Topic: '74cb 750 idles but dies with any throttle input.

[Puntas13]

How it sits.

Uni Pods
Stock headers w/glass pack
#42 Pilot #120 Main. Both new.
Bench Synced.
Tappets adjusted.
New tec points.
Timing Set.
Fresh Gas.
26mm Float level.
New Plugs/Coils.

Im going crazy trying to figure this out. The bike will idle, but giving it any throttle input will immediately kill it. It will respond to throttle input with the choke on but it seems slightly erratic. Number 4 seems to be running cooler.

I've disassembled and cleaned the carbs 5+ times. Although i haven't pulled the sliders and needles out.

Needle height is the only thing I can think of. If it was set too low would it affect it like this?

For the love of god is there anything I'm missing?

[lucky]

How it sits.

Uni Pods
Stock headers w/glass pack
#42 Pilot #120 Main. Both new.
Bench Synced.
Tappets adjusted.
New tec points.
Timing.
Fresh Gas.
26mm Float level.
New Plugs/Coils.

Im going crazy trying to figure this out. The bike will idle, but giving it any throttle input will immediately kill it. It will respond to throttle input with the choke on but it seems slightly erratic. Number 4 seems to be running cooler.

I've disassembled and cleaned the carbs 5+ times. Although i haven't pulled the sliders and needles out.

Needle height is the only thing I can think of. If it was set too low would it affect it like this?

For the love of god is there anything I'm missing?

The fact that if you give it choke and things improve means that it is starving for gas.
You must deal with the needle height. Lower the needle clip one notch from the stock position.

Also it was not mentioned, but turn the idle or mixture screws out one full turn from closed.


You are close.

[Bootlegger56]

How much fuel is in the bowls when you pull them or drained them 5+ times to clean them out?  Are they semi full?  Did you clean the petcock screen and petcock?  I guess my point is that.... is it getting gas from the tank to the bowls?  I will assume you timed it at the "F" mark and set the valves at the "T" mark.  Did you clean the points before setting them since they are new?  How was it running before you did all of this maintenance?

[Puntas13]

Well i got it all fingered out.

The bike was a non runner when i picked it up and already had the pods/exhaust and no stock airbox.

It was the culmination of several things as far as i can tell. I pulled the needles and they were shimmed to low. They were clipped in the second spot from the top. I moved them down to second from last. I put some better hose clamps on the intake gaskets and cranked the #$%* out of them.

It idles much better and will accept throttle input without dying. Revs good. Still need to work out the fine details with air/fuel screw but overall I'm satisfied.