[Slambow]

G'day there. So my 1.3 carby was giving me the shits with a really rough/surging idle when hot. I was almost ready to not be such a tight arse and take it to a mechanic. Anyways I tried the revving and smothering the carb trick, checked/cleaned the solenoid, pulled the mixture screw out and blasted in there with carb cleaner to no avail. I pulled the carb off and took the top off it, not losing anything which is a first for me, carby cleaned everything I could see, pulled out the idle jet and cleaned that and the solenoid- again. Put it all back together and it was the same cracked the shits and left it. Pulled the carb top off again today, pulled the idle jet out and it looked clean, but cleaned it anyway. Then I checked the float height, which was too high. Adjusted to fsm specs, re-assembled and she idles like a dream. My question is- is it possible the float height was causing the rough idle? Or just a blockage? Inside the carb is clean as, and I don't really think I was doing much emptying half a can of carb cleaner in there. Well I didn't see a blockage come out anyway. It's fixed now but I'm curious to know?

[Marko_SJ]

With motorbikes, I have heard improper float height can change the jetting.

Too high of a float height can change the jetting to make it rich.

Coversely, too low can cause you to run out of fuel / run lean.

The carb cleaner coupled with compressed air works great for me.

[Slambow]

Yeah, I've re-jetted the carbs on the bike and had the joy of setting all 4 floats the same height! I used heaps of carb cleaner but didn't have the air compressor, maybe that was the problem. Just wondered if anyone else has had trouble with float height

[Marko_SJ]

Slambow wrote:

Yeah, I've re-jetted the carbs on the bike and had the joy of setting all 4 floats the same height! I used heaps of carb cleaner but didn't have the air compressor, maybe that was the problem. Just wondered if anyone else has had trouble with float height

Yeah I think its happened in the past from time to time, you wouldn't be the first. My float height needed adjusting too actually, but I don't think it was out enough to cause it to run funny.

[droverdave]

As far as i understand the float is responsible for the fuel pressure that the jets see.

So essentially if the float is out, the whole thing wont work properly, so yes i've no doubt it was the cause of your issues.

[Slambow]

Cool. Thanks for your insight fellas. Il know to check that if it happens again, got the extra filter on now though so hopefully not. I'm just a plumber, these carbs with anything more than a float and slide are too complicated for me!