They keep leaking ...and leaking ...and leaking

[cywelchjr]

I recall trimming the new bowl gaskets when I installed them. I DIDN'T do the bowl tap test to try and stop the fuel the last time because I was about at my witts end with the leaking and the right thing to do sometimes escapes us at that point.

3Phase... you scare me. I've got the mist at all RPM's and seem to have a sticky throttle because a slight blip on the bars results in a half second burst in RPM's. At first I thought weak tension on a throttle return spring, but I watched it and it appeared to be working properly. Would that be an excess fuel symptom?

Almost wondering if it'd be easier to just take it to the yammy shop and have them tinker @ $60/hr. and have it all synched up and what have you. OIE!

Generally the RPM's hanging up a bit is a sign of the mixture being a bit too lean. You might need to richen the mixture out just a little. But the misting may be valves too tight. Did you check the valve adjustment to make sure they are adjusted properly?

[3Phase]

Sorry, man, didn't mean to scare you!

[CaptonZap]

The misting could also be normal stand off. The stock arrangement had velocity tubes, which contained the stand off. Without pods or the tubes, you may see a jaw breaker size ball of mist hanging in front of the carb mouth. It is a result of cam overlap, but usually is only noticable under load at large throttle openings. Have you done a leakdown compression test? Listen for hissing from the carbs. A leaking intake valve will produce the same effect. CZ

[petejw]

the fuel misting could also be the intake valve
not sealing properly when its closed,
valve lapping would fix this.

[Jefe]

floats that don't - fixable or no?

Thanks for the tips, folks - it's helped my diagnosis.

The patient is a basked case 1980SG getting a 79SF engine transplant.

I cleaned the basket carbs and the engine fired first time I cranked it. Then, realizing carbs were leaking gas, I shut it down for the next day, figuring it the new fuel line clamps were loose. I left the petcocks on, and next day the start was slow, the gas was low and I felt the heartbreak of gas-flavored oil.

Following natemoen's advice, I dunked the plastic floats in hot water and found two leakers. I was thinking of dabbing some epoxy on the spot, but worry I might screw them up by making them float lower in the fuel.

Any recommendations on how to repair them or get a line on floats with integrity?

Thanks amigos,

Jeff

[natemoen]

Thanks for the tips, folks - it's helped my diagnosis.

The patient is a basked case 1980SG getting a 79SF engine transplant.

I cleaned the basket carbs and the engine fired first time I cranked it. Then, realizing carbs were leaking gas, I shut it down for the next day, figuring it the new fuel line clamps were loose. I left the petcocks on, and next day the start was slow, the gas was low and I felt the heartbreak of gas-flavored oil.

Following natemoen's advice, I dunked the plastic floats in hot water and found two leakers. I was thinking of dabbing some epoxy on the spot, but worry I might screw them up by making them float lower in the fuel.

Any recommendations on how to repair them or get a line on floats with integrity?

Thanks amigos,

Jeff

Easy, not so cheap (but not to bad) method, buy the plastic floats from the later model carbs.

Very hard, time consuming and cheap method, resolder them. Really hard to do this because you need to keep them balanced and floating the same across all 8 (2 on each float) floats. Is it doable.....yes, very very difficult.

[bikerphil]

Following natemoen's advice, I dunked the plastic floats in hot water and found two leakers. I was thinking of dabbing some epoxy on the spot, but worry I might screw them up by making them float lower in the fuel.

Any recommendations on how to repair them or get a line on floats with integrity?

New plastic floats, $19 a pop, scroll down....

http://www.partsnmore.com/parts/yamaha/xs1100/?filters[fitting]=custom

[SFerinTEXAS]

I dunked the plastic floats in hot water and found two leakers

Can no one speak to this? Been spouting off to much lately so its not gonna be me.

[Rasputin]

Yes I can! If you found two leakers in plastic floats the you have done something really incredible my friend. Brass maybe!

[natemoen]

I missed the plastic part. Aren't the plastic ones a solid foam material?

[Jefe]

thanks, amigos

Thanks, natemoen for warning me off trying to fix the floats.

Since bikerphil linked to new ones for $13 apiece, that seemed the right move and they're on order.

Jeff
79 XS1100F - electrocuted by a short
80 XS1100G - engine transplant with ongoing complications
83 CX650 - still a basket
81 KZ305 - wimpy but game
84 V30 Magna - hmm

[Jefe]

foam leakers?

If those plastic ones are foam, why would they ooze out bubbles like a boiling egg? However, that helps explain why I couldn't hear anything shaking around in there!

However, I know they're bad now, because I learned 'em both with shiny coats of epoxy ...

Jeff

[somesuch]

Easy, not so cheap (but not to bad) method, buy the plastic floats from the later model carbs.

Very hard, time consuming and cheap method, resolder them. Really hard to do this because you need to keep them balanced and floating the same across all 8 (2 on each float) floats. Is it doable.....yes, very very difficult.

I think that this is the best solution. Those black floats will never need attention again!

--Nick

[oldyam80sg]

I would be very hesitant to take it to a shop to have work done unless those guys know these bikes.I get all my info here and last time took it to a shop they wouldn't even touch it!

[BlindogSmokin]

fuel leak

Did you polish the needle seats as recommended?
I discovered this little tip while doing an XS650.

When brass corrodes it leave a rough texture to the surface. The needles drag on it and can cause intermitent fuel leakage. Polishing the brass makes it slick again, eliminating drag.

I had a similar issue but after polishing the seats with a Q-tip, and auto rubbing compound they shined up like a new penny. One had a very small nick in it, which I couldnt see until it was polished, so I replaced it, with one from a spare carb. The problem went away. Also the springs in the needle valve have to work, no sticking. If they stick you might get them altogether and the first time the float depresses it, if it sticks, it will throw off the float adjustment and leak. On one seat I had there was a small bur at the top where a PO had hammered on them. I used a pocket knife and slightly beveled it at the top where the needle slides in and removed the bur.

In someways I am thankful that the PO screwed the carbs up so bad they couldnt get it to run anymore. It was probably the only factor that kept them from completely destroying the bike beyond repair.

Bench tested like I was told and everything checked out good. I put the bastards on the bike and I STILL have fuel leaking from the back of the carbs... So instantly I'm POed .

I continue to hook up the throttle cable and tighten the carb boot clamps and even put the clutch cable through that little keeper on #4.

I crank it... just cranks, fuel still leaking

I crank it w/the choke out one "notch"... just cranks, fuel still leaking

I crank it w/full choke... SHE FIRES!! Fuel leak stops.

I now cannot get the fuel to leak, but am worried it will come back to haunt me. Should I be worried?

I'm also getting a fuel/air mist from #4 carb only and a slight popping from the exhaust. I tried leaning it up a bit and managed to decrease the popping, but maintained the mist.

Thank you so much to everyone of you guys (ladies included) for helping me out so much on my never ending venture to restoration of not just 1 but 2 bikes.