Carburettor Leaking On New Bike

[Lickey]

I really dont think flaming will get you anywhere, so admit defeat!! and slap my thigh,, bye bye!

[edwinchester]

Lets have a vote and decide the 'winner'.

I agree with Thanh. Some maybe even all Mikunis have an overflow tube. That was all he was saying and in my opinion has been proved.

[LivinLOS]

Thanh winner by a country mile..

Lickey lost that one in early round. He just doesnt seem to know hes lost.

[PeaceBlondie]

Sorry to interrupt with a serious comment on this comedy thread, but Thanh and Lickey need to quit their fighting, and I advise they not even try to go to PM.

[apetley]

Yeah Thanh the man!

He can fix my overflow any day.

[Lickey]

Float bowl drain tube yes, overflow tube, never!!!, no Mikuni or other carbs have this, go on somebody, prove me wrong!

Ok Ok, I suppose its time to come clean, above is my original post and im sticking by it! the tube in question is an atmospheric tube, it allows the air in the float chamber to be equal to outside air,

Thats what it is there for. and if fuel comes out of this, belive it or not could be due to a worn side stand pivot,allowing the bike to lean over to far,or a sticking/worn float valve needle,blocked vent hole in the fuel tank forcing fuel into the carb/s, and various other reasons.

If somebody would have asked me "what is this tube for then?" i would have explained, its not my nature to be agressive, but a certain party was, my coments where without flaming, and always will be.

Do a web search on Mikuni atmospheric tubes, if you still have doubts.

Dont worry PB, im very sure there will be no PMs .

Geoff, hows the new bike going, all to your satisfaction i hope,,,

Thanks all, Lickey.

[Thanh-BKK]

My dear friend Lickey.

You may now call it "Ahmospheric Tube", "Weird Piece Of Brass Pipe" or "John Smith", it doesn't matter - as Mikuni THEMSELVES call it ........

OVERFLOW TUBE.

Grab the Mikuni Tuning Manual from the following link:

www.nightrider.com/biketech/download/Mikuni_manuals/tune_mikuni_carbs.pdf

And have a read. I know you probably will ignore this just like the other link i provided, for you KNOW that you can't win what you lost ages ago...... so i copy/pasted the relevant bit for you, under section "Troubleshooting":

OVERFLOW: Fuel runs out of carburetor through

overflow tube on bottom of float bowl, from vent

fitting on side of carburetor or from body/float bowl

junction.

Otherwise do a web search on "Mikuni overflow tube" just like i did on "Mikuni atmospheric tube" (a term that only comes up TOGETHER with "overflow" as in *some* cases (multiple carbs interconnected) this tube provides BOTH functions while in MOST it is an overflow only!)

If this was a Formula One race, i would have lapped you twice and taken the chequered flag while you ran out of fuel in your second last lap, still you would claim victory by first saying "No car can win at all", then "only genuine cars may win and yours is fake" and now "that isn't the finish line but just some white marking on the road".

I am hereby closing this discussion for it has become pointless - fact is Mikuni carbs DO have overflow tubes, some at least do (and photographic evidence has been provided) and i DID prove you wrong (your initial challenge), so hand me that champagne and i promise not to splash water on you when i lap you next race

@ the OP:

While searching for answers to Lickey's challenge i even found a possible solution to your problem (as well as mine with the old carb):

Re: Mikuni Carb Trouble

My Mikuni 22mm was doing basically the same thing but it was running well, just spitting out lots of gas. I adjusted the float and it helped some but didn't solve it completely. I took the float out and put the needle in and gently pushed it up with my finger and it totally sealed. I looked at the float and there is a small "tab" that stops the float from going up past a certain point and it was stopping the float before it had a chance to get the needle all the way up. I bent the tab and now the float drives the needle all the way up into the seat and it stops the gas flow.

If the Gusto guys can't get it solved, you may try this yourself, after all carbs are not rocket engines

With best regards......

Thanh

[Thanh-BKK]

And just a little remark.....

I'm not flaming anyone or act aggressive even tough i had all the reasons to do so. A challenge was offered, i took it, i won it by miles. And now i'm accused of using fake evidence ("Photoshop") or being owner of fake material to begin with ("Chinese Mikuni") etc. while the challenger comes up with excuse after excuse (and ZERO evidence even after it has been asked for) in order not to admit defeat.

I'm a racer and i tend to win - or lose in dignity.

Oh, and i'm a certified motor mechanic on top of it all, i have been handling carbs for a few years (17) and seen a number of them, with and without said device, while the challenger probably never had his bike's carbs open in first place.

Best regards.....

Thanh

[edwinchester]

Hahaha

Game set and match.

Now about that Rusty Gumbo.

How about a poll on how long before the next blowup?

[HDRIDER]

Mr. Thanh

You are the winner

[geoffphuket]

Float bowl drain tube yes, overflow tube, never!!!, no Mikuni or other carbs have this, go on somebody, prove me wrong!

Ok Ok, I suppose its time to come clean, above is my original post and im sticking by it! the tube in question is an atmospheric tube, it allows the air in the float chamber to be equal to outside air,

Thats what it is there for. and if fuel comes out of this, belive it or not could be due to a worn side stand pivot,allowing the bike to lean over to far,or a sticking/worn float valve needle,blocked vent hole in the fuel tank forcing fuel into the carb/s, and various other reasons.

