Topic: 78 cb750k

[linktothepast23]

yeah my mistake! I thought the tube that ran down the engine was the emulsion tube :p which probably should be cleaned right? how would I go about doing this?

so this is weird, I just hooked up my spare fuel petcock that I had purchased just because. let her warm up went for a drive...AND NO STALLING! nice smooth shift. wtf? maybe it's just coincidence but it's acting great now. I'm stumped...

I still want to adjust ims but geez this thing is running pretty damn well 

[flybox1]

Unless YOU pulled and cleaned the lets and emulsion tubes, I'd look into getting this done asap.

[linktothepast23]

Could a non fully warmed up bike cause this problem?

[Mr. Mike]

"Could a 'none fully warmed up bike' cause this problem?". This caught my attention and was a thought of mine way earlier in the thread. Kid you not, I've got to let my 78 warm up at 2K rpm for at least the time it takes to gear up for the ride. Jacket, gloves, helmet, set up the phone and Bluetooth and then close the garage door. Sounds like 8-10 minutes at least. If not warmed up for maybe at least this amount of time, she'll stumble on acceleration for the first few starts and then all is fine. I've got a friend who is trying to get me to dump these PD carbs for earlier style to simply "start and go".

[lrutt]

You guys need to confirm your accel pumps are working proper. On mine, the small diaphragm did not have a hole punched in it to allow fuel to flow so consequently it was inoperable and had the same problems you describe. I punched that hole and voila, accell pump working and problems solved.

[lucky]

let me rephrase what I said earlier, when coming up to a stop sign she idles fine. It is only when I start accelerating that she wants to act funny, but once she is over say 3 rpm she starts picking right back up and everything is fine. It only does this after the first couple stops.

ALL tuning should only be done when the bike is fully warmed up.
Making any adjustments while the choke is on or partly on will be counter productive.

[brewsky]

You guys need to confirm your accel pumps are working proper. On mine, the small diaphragm did not have a hole punched in it to allow fuel to flow so consequently it was inoperable and had the same problems you describe. I punched that hole and voila, accell pump working and problems solved.

+1....Same here

[linktothepast23]

When I tuned it I rode around for a good 15 min before I started work. Also how do I punch a hole through the diaphragm? Is this a simple task or will it take me most of the day?

[martin99]

If you take out the accel pump diaphragm you'll see it looks like a silhouette of Mickey Mouse's head. Each of Mickey's ears should have a hole in it to allow the fuel to flow through. You'll see what I mean when you get to it Easier with the carbs off I would think. If it's not salvageable you can get a new one.