Intermittent carb leak

[Krohsis]

I have a leak from the carb that occurs only occasionally. Actually this is the second time it has happened, and I have ridden the bike several times in between. The carb is leaking through this orifice that is circled. If it leaks it leaks for a short time then stops.

The shop manual doesn't say what this orifice is for.

Can you shed some light on this for me and what would cause an intermittent leak.

Thanks.

 

[Fire-medic]

https://dn790009.ca.archive.org/0/i...ice-manual/yamahavmaxvmx12-service-manual.pdf

#3, main air jet?

 

[Krohsis]

Thanks Fire, that has to be it as the other spots on that part of the carb are blocked . But I don't understand why gas would back up through that spot unless it is an intermittent float needle sticking open. The diagram isn't clear enough to see if the float bowl has access to that spot to vent there rather than the overflow tube that drains under the bike.

Also the occasional leak is weird and I have watched it leak at start up, but shortly it stops.

Very strange. And it doesn't help I've never worked on carbs in that configuration, just the style where the throat is parallel with the ground, not perpendicular like these.

If anyone has bright ideas, lay it on me. Maybe Sean will chip in.

 

[MaxMidnight]

Is it just the one carb and when it is 'performing' and how does it effect the running?
When you are riding the bike how does it perform; any hesitations or misfire on acceleration, cruise or overrun?

Unless you have have an issue that is affecting the running of the bike why is it a problem?
The danger is that you spend a disproportionate amount of time trying to fix something that may be normal but as it isn't normally visible.

 

[dannymax]

Think you're correct with the intermittent sticking float/needle.

 

[Krohsis]

Is it just the one carb and when it is 'performing' and how does it effect the running?
When you are riding the bike how does it perform; any hesitations or misfire on acceleration, cruise or overrun?

Unless you have have an issue that is affecting the running of the bike why is it a problem?
The danger is that you spend a disproportionate amount of time trying to fix something that may be normal but as it isn't normally visible.

Because it spills gas out on the motor, quite a bit. If it does it hot the chance of a fire is high. Performance is fine, runs strong and clean, idles smooth.

 

[Gbianchi]

What dannymax says, been there done that every spring needle is sticky, cleaned mine and good to go will be replacing this year.

 

[Gbianchi]

SO today I got after that over flowing carb, did not start out very well, first I started the bike to see if it still leaked, well NO it doesn't. Why not? OH it's because my fuel pump is not working, WHY? Gurrr. Well I have been running with the switch in RES since owning it, hot wired the pump yay it works, I hosed down the switch pod with Wd40 and worked it over several times, yay pump is working! Now that carb is overflowing nicely, dang. I didn't want to remove the carbs AGAIN, so I disconnected that fuel line a hosed down the input with the drain screw open, then gave it a shot of compressed air, yay no more overflow, shut down to reassemble, thought oh just one more check, bike won't start, battery low, PC680, never a hint of trouble, Gurrr! Got it to start check voltage, 12.1. GURRR! Recently replaced rectifier but didn't remove charging wire connector, will definitely be doing that next. I think these bikes are getting old, and need some help? Okay so that is my Vmax day.