Topic: CB750K float adjustment "never seen this before!"

[flybox1]

You need to get a set of clean plugs, pack some tools, and go replicate the hi cupping you are experiencing.  Hold and keep the bike in this state for good deposits to form on the plugs. 2-3 minutes will suffice.  make a mental note of your throttle position.  1/2, 3/4, wide open...etc.  When you have the space, and it's safe, kill the bike and pull the  clutch at the same time.  Coast to the side, and pull all your plugs.  Take a picture of their tips, and post it here.

[lhemrick]

Thats the plan. Black-rich, white-lean, light brown tan-just right! But what I don't understand is if it's a jet problem why will it take off and go under a hard throttle but hold constant speed trying to just cruise?

[seanbarney41]

you gotta raise or lower your needles

[flybox1]

Yes...it sounds like a needle height issue, .but all of your jettting overlap so you can't just change it as it will effect mixture at other throttle positions, too.

You cant just assume your main jet is right, you need to do a plug chop to see, then, once jetting is  correct(ed), proceed with a plug chop for mid throttle....which will tell you lean or rich through the needle jet.
 a plug chop for up to 1/4 throttle is performed to get your pilot jet right.
Then a check for idle mixture....

Don't assume the jets in there are right just on your butt dyno alone...

[lhemrick]

Thanks what I was afraid of! These coffin top carbs are going to be a pain in the a$$ to make that change, aren't they?

[750K]

Not really, I have never had a problem accessing the slide and removing the needle with the carbs on the bike. Once you do it once its fairly simple, you just need patience.

[flybox1]

Not really, I have never had a problem accessing the slide and removing the needle with the carbs on the bike. Once you do it once its fairly simple, you just need patience.

+1
There are some small parts.  Just work on a towel so isht doesn't go flying or rolling into the abyss.
Chill, and have a beer while you're doing it.  No need to make it harder than it is. 
Do one at a time.

[750K]

I've always found that there is an order to which of the two screws you remove first on the arm that holds the needle down. It's spring loaded, so once you start loosening them you can't get the screw driver on one of the heads due to the plate springing upwards. The right size of Phillips or jis driver is important, the last thing you want to do is strip one of those screws. I had a #$%* of a time getting one out a PO had almost totally stripped.

[lhemrick]

Thanks Guys! I've in the shop playing with a spare set of carbs I have and I see it shouldn't be to difficult. If it will quit raining long enough for me to do some plug chops to see what it needs and I can get this 350 twin engine back together and out of the way maybe I can get this thing running right again.