I just changed from a Mikuni back to a stock 27mm Bing on a 6b Sachs. I have to run the idle mixture screw all the way in to get the motor to take the throttle. The pilot jet is a 40. Anyone having to run bigger with this motor? The main jet is 140 and runs great on the top end.
How old is the pilot jet and slide? Most of the lower Rs trouble I have seen with Bing carbs over the years is from the needle jet being worn or the slide being worn or both. Check this and replace and I bet it fixes the prob. Hard to tell with the needle jet but not too expensive. The slide will have a smiley face if it is too worn. I don't remember having to use bigger than a 40 pilot jet in fact mostly 35.
Larry P
See page 4
http://pentonusa.org/publications/keepingtrack/No.%204%20March%201973.pdf
Steve Minor
Raise the needle one notch...or bring the Honda!
Richard Colahan
1969 V1225
Upper Black Eddy PA
We had some discussion last night on the status of the choke. The cable hole is filled with sealer. My suggestion was to check to see if the spring, plunger, and seal (which if gone or deteriorated) may not be sealing off the choke circuit properly.
Dale Fisher
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Took the Bing back off and rechecked. Drilled out the pilot to 45 and now I have adjustment. Will ride the Rocket in the morning and see how it goes. Been riding a four stroke Honda the last few years so getting back on a 2stroke will be fun. I will be sucking wind at the back of the pack after not being on a dirt bike for nine months. Any other Pentons making the race?
Anyone else know what their jetting is for a bing on a 125b motor.
Rick
Is a 270 jet with a #4 needle richer or leaner than a 273 with #5 needle?
Rick
LEANER. Did you ever check the slide condition?
Larry P
Larry
The slide is in good shape. Tried the 270 with #4 needle both up and down. Then went back to 273 with #5 needle, 45 idle and 140 main, with the needle raised all the way up. 100LL avgas 32/1 Yamalube. Pouring rain here but a few laps around the yard seems good. This motor wants lots of fuel. Race is on Sunday, we will give it another go. Will do the sighting lap, if all is well I will leave the Honda on the trailer.
Rick
Best of Luck in your race Rick!
Larry P