If somebody would have asked me "what is this tube for then?" i would have explained, its not my nature to be agressive, but a certain party was, my coments where without flaming, and always will be.

Do a web search on Mikuni atmospheric tubes, if you still have doubts.

Dont worry PB, im very sure there will be no PMs .

Geoff, hows the new bike going, all to your satisfaction i hope,,,

Thanks all, Lickey.

Replacement bike's fine thanks.....I'll not temp fate and say more, it's early days yet

Just to add my bit to the argument that's going on; the replacement bike has the two atmospheric/drain tubes (whatever)one from each carburettor connected together with a 'T' piece. A single tube then runs the length of the bike, above the level of the fuel tank and ends near the filler cap - which would indeed suggest to me that it's some sort of breather or air inlet, rather than a drain/overflow. This was all missing on the original bike, probably because someone had obviously dropped the carburettor on the assembly line, snapping the nipple off - and then had no way of completing the job properly.

geoffphuket

[Thanh-BKK]

Hi

Do your carbs have a screw on the bottom of the float bowl to drain the float bowl (like in case water got into it)? If so, the arrangement with the drain/breather hose going UP (higher than the carb) is a rather dangerous setup. Why? Because, as you have experienced already, the tube serves a dual purpose (as i correctly mentioned - it does so in some case of inter-connected multiple carbs) yet it still serves as an overflow.

HOWEVER if the connected hoses go all the way to the tank cap, that means in case your floater hangs the petrol will go right into the cylinder, hopelessly flooding the engine. In your case (four stroke) if this happens while the bike is parked, you can damage the connecting rod (or break your ankle) trying to kickstart an engine where one cylinder is full of petrol (uncompressable liquid!)

I have seen connecting rods that had a "liquid hit" (for lack of how that's called in proper English), they are bent like bananas.

Best regards.....

Thanh

[Lickey]

Float bowl drain tube yes, overflow tube, never!!!, no Mikuni or other carbs have this, go on somebody, prove me wrong!

Ok Ok, I suppose its time to come clean, above is my original post and im sticking by it! the tube in question is an atmospheric tube, it allows the air in the float chamber to be equal to outside air,

Thats what it is there for. and if fuel comes out of this, belive it or not could be due to a worn side stand pivot,allowing the bike to lean over to far,or a sticking/worn float valve needle,blocked vent hole in the fuel tank forcing fuel into the carb/s, and various other reasons.

If somebody would have asked me "what is this tube for then?" i would have explained, its not my nature to be agressive, but a certain party was, my coments where without flaming, and always will be.

Do a web search on Mikuni atmospheric tubes, if you still have doubts.

Dont worry PB, im very sure there will be no PMs .

Geoff, hows the new bike going, all to your satisfaction i hope,,,

Thanks all, Lickey.

Replacement bike's fine thanks.....I'll not temp fate and say more, it's early days yet

Just to add my bit to the argument that's going on; the replacement bike has the two atmospheric/drain tubes (whatever)one from each carburettor connected together with a 'T' piece. A single tube then runs the length of the bike, above the level of the fuel tank and ends near the filler cap - which would indeed suggest to me that it's some sort of breather or air inlet, rather than a drain/overflow. This was all missing on the original bike, probably because someone had obviously dropped the carburettor on the assembly line, snapping the nipple off - and then had no way of completing the job properly.

geoffphuket

Hi Geoff, thanks for your detailed reply, it also seems a good idea that this tube goes up to the filler cap, it will breathe in vapour rather than road crap ect, although suction is minimal even at full throttle.

If your bike came with a service and maintance book, [in english] it could suggest pulling of these tubes and undoing the grubscrew to drain the carbs, from your 1st post pic, looking at the castings, im pretty sure they have a drain facillity.

Happy and safe riding Geoff, Lickey.

[Lickey]

Thanh,

The english word you are looking for is HYDRAULIKED, which means the cylinder was part full of coolant or fuel, causing the con-rod to bent/twist/break ect.

Or you can get HYDRAULIKING, coolant leaks into the cylinder while engine is running, it sounds a bit like a cold diesel engine starting, excess fuel and diesel knock!

The worst destruction of a big diesel engine in my 40 years in diesel/petrol engineering was a V12 dorman generator engine, 1600hp, 1200kva, on a mains failiure system these engines start up on full power and full load, regardless of 1 cylinder being full of coolant, it eventually shut down by itself, after 3 months work and 50,000 pounds, it was running again.

Lickey.

[LivinLOS]

Is that the same as what americans call 'vapor lock' ??

I have always wondered what the hel_l that was..

[PeaceBlondie]

Is that the same as what americans call 'vapor lock' ??

I have always wondered what the hel_l that was..

Vapor lock would be a gas, not a liquid. They are talking about fluids such as oil or water filling the cylinder and causing a hydraulic lock. But I think the non-native speakers are arguing in English without knowing for sure what is being discussed.

geoff, we can put this dog to sleep at the request of the original poster.

...On second thought, geoffphuket has resolved his OP by having the dealer give him an entirely new example. Topic closed. There is already another Gusto Rumba thread going on.