Having trouble wit my 1974 Penton 6-days trying to get the bike to idle and just cant seem to get the air mixture screw adjusted - maybe doing something wrong.
I gently seat the screw and then back it out half a turn and go from there. when using the throttle the keep the bike running, it seems to be bogging and then dies. any thoughts to this condition - ? any suggestions as to how many turns out from seated the mixture screw should be at least initially ??
If you have a factory manual, consult that, but I think it says to be out at least 1 1/2 turns. all the way in, and then out 1/3 turn will make for a rich setting. The engine needs to be warm and at operating temperature. Make a small adjustment and then ride it around a bit and then see how it idles. Where your idle is set at will make a difference. Make sure your pilot jet is clean and open, and that float level is correct. All of these adjustments work together.
Type at you later,
Dan McEntee
Is it 1-1/2 turns or 1/3 turn ? My book says lightly seat the mixture screw and then back it out half a turn. But i'm not sure if that means a half turn at a time or ?? My newer bikes for example say lightly seat the mixture screw and then back it out 2-1/2 turns.
There a lot of factors that change the way an engine runs. What ignition and timing do you have? What oil and ratio? What fuel? My Six Days has a 45 pilot jet, PVL at 2.6 btdc., Spector oil at 50 to 1, and 93 octane auto gas. The mixture screw is out 5/8 turn. It runs very well. Last week I needed fuel and dumped in some race fuel with 32 to 1 Yamalube. The engine bogged off of idle badly. I dumped this fuel out and went back to 50 to 1 and it runs great. I would have to reject to run 32 to 1.
Rick
Many things can influence mixture requirements, including all those mentioned above. If you are running the mixture screw in and out and nothing changes you may need to look deeper. Pilot jet may be wrong size for your set up or elevation. Double check float level. Also look at your "choke" plunger, I have seen several that were deteriorated and let excess fuel in.
the specs on the Bing type 84-2 28mm carb are as follows: they are also listed on the bag the carb came in from Germany (will post a pic)
135 main jet
2.76 needle jet
6G1 jet needle in position 2 from top
35 idle jet
air screw setting 1 turn out
ignition is a new HPI with timing at 2 to 3 mm BTDC. Fuel mixture is 33:1
any comments to these specs for a 1974 6-days 125 ?
heres a pic of the carb specs
https://photos.google.com/photo/AF1QipPcmueDbey090rCzc9lXxjSyAAeAC6czTAYIZu6
Is your carb for sure the Type 84 Bing? I think it came with the Type 53 but the 84 was the go fast hop up. I have better luck with a 273 needle jet and always use a NEW needle jet as they wear. I also use a #2 needle. I am not at all familiar with the needle you refer to. It almost sounds Mikuni. Also be sure slide is not worn a happy face in it.
Larry P
The spec you posted calls for 33:1 fuel mixture. That's probably the 1974 ratio. Modern oils allow you to use 40:1 and 50:1 ratios.
Steve Minor
Quotequote:Originally posted by Larry Perkins
Is your carb for sure the Type 84 Bing? I think it came with the Type 53 but the 84 was the go fast hop up. I have better luck with a 273 needle jet and always use a NEW needle jet as they wear. I also use a #2 needle. I am not at all familiar with the needle you refer to. It almost sounds Mikuni. Also be sure slide is not worn a happy face in it.
Larry P
Yes its a new carb I bought from Bing 4 years ago and its "type 84-2". the needle that Bing said is in the carb is the 6G1 - that's the term they used
Quotequote:Originally posted by Steve Minor
The spec you posted calls for 33:1 fuel mixture. That's probably the 1974 ratio. Modern oils allow you to use 40:1 and 50:1 ratios.
Steve Minor
Should I switch to the 40 or 50 :1 ratio ?? its not excessively smoking - is there a benefit to the higher ratio of fuel to oil ?
The fuel/oil ratio is an on going topic...many theories and preferences. Some people say oil burns slower, therefore creating more heat with a higher oil ratio. Other people say more oil means more lubrication. All I know is my Stihl chainsaw uses 50:1 at about 12k rpms...never had a failure. You might want to use the search option on this message board and read what other riders do.
Steve Minor
Thanks Steve Minor. I have used Stihl for over 20 years. No failures.
Ron Carbaugh
'74 6-days carb specs again. Can't get the bike started now and wore out my leg and wits. Can anyone please comment on the jet needle number from Bing ? Could this be right ? should I switch to a 140 main, 2.73 needle and 40 idle jet ? What are others running ?
135 main jet
2.76 needle jet
6G1 jet needle in position 2 from top
35 idle jet
air screw setting 1 turn out
That carb has a white plastic spring retainer...right? Make sure it's above the needle clip and not under the needle clip. I made that mistake once...drove me crazy until I disassembled the carb and figured it out.
Steve Minor
Yes I put the plastic on top of the needle holder - it was incorrect from Bing to begin with
Quotequote:Originally posted by Larry Perkins
Is your carb for sure the Type 84 Bing? I think it came with the Type 53 but the 84 was the go fast hop up. I have better luck with a 273 needle jet and always use a NEW needle jet as they wear. I also use a #2 needle. I am not at all familiar with the needle you refer to. It almost sounds Mikuni. Also be sure slide is not worn a happy face in it.
Larry P
The jet needle is Bing part number 46-290-6G1. They no longer use #1 or #2 designation. They are telling me the correct one (taper) is the 6G1
https://photos.google.com/share/AF1QipP9-8lleWXIZ0jkc8S66Hs7JihuAgEsI_f-XTh0rE3Z_abvh4ozcU9bexUnCmFOkg/photo/AF1QipO9NIaSW9ifPjRA9GjUbFT2NeM88Y5JQk2HoAGf?key=MFlBU3o1bFRULTN4Rmdwek45V0hzMnFfbTRUUU1n
This is the Package as shipped from Nurnburg
Are you overseas? If not Bing stuff is available from Bing here in the states out of Kansas. Great guys there.
Larry P
Quotequote:Originally posted by Larry Perkins
Are you overseas? If not Bing stuff is available from Bing here in the states out of Kansas. Great guys there.
Larry P
I did order from Bing USA but they sent the carb from Germany
Here's some interesting info on the Bing Carbs
Technical Information For bing carburetor Adjusting the Bing Carburetor - The Bing Carburetor has a three stage system: Idle, Midrange and Top End. Idler Jets - From the moment the engine is started to approximately 1/4 throttle, the carburetor is running according to how the idle system is set up. As the idler jet number decreases, the mixture gets leaner as the number increases, the mixture gets richer. For instance, Idler Jet #45 has a leaner mixture than Idler Jet #50 The Air Regulating Screw must be set as stated in the Bing Jet Chart in order to insure smooth operation of the Idler Jet. This screw adjusts the air/fuel mixture at idle speeds and for smooth acceleration. Turning the screw in a clockwise direction creates a richer mixture while turning it counterclockwise creates a leaner mixture. To adjust this screw, gently turn in a clockwise direction until the screw bottoms out, then loosen the screw (in a counterclockwise direction) the number of turns as recommended in the Bing Jet Chart. (effective range 1/2 to 2-1/2 turns out). Use the carburetor piston Adjusting Screw to adjust the idle RPM. Turn this screw in a counterclockwise direction until the Carburetor Piston is in the lowest position. Then carefully turn the screw clockwise until it just engages the piston and then continue to turn it clockwise for 2 to 2-1/2 turns. This determines the idle RPM. of the engine and should be set at 2,000 RPM min. Needle Jets/Jet Needles - The Jet Needle has three or four grooves which the clip can be snapped onto. The grooves are 1, 2, 3, 4 with number 1 at the top position . When the clip is snapped onto the top position #1 of the needle, a leaner mixture is created than if it was mounted on the #2 groove. NOT: Jet Needle clip must always be under plastic spring cup. The Midrange System affects the carburetor for approximately 1/4 to 3/4 throttle. Once again, the lower the needle number of the Needle Jet, the leaner the mixture. Main Jet Conversion Chart - The Jet chart shows each engine and the stock caburetion setting at sea level. If you live other than at sea level or in a hotter climate, then you must refer to the Main Jet Conversion Chart to calibrate for altitude and temperature. Air density decreases with decreasing pressure and increasing temperature. If an engine is operated at higher elevation, the weight of the aspirated air decreases, where as the aspirated fuel quantity remains practically the same. This results in richer fuel/air mixture than the lower sea level. If the engine is operated in high altitude for a longer period, it is necessary to adjust the carburetor calibration to re-establish the original composition of the fuel/air mixture. With increasing altitude (lower air pressure), the oxygen quantity injested by the engine decreases. The consequent loss in performance cannot be compensated for by different carburetor settings. To adjust the carburetor, in general, a different main jet size is sufficient. Only in very particular cases does a different needle jet and/or different idle jet have to be installed. Example: If a single carb engine set up for sea level is shipped to Colorado Springs, Colorado, (approximate elevation 6,500 feet), the main jet would have to be changed. The carburetor would have a main jet of 180 at sea level. By using the conversion chart, going to the approximate altitude of 6,500 feet and using the temperature of 32 degrees, you can see we have a multiplier of .95 and come up with a recommended jet of 171. This main jet will produce the same composition of air/fuel mixture that the 180 main jet would at sea level