GS650L carbs.

[fredintoon]

I'm helping someone get his newly acquired GS650L running again after he crashed it last fall. Only had to double-clean the carbs to get the engine running. Some things puzzle me though. 1) There's a connector tee between #1 & #2 carbs and another between #3 & #4. Not gasoline feeds, there's only one of those, these tees are higher up the carb bodies and appear to be some kind of breather? Anyhow, the two open connectors each have rubber hose pushed over them and the hoses are joined together by plastic barbed connector into a loop that just joins the two carb pairs. So is this a thing the PO has done (he'd also put the vacuum operated fuel tap together backwards!) or is it supposed to be like that or what?
2) The fuel gauge sensor on the gas tank has 2 wires, fine, understandable. It also has a hose connector. There's no hose on it although it's end is bright & shiny like there was one there once. Whatever is that hose connection for?

[Ken Talbot]

This sounds like the float bowl vents on the early model carbs on the XS11. On an XS, the upper "T"s are plumbed to a couple of nipples on the upper half of the airbox which allows tham to vent, and keeps bugs and dirt out of the vent lines. If you connect the two "T"s together, the bowls do not vent properly and you get fuel delivery problems.

[TopCatGr58]

Hey Fred,

Have you tried putting a hose on the gas tank connector and applying suction? If it's just free flowing, it might be a drain for the gas cap area like on the standards??? Otherwise, don't have a clue?
T.C.

[prometheus578]

"Like everyone said"

The first is for float bowl venting... as the fuel level rises, the air must be displaced somewhere. If the lines are plugged, the air won't be displaced, changing the atmospheric pressure in the bowl... the float won't rise properly, and the carbs will overflow.
The second, as stated, is for an overflow/vent line. Not really for moisture, but the ones that I've seen, mostly Kawa, it's a plastic housing that covers the fuel indicator setup. If the gasket around it ever fails, the fuel drips into the cover, and via the hose, get's routed away from important stuff.

[fredintoon]

"If you connect the two "T"s together, the bowls do not vent properly and you get fuel delivery problems."
Hi Ken,
yes, that makes sense. But on this bike there's nowhere to put the other ends onto. The airbox has a fat hose at the top that goes to the engine breather and a skinny hose underneath that drains onto the street. And nothing else. If the barb joining those two (~12") long hoses is removed there's nowhere for them to go.
Should they have little filters on them? Be left hanging loose?

[AlanB]

Hi Fred,

Get a book for it, or find a fiche on the 'net; perhaps try asking on a Suzuki forum? (LOL!) The best plan would be to find out where they are meant to go..... and do that!

My bowl vents have hung loose for a decade with no ill effects; as far as I can figure out, there is no real "flow" through 'em, they are to eliminate pressure differences. Filters are mainly to keep insects out...... I guess you have about as much problem with that as I do?....LOL

AlanB

[fredintoon]

final note

Thanks to all who responded. The GS650L is now up and running and not cluttering up my garage. The owner rode away happy last month after he found a "Bro with hydraulic press" to straighten his fork tubes so the front wheel once again pointed the same way as the 'bars.
He decided to just leave those mystery hoses off and that seemed to be working.
I told him "Put plates on that bike before you ride it" but would he listen? Yeah, right. He must have golden horseshoes up his arse, the cop who pulled in behind him at the gas station only made him have the bike towed home rather than writing him a ticket.

[egsols]

Fred,

I just helped a friend with his Kawi KLR650. His carb vent hose was melted by the exhaust resulting in the hose being restricted.

The bike is a 2007 and the stock config is to just let the vent hose dangle to the bottom of the bike.

Could be the same set up on the GS, just need longer hoses to vent out to the bottom and prevent any dirt from getting in.