Sachs 6B Carb Size, Jetting, Troubleshooting

[Ernie Phillips]

The Bike:  1973 125 6-day, new to me, and believed to be modified.

The carb on the bike is Bing 84 marked 1/30/108  (148 main, 45 pilot)

The problem is that the bike will run just fine on the idle circuit but will not "take the throttle"  I can tickle it and get it to go.  After awhile of riding and tickling the bike runs OK.  I cleaned the carb several times.  You have to tickle it to get it to go.  What am I overlooking?

Additional info:  The bike came with some spare parts and I found another carb - Bing 84, marked 2/30/102 (140main, 40 pilot).  With this carb, the bike starts and runs fine, though is lean on mid range (needle setting?)and maybe on top but unable to run-out in my subdivision.

What is the stock carb for this bike?  jetting? good starting point?

Ernie P.
Chattanooga, TN

[Doug Wilford]

Ernie, this may sound dumb but it can happen.  The atomizer may be in backwards.   The top of the atomizer has a half moon ring. The solid part of the moon half should be faceing the air cleaner.
If not the engine wants to die as soon as you start to turn the throttle.   Jetting 145 Main should work fine.  Have Fun!

[hrbay]

Ernie, pull that pilot(idle)jet again... it soumds like it is full of gunk. If you can hold it up to a bright light source and can't see a hole, well it will cause this problems.

GC

[Ernie Phillips]

Doug & hrbay,

Thanks for the suggestions.  I disassembled the carb and found the atomizer installed correctly and pilot jet was "clean as a whistle."  Something unusual that I did discover was a very fat needle.  I mean, the needle had almost no taper to it - obviously creating a very lean condition when the carb goes from idle to mid-range.  I don't know how the bike was ever rideable this way.  Anyway, it is nice to find the solution.  When you buy a used bike that is 34 years old -- no telling what you'll find.

Ernie P.
Chattanooga, TN