RB30 Bad Cold Idle

[GQ TANK]

Quite often idle issues on the rb30 or tb42s carby point to a need for a carby rebuild. (both carbys a nearly the same and use the same rebuild kit.)

I have experienced issues with the rb30 and tb42 of poor idle / lost of power being caused by the middle part of the carby coming loose. Simple way to check, remove the air cleaner and lpg mixer (if fitted), Grab the top of the carby and give it a shake - there should be no movement. If there is movement, pull the carby flip it and tighten the 3 brass screws.

[dom14]

Quite often idle issues on the rb30 or tb42s carby point to a need for a carby rebuild. (both carbys a nearly the same and use the same rebuild kit.)

I have experienced issues with the rb30 and tb42 of poor idle / lost of power being caused by the middle part of the carby coming loose. Simple way to check, remove the air cleaner and lpg mixer (if fitted), Grab the top of the carby and give it a shake - there should be no movement. If there is movement, pull the carby flip it and tighten the 3 brass screws.

Yep. After a while(especially after installing a rebuild kit), it's a good idea to pull the carby out & re-tighten the three bolts.

The float needle of the backup carby's looked pretty strange when I pulled it apart. The needle is actually a ball end. It works fine, but I haven't seen a ball end float valve before.
Google confirmed they do exist and not that uncommon. Uncommon for a Nikki carby for sure.

I went to the trouble of making my own gaskets for the float chamber as well. Quite an experience with craft work.
I didn't want to spend $80 on a rebuild kit, just to get the gaskets( No body sells the gaskets).

With carby's, each time you pull apart the same one, you learn something new and valuable.
It's too bad they are out of date now.

I still think a backup carby is more reliable than not being able to fix parts in an EFI system, when I'm stranded in the middle of nowhere.
That's the reason I haven't been that proactive with the EFI conversion of my RB30.
But, many pro mechanics disagree with me. Carby's are way too much trouble they say.
I think, if I learn to fix them, it's not that bad at all. These skills come very handy in the bush.