Need help with Carb tuning (southern WI)

[ehletra]

Hi My six day is running like carp and I some help geting it tuned up im located in fort atkinson wisconsion so if you could please help me get it tuned please reply
thank you travis

[ehletra]

No I dont realy know the jetting specks or any thing it could pry use a carb kit its very clean and I have good Gas in it. Iv been driving it today quiet abit and it seems to be fixing its self. Would you know where to get the carb kit for it and its all origonal from top to bottom
Travis

[farmer58za]

Hi Travis
Go to: http://groups.yahoo.com/group/PentonRestorationandTechGroup and look in the files section. There's a section on carburetion and you'll get the spec's there.
Regards
David in SA

Regards

David ('75 KTM GS400)

[tmc3c]

Hi Travis, I noticed that you posted a while back that you are running your oil mixture 20/1 with a cheap brand of oil and you said it would run better this way.What I was wondering is what your plug looks like now after running it a while and if you have changed your plug while having this problem. It could be the carb sure enough but I was just trying to see if there would be a EASY fix.

Thomas Carmichael

[ehletra]

No its not the plug for sur I have replaced it and it would do the same thing.
Travis

[john durrill]

ehletra,
If you have a 125 B engine then these jets should be close.
Main jet 140 or 145
Needle jet 276 ( if this is whats in it, get a new one they wear        
fast and cause a rich condition)
Pilot jet 40 or 45
Start with the needle clip in the center groove.
 Turn the idle mixture screw in till it bottoms ( be easy lightly bottom it) and back it out 1 and 1/2 turns. Adjust this setting for best idle after the engine is warmed up (about 15 mins)
The 45 pilot and the 145 main jet are a little large but if you are running 20 to 1 oil mixture you may need the larger size.
Check the float level. The little brass tab should just touch the float needle as the float becomes level with the carb body. You can use a piece of fuel line attached to the carb and blow through it lightly. The float needle valve should shut off the air as the float comes level with the carb body. If it does not seal then the needle and or seat need to be replaced.
 Look at the little piston that the choke cable operate's. Its under the adjuster that the choke cable goes through on the carb.  The end that seats with the carb body may be soft and not sealing. That would allow air to draw extra fuel from the float circuit with the engine running and the choke lever off. Look at the front bottom 1/4 of the slide. On the outside of the slide, if you can see and feel a happy face step worn in the slide then you need to replace it. The slide does not seal well like that and will drive you nuts jetting.
 I can scan the instructions for adjusting your carb and send them to you if you will E-mail me.
Hope this will help you,
John D.

[ehletra]

Thanks for all the info John It turns out I need a new carb!! Wheir would the best place to get the parts at for the cheepests price or should I buy a different carb off ebay. it is a 125 6/b engine. The carb  is very wron plus it sat for 15 years with gas in the bowl and croded it  (Its been cleans acourse)

[john durrill]

ehletra,
 I would have to see the carb to know what you need. Try Al B. for any parts he has or Donny. Then you can get most things from BING for the carb if they dont have it. Someone may have a good float bowl they would part with if that all that is damaged. Is the body in good shape?. The jets are easy to find. The slide could be a problem. I would try Al and Donny on that first then BING. The needle is steel. Is it rusted or pitted where it goes into the needle jet?
 The carb is a bored out 27 mm as I remember. Its something like 27.5 mm ( max size that carb body would handle). Maybe someone like Ron can supply you with one that is rebuilt and in good shape. We have not had good luck on Ebay for things like this. We average about 60% in getting what we paid for.

Here is BINGs web page. They are good people and helpfull.
http://bingcarburetor.com/
John D.

[ehletra]

well the boady is great I pry need a new main and choke slide and the jets are easy to get at and all I just need parts. what fule mixter should I run in It

[john durrill]

ehletra,
It would depend on what oil you plan to use. We run either golden spectro or maxium M at 40 to 1 in our bikes. But both these oils are made to run at that mix. What oil are you planning on useing and at what mix? More oil means less fuel and that means slightly bigger jets depending on the temp and altitude.
  Look over the slide if its not worn or the needle pitted or stepped with wear then get a new jets, a float bowl gasket, new float needle and replace the choke piston.
 A 276 and 273 needle jet , a 35 , 40 , 45 pilot jet and a 135, 140, 145 main should let you tune the carb for almost any oil to gas mix you choose.
 make sure you dont have any air leaks and the pipe is clean. The exhaust flange needs to be tight and sealed on the cylinder also. Check the air filter and make sure its clean and its not over oiled. Its easy to get too much oil on one after cleaning and it takes while for the oil to clear ( either drip off the filter as the bike sets on the stand over night or by running the engine or both). The bike will run rich till the excess oil leaves the foam.
 Always start out rich when you jet and work down. That way you dont run the risk of seizeing the piston. Get the bike hot , at least 15 mins before you change the jetting. After you change the jetting run the bike a bit and re-adjust the idle mix . It affects throttle response just off idle and when your running off the pipe. Then ride the bike some and you can tell how much of a change you made. Re-adjust the idle mix often till you get the best idle after rejeting. The idle mix screw should most times end up be between 3/4 to 1 and 3/4 of a turn out from bottom.
 Let us know if we can be of help.
John D.