Topic: 1975 cb750 carb problems again

[jamesb]

i broke down took my carbs in to have gone throughcost a arm and a leg. did some research on pods and such tiold the guy to put in 125 main jets he did idle jets where 40 set the needle at 4 well it runs even worse than it did before.i was running pods took them off and put on the old santee breadbox breather.what it does is idle then give it gas it kinda backfires and dies.it runs fine at idle until you give it throttle.  i'm taking them back tomorrow what should jets should i have put in instead of the 125 this engine has the 836 kit in it open drag pipes

[harisuluv]

Hmm well usually that kind of popping on acceleration indicates a rich condition.  Unfortunately I don't think anyone will be able to hit the bullseye over the internet on the first try.  Did you take it into a local shop?  Just out of curiosity what did he charge you?

[lucky]

I feel sorry for you that it cost all that money.

The idle jets will need to be #42's

You could change main jets all day long with no effect on your problem.
The problem is the transition from idle to 1/4 throttle.
You also need to experiment with the mixture screws. 1/8 turn cam make a difference on these carbs.

Pods and open drag pipes.
WHICH  CARBS? 7A or 657A'S

WERE not where.
EXAMPLE: Idle jets were 40 mm.

QUOTE:
"i broke down took my carbs in to have gone throughcost a arm and a leg. did some research on pods and such tiold the guy to put in 125 main jets he did idle jets where 40 set the needle at 4 well it runs even worse than it did before.i was running pods took them off and put on the old santee breadbox breather.what it does is idle then give it gas it kinda backfires and dies.it runs fine at idle until you give it throttle.  i'm taking them back tomorrow what should jets should i have put in instead of the 125 this engine has the 836 kit in it open drag pipes

SHOULD BE:
I broke down and took my carbs in to have them gone through.It cost an arm and a leg. I did some research on pods and such. I told the guy to put in 125 main jets which he did. The idle jets were # 40 mm's. I set the needle at 4th groove from the top. Well it runs even worse than it did before. I was running pods took them off and put on the old Santee breadbox breather. Now what it does is idle then I give it gas it kinda backfires and dies. It runs fine at idle until you give it throttle.  i'm taking them back tomorrow. What main jets should I have put in instead of the #125 mm's? This engine has the 836 kit in it open drag pipes.

[lucky]

Hmm well usually that kind of popping on acceleration indicates a rich condition.  Unfortunately I don't think anyone will be able to hit the bullseye over the internet on the first try.  Did you take it into a local shop?  Just out of curiosity what did he charge you?

Well I can get real close.
When you try to give it throttle from idle and it backfires,quits running, or bogs,it needs a larger idle jet if the mixture screw adjustment will not fix the problem.

[jamesb]

hey thanks for the grammar lesson when you suffer serious head injuries.some things in life are hard to deal with.

i paid $201.56.to have them rebuilt. i'm sick and tired of the this bike, i'm burnt out with people, the bike is now sitting outside behind the barn where it can rot.

[Jerry Rxman Griffin aka MuthaF'er]

Jimmy, hang in there bro. Carbs are an aggravating nuisance, huh! That bike is too nice to give up on. Why did you settle on 125's? I believe stock for 75 is 105. The 75 K's don't use much of a cam. Just adjust one circuit or make one change at a time. Did you change jets and the breadbox at the same time or change the jets, see what it did and then change to the breadbox because it still wasn't right? Perhaps Lucky's suggestion about the bottom end is a good place to start before doing the top end. 

Guess Lucky is either an anal high school grammar teacher or perhaps he should've thought about people's possible issues like the bike wreck that damn near killed you. Two bad spell checkers can't also be grammar checkers to. I wonder what Lucky's problem is?! I'm thinking Lucky should offer up a public apology for his grammatical "help"!

[jamesb]

hello jerry how ya been.

i did some research and what i found for the setup that i have is to use 125 jets for pods/airbox and drag pipes. the idle jets where 40's in the bike already i thought i read to run 40's i did turn my mixture screws a 1/8 turn it helped at least i can give it throttle nowb but when giving it a wide open throttle it does back fire through the pipes now not through the carbs anymore.i'm at wits end with a lot of things now and this bike and comments that people make have pushed me closer to the edge.