GT380 fuel problem

[Organicjedi]

My buddy's GT380 is showing signs of a fuel issue. It's dropping some gas, cold blooded, and has quit on him when riding. Seems like it's flooding somewhere.

He's suspecting an issue with the vaccum petcock and is considering a mod that just makes it flow. I'm wondering if its a stuck needle or another carb issue.

Any ideas on what to check? I'm not familiar with these.

[Old Brit]

Check with the Guys that use this UK forum http://www.kettleclinic.co.uk/kcforum/viewforum.php?f=2 where there's a section for the smaller Suzy triples, I'm sure they'll be happy to help 👍

[Barrie]

It's a float needle problem, check float heights and the valve themselves, nothing to do with the vac tap.
See if you can replace the float valve assemblies for a equivalent with viton tips.

[m in sc]

I'd go full manual petcock if he can

[1976RD400C]

I suppose if the vacuum petcock has some sort of a rupture it could leak or suck raw fuel down the vacuum hose to the motor.

[quocle603]

I believe a lot of the tapped threads are the same for suzuki and can use a lot of petcocks as an option. Vaccum petcocks are a pia at times

[Barrie]

Your all just frightened by things you don't understand and can't work out how to test.

[Jspooner]

Your all just frightened by things you don't understand and can't work out how to test.

PM sent

[m in sc]

the o ring can get old and seep, or the diaphragm can warp and/or leak. either way, sucking fuel through the diaphragm IS possible, but usually has more to do with the plunger o-ring not sealing. the downside is it can cause the carbs to over flow, or worse, allow it to seep into the motor and hydrolock.  Been there, seen it, done it.  On my concours (the only bike i currently have with a vacuum petock, the rest were changed to manual ones) I have an inline valve as well to cut off when i park it. The vacuum petock does work fine, but they DO go over time. Especially with modern fuels.   

[Jspooner]

I worked on a GT250 with the same problem. Found a manual petcock on eBay and problem solved. Couldn't find one with the exact bolt spacing but it was close enough that all I had to do was open the holes up a couple of sizes and it worked.

[Organicjedi]

I worked on a GT250 with the same problem. Found a manual petcock on eBay and problem solved. Couldn't find one with the exact bolt spacing but it was close enough that all I had to do was open the holes up a couple of sizes and it worked.

Any idea which petcock you bought?

[Jspooner]

I'll find it and send you the link.

[Old Brit]

Your all just frightened by things you don't understand and can't work out how to test.

Life would be so simple, if maybe a tad boring, if the rest of us were as smart as you 

[Organicjedi]

He's going to try to either mod the current petcock or get a gravity fed one that fits. Thanks for the suggestions.