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Post Info TOPIC: What is the port on the lower right side of the bowl for?


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What is the port on the lower right side of the bowl for?
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I have a leak from the port at the right bottom of the bowl. Anyone know what this port is for? Is it supposed to the covered/blocked or something?

I just did a full rebuild on the carb and most of the gaskets/rings/diaphragm/etc are new. According to receipts from the previous owner a dealer replaced the float needle valve not that long ago and it does look like it's in good shape.

The leak happens when the bike is sitting not running. Either upright or on the kickstand it still continuously leaks.

 

Here is a picture of what I'm talking about. I searched all over but haven't found a description of this one.

YTyv3vf.png



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It's the overflow - there should have been a tube attached to it that runs down between the engine and swingarm.

Brian



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TTRfan wrote:

It's the overflow - there should have been a tube attached to it that runs down between the engine and swingarm.

Brian


 

I thought the overflow was above the bowl (the brass coloured one in the picture). That's currently what I have connected to the drain pipe.

Like the bowl drain, that lower port doesn't have any ribs on it. It doesn't seem like it would have a hose/pipe connected. ?

Thanks for the help!

Edit: Finally found a better diagram. OK, now I see that normally there is a hose connected to that. Mine didn't come with one. So I guess it's the bowl overflowing? Maybe the float needle actually is bad... Hmmm.

So there are 3 carb drain/vent hoses going out of the carb? What a weird design. Or maybe I have something hooked up wrong.



-- Edited by Sprok on Monday 4th of April 2016 09:04:30 PM

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It does sound like the float needle is not seating for some reason and allowing petrol to continue to seep into the float bowl cry



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Well I tried polishing the seat until it was like a mirror. Also polished the o-ring seat. Absolutely no change. It spurts a splash of fuel out the overflow about once or twice an hour. :(

There is some black "stuff" on the inside of the carb bore where the o-ring goes. I tried polishing that but couldn't get it off. Even tried (carefully) poking at it with a pick and it's really hard. I can't tell what it is but it's almost like corrosion. Not sure why the carb would be corroded, maybe just hardened o-ring. I can't get it off in any case. Steel wool or something might work (if it's not corrosion) but I can't get it in there.. not to mention the mess that would make inside the carb.

So I think it might be leaking around the seat's o-ring. I'm debating options. Currently I'm thinking of trying a fuel-resistant grease (ez turn?) to lube up the o-ring and the whole outside of the seat to maybe get it to seal with the grease. Yama/Honda/Motoseal might work but I'm afraid that would glue the seat in place and I won't be able to get it out.

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I tried sealing the exterior/o-ring of the valve seat with EZ-Turn which is an aircraft fuel-proof grease/sealant. STILL leaking a drip every 2 or 3 seconds. So it seems to be coming from the needle seal. I even tried a bit of the EZ Turn on the tip of the needle and STILL leaking! WTF?!?!

I don't get it. That set was only 6 months old, polished like a mirror, the needle looked in perfect condition, sealed with grease, and it still leaked. The screw that was holding the seat was REALLY tight. Like ridiculously tight. Maybe that warped the seat or something (seems unlikely, just grasping). Maybe the needle tip is very slightly hardened from the ethanol. Nothing on this carb seems ethanol resistant.

I ended up replacing the seat and needle and now it doesn't leak. Feels like a waste of $15, the old one should work! If it is the ethanol then this new one will probably start leaking in some months. :( I know the bowl gasket was badly eaten/pitted in only 6 months. I went through the whole carb and greased all the rubber parts with the EZ-Turn to hopefully help protect it from the ethanol. I didn't grease the needle tip though because I was afraid it might leak _because_ of the grease (it's pretty thick/sticky stuff). I guess if this new set dies in a short time I will try greasing the needle on the next one.

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Hey Sprok

how much ethanol do you have in your fuel ?

in Aus we have 10% in 91-95 octane, I literally have never turned off the fuel tap and never had a leak in the 3 years I have had the bike

always starts first time, except for last week biggrin

I wouldn't blame the carby or it's internals if mine is anything to go by, I don't think it's an ethanol issue unless you have way more in your fuel in the US

Cheers

BMSteve

 



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2004 TTR250 - Highway Dirtbike Hand Guards, 38mm Bar Risers, D606 Front & Rear, Opened up Airbox with Twin Air Filter, Re-jetted Carby, B+B Bash Plate & Frame Guards, DIY 3mm Alloy Tail Tidy, 14/47 Gearing.

 



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10% here also. You might be right. I can only go by the receipts that I have from the previous owner. Maybe the dealer didn't actually replace what they said they did or maybe the dealer or owner put something aggressive in the fuel, tank, carb. The bowl gasket was still flexible so it seemed new (should have been, according to receipts) but it was very badly dissolved/pitted. The diaphragm and o-rings were totally destroyed but I don't know their age.

I hope you're right and my new set lasts for years. :)

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The new needle is leaking again now. So what, 7 or 8 months? This is no good!

Not sure what to do. I read about some carbs having problems with the floats absorbing ethanol and/or water from the alcohol which makes them not float as strongly as they should. My floats are also new though and the float level looks good. I think it's just the needle that isn't sealing completely. My guess is the alcohol in the gas is making the rubber tip on the needle slightly hard.

I guess I could try yet another needle with the grease on it to see if that protects from the alcohol. I'd also like to find some alcohol resistant floats just so I can rule that out. Maybe a stronger spring on the needle? That might be tricky to tune.

Or I wonder how hard it would be to make my own rubber tip for the needle... Or maybe use a newer design needle from a different bike/carb that is built to be more alcohol resistant. Hmmm...

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I have tried it multiple times seeing if anything would seal but no luck. I think this is failure in the worst way