Question about air/fuel ratio... I think

[drum4fun76]

Hey guys,
Wasn't sure where to post this so I'll just ask away and maybe someone can re-route this later. I'm a new member and own a '76 CB. I've been working on it for a couple of years now adding and substracting until I was happy with the end result. I ended up with a rigid bobber with foward controls, 12' apes and a right side tank shift. The only thing is that I only got to ride it this fall at the end of the riding season (I live in New-Brunswick, Canada - it was -4 F yesterday). I rode it a few times before storing it for the winter and it wasn't running properly. Everytime I'd turn the throttle past halfway I'd loose power. It sounded like too much air (air/fuel ratio). I'm running 4 into 1 exhaust pipes and 4 air filter pods. I tried bigger main jets and it helped alot, but I was wondering if anybody had other ideas as to how I could fix this problem? Is there anything else that I should be doing or checking? Any suggestions would be greatly appreciated. I love to ride, but I'm no mechanic. By the way, the motor and carbs are stock (except for those main jets).
Cheers!

[shinyribs]

Sounds like you are on the right path. Probably needs more fuel yet. What size jets did you start with/ end with? I had the same issue on mine and it took a couple times of jetting up before it came out right on the plugs. I didnt realize how flat my low/midrange was until i upped the pilot jets too. Something to consider. I'm guessing you have the round top carburetors on your bike? Just for comparison,my bike has pods and 4 into 1 with a very free flowing muffler. I ended up with 125's in the mains and 42's in the pilots. Im not sure that it couldn't use just a touch more in the pilots,but I think it will work for year round pretty well.

[TOOLS1]

Ditto what Shiny said. How about some pictures?
TOOLS

[Re-run]

When you close the throttle like that, you move your primary circuit back to the idle. You most likely need to do 3 things. Your air screw will probably need to be turned in, this is to fine tune. You will need larger idle jets. And you will probably need to raise the needles in your slides 1 notch.
Start with the jets, once those are working ok, tune with the air screw. At that point, if you run into transition issues from idle circuit to mains, then raise the needle.

[Lucky 1]

Just changing the mainjet isn't going to do it.
ALSO- IF you have pods there is almost no difference between pods and stacks.
Check this out... Pick up one of your pods and suck on it. See no resistance at all.
Just like velocity stacks.

You did not say what the stock mainjet was and what you increased it to.

First you will need to increase the idle jet size from stock. Just go up one size.
Meaning if it is a #35 then go to #40.  0 up to 1/4 throttle is controlled by idle jet and mixture screw.
Adjust the mixture screw. After it is warmed up just turn the mixture screw on each carb until the idle goes up and back it off 1/8 turn. BTW...since you will increase the idle jet size one step, then set the mixture screw to the minimum amount (specified in the manual).

SECOND... You will need to raise the needle in the slide to richen the mid range
by lowering the clip on the needle ONE notch from stock. 1/4 up to 3/4 throttle.
One notch will be just right.

THIRD....Mainjet is for wide open throttle in high gear which you would mostly
be using on the freeway.
In high gear it should just keep accelerating. If it seems to hit a flat spot then
increase the mainjet size.

Since you have already increased the mainjet size I would just work on idle and needle now.

If you quickly open the throttle and it coughs or stalls it is still too lean.

[drum4fun76]

Thanks guys.
alot of good points. Didn't think about pilot jets or needles. I know this sounds stupid, but I can't remember the exact sizes of jets I put in last fall (I had bought a kit and there were a couple of diff. ones.) and since I'm buried in snow, I'll have to check this spring.
I inserted a couple of pics of my '76 and of my '78 GL 1000. They're not the most recent, but they're all I could find at the moment. The GL will be getting some work done to it including a cafe fairing andnew angled exhaust pipes. I'm also planning on working some more on the bobber like installing a Dyna ignition system.

Keep the good info coming... I'm taking it all in.
Cheers!

[shinyribs]

It's not too hard to just get at the jets. Just pop the bowl off and a stubby will reach them. When I was tuning mine I took the stuff with me and was swapping out on the side of the road. Of course,I'm sure you know how to get at your jets,wasn't trying to say  that. But the main thing is...I WANT YOUR GL ! That thing is sweet!!!!

[drum4fun76]

Thanks shinyribs, I just don't feel like shoveling a path to get to my shed to get to the carbs to get to the jets. I'm glad you like the GL. It's not everyone's cup of tea. I bought it from a guy who had left it on it's side stand since '92. It was fully dressed when I bought it. I won't tell you what I had to do to get it to where it is now (list too long). I can tell you that where I live, I'm pretty much the only one driving a naked GL. But enough about that. This is, after all, a CB 750 forum. Thanks for all the advice.
I'll post more pics later.
Cheers.

[shinyribs]

I can understand not wanting to shovel out there. I hate snow. The first time I saw a naked GL I didnt know what it was.i just knew i liked it.When i found out it was a stripped goldwing i was amazed! Wow,those big monsters can look that good?!?!LOL.I want to build another bike just for cruising and passed up a good deal on a early 80's gl motor for $250,cuz i didnt want a liquid cooled bike. Seeing your bike makes me regret that big time! All there is around here is H-D's and full dressed GL's. It may be my only option