Carb adjustments

[iliketoride]

I need some help adjusting the Bing on a 125 six day. What changes does moving the needle up or down in the slide make? Plugs foul before i can even get 'er running. Any other carb setting info. appreciated.

 

[Paul Danik]

Moving the needle up in the slide will richen your mixture. Lowering the needle will lean out your mixture. If you are fouling plugs you may have a rich mixture,BUT!!!!! I would also check out the aircleaner before I went to adjusting the carb. There are more areas that can lead to your problem, but I would check the aircleaner, and then lower the needle all the way to see if even makes a difference. Let me know how you make out.
Paul





 

[iliketoride]

Thanks for the reply Paul, however the filter doesn't seem to be the prob. I made the needle adjustment(down)to lean the mix and got 'er started but wont run for more than a minute then stalls. It still seems to be flooding and slobbering all over the place. How are the floats properly adjusted?

 

[Paul Danik]

I would turn on the fuel and let some run into the bowl. Then shut off the fuel from the tank and fire up the bike. Without any fuel running into the carb it should fire and  run, see if it clears itself out as it runs out of fuel. If it does clear out then the float might be the problem.  First thing is to see if the float is full of fuel.  Sometimes they will fill with fuel and then it will not float up and shut the fuel off.  If the float has fuel in it ,it needs to be replaced. Just remove the float and either look at it up towards a light or shake it and try and feel if it has liquid in it. The float level is checked by holding the carb upside down and seeing if the flow stops when the float is level with the carb base. I will blow through a fuel line as I lower the float  to see when the flow stops.The float is adjusted with the small tab by the needle. I have also seen the needle and seat wear and leak, or have a piece of dirt in it.  If your carb has any cloged passages it will also drive you batty. Good luck.  Paul

 

[Don Roth]

I also suffer from a rich running carb on a 125, I am hoping the replacement float I ordered from BING (1-800-309-2464) solves
the problem, I feel that mine gets 'gaslogged' and then floods the bowl. Pretty
reasonable price (~$15.00)

[Bob Gilman]

Larry Perkins has all the carb. parts also.Probably cheaper.           [email protected]

[Dave H.]

I was so frustrated with a similar problem I nearly took a hammer to the bike...until someone asked if I had cleaned my silencer...DUH! As soon as I took the silencer off, the bike  ran like it was new! Easy test to determine if it's carb related...remove both airfilter and silencer., and fire her up. 2 strokes are air gulping fire breathing pumps and if they can't inhale and exhale, they choke.
Good luck,
Dave H

 

[Chris Brown]

I had this problem too. Got a new float needle from Bing, the kind with a rubber tip on it so it seals well even if the seat is a little worn.
The air mix screw is very critical. Mine runs best about a third turn out from closed. More than that and it backfires and runs very poorly. The farther out the more it leans the engine, but it will sound like it's loading up becuase there's too much air for it to run properly.
A fouled plug will re-foul quite quickly. A B8HS is a little cool, I'm going to a 7. But then I'm running the old Bosche points ignition and I hear the spark isn't quite up to modern standards. May even go to a 5 or 6. Makes carb tuning that much more critical.
I always get rough tuning done without aircleaner, then re-adjust for riding conditions with everything hooked up.

The slide needle regulates fuel from throttle settings off idle to 3/4 throttle (approximately) then the main jet takes over. The main jet will affect the needle jet too, but to a smaller degree. The idle jet and and airscrew affects idle and throttle response.
Proper setting for the needle is 2nd notch from the top. Then adjust from there for fine tuning. If the needle and jet are worn, which they do where with extended use, it will richen the mixture off idle and load up your mid-range.
A worn float needle will let fuel flow with the engine shut down and can actually overflow into the engine. I've had to turn a bike over and kick the engine over with the plug out to clean it out. And it makes the float level unreliable because it keeps flowing even when the bowl is full.
 
A 2 stroke run too rich will foul the plugs and carbon up the combustion chamber. Run too lean it will overheat and seize.
Also, if you're running a synthetic blend, like Golden Spectro, mix it at 40:1. Too much oil will lean out the mixture and smoke a lot.
In many cases I have seen symptoms that act like the opposite that they are; lean vs. rich.
Let us know how your doing with it.
Chris.

 

[iliketoride]

Thanks for all the info. and help. I fixin to hand it over to a local shop. I have only limited knowledge of the 2 stroke beast and their pesky carburators. The only problem now is how to get rid of the gasoline odor on everything i own??

 

[Gavin Housh]

Have you checked the rubber tip on the end of the starter slide ass'y (choke).If the rubber on the end of stater slide is deteriorateted or even completely gone in some cases, it won't allow the enrichment passage (choke) to close. Thus allowing a constant over abundance of fuel to be supplied to the mixture. This problem is easily checked. Take an 11mm wrench and unscrew the screw plug (cap) where the choke cable enters the carb. Once you've got it loose simply pull the cable and the whole ass'y comes out. On the very end of the cable is the starter slide. The end of the slide should have a circular inprint in the rubber from where it seats. If the rubber is at all detereorated throw the starter slide away and buy a new one. The stock jetting should get you running. If you have to change the jetting a little here or there that's ok, but using a hotter plug is not considered a smart choice by professional tunners. You may also want to make shure that the crank case does'nt have an over abundance of residual fuel down there. This situation occures when one or more problems keep the motor from starting, and when the motor loads up or floods with fuel it all runs down into the crank. There are several ways to clear this fuel out, but the most efficient way is to remove the spark plug and turn the whole motorcycle upside down and then crank the kick lever buy hand repeatedly untill no fuel comes out. I know this sounds crazy but somtimes desperate measures must be taken. If you use this method drain the fuel tank and carb first or you'll have the garage floor covered in flammable liquid. Get a friend to help and use some old pieces of carpet or cardboard to protect your handlebar/controls and seat/rear frame tubes from abrasion. You'll also want to put some shop rags under the spark plug hole to catch any fuel that does come out. This keeps fuel off the coil as well as the underside of the gas tank. Good luck. Gavin

 

[Dave H.]

Good point! ...the enrichener was a problem on both my 125 six dayers, and I found that I didn't need one to start my Pentons even on the coldest mornings in the NW, so I soldered a piece of solid 12 awg copper  wire into the brass pickup tube (the long tube inside the float bowl) to plug this system. I can easily unsolder and remove the plug to restore the enrichener, should the need arise.
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   SAFETY ALERT: Be sure to short out the high tension wire before trying the method suggested below for clearing flooded engines! This way you won't ignite the fuel which runs out and ruin your whole day.
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quote:
... You may also want to make shure that the crank case does'nt have an over abundance of residual fuel down there. This situation occures when one or more problems keep the motor from starting, and when the motor loads up or floods with fuel it all runs down into the crank. There are several ways to clear this fuel out, but the most efficient way is to remove the spark plug and turn the whole motorcycle upside down and then crank the kick lever buy hand repeatedly untill no fuel comes out. I know this sounds crazy but somtimes desperate measures must be taken. If you use this method drain the fuel tank and carb first or you'll have the garage floor covered in flammable liquid. Get a friend to help and use some old pieces of carpet or cardboard to protect your handlebar/controls and seat/rear frame tubes from abrasion. You'll also want to put some shop rags under the spark plug hole to catch any fuel that does come out. This keeps fuel off the coil as well as the underside of the gas tank. Good luck. Gavin