 

[TwoManyXS1Bs]

In post #1, you said the left diaphram wasn't lifting the slide. Does it work now???

 

[BRok13]

yes it's working now , what was happening was with that plug being fouled it wasn't firing when I lifted the throttle , I mis-diagnosed the diaphragm part.