New Slide Needles

[squish]

I've completed my first top-end rebuild on my '84 RZ350 US model. I also rebuilt the carbs, refreshed the PVs, put in new fuel and oil lines, plugs, coolant hoses, repainted cylinders and heads, and maybe other stuff I'm forgetting.
I'm attempting some heat cycling and she's running rough. Both cyls are firing right up. It was suggested that my new slide needles could be to blame. I didn't adjust air screws or jets other than replacing the main jet (which takes no adjustment). Carbs ran great before the refurb and they are visually balanced perfectly. Symptoms are having to keep the bike on choke for it to run and when off choke, the RPMs have to be blipped up around 4-5K to keep her going. Would experimenting with slide needle positions be a good start? Or am I barking up the wrong tree?

[justind97]

Do you have the idle screws set properly?

If the carbs ran great, then it was something you did. Which means taking them apart to see what you missed.

Needles at this point are not the issue, you have something else wrong.

[MK]

If it ran great, why did you screw it up. Never heard "never touch a running system" or "if it aint broken, don't fix it"?

Usual causes:
- swapped float bowls left/right (unlikely in your case as it started)
- forgot to put the vacuum line on the right carb (likely for your symptoms)
- too few fuel, too much air in the idle system = wrong size idle jet, air screw too far out, float level too low, air leak.
- used a yambits carb screw up kit err... i mean repair kit: get out all of it and use the stock parts (my advice anyway: go back to the last running state)

[squish]

Is the vacuum line from the other carb the one that goes to the second nipple on the petcock? How does that all work if I'm using an auxiliary tank?
If it doesn't resolve itself I'll utilize the manual for air/idle screw info. Thanks

[gpaddict]

if you are running off of an aux tank, did you plug the vacuum line?

[squish]

if you are running off of an aux tank, did you plug the vacuum line?

No! Didn't know to do that.
The shiny new vacuum line is just coiled up on the side waiting for the tank to be mounted.
I hope that's the problem.

[RuZty]

That would definitely constitute an air leak.

[squish]

Wouldn't you know... I clamped the vacuum line and got a nice warm up. Ran her for about 5 min. Smooth and sounds really good.
Now I need to find a thread about thermostats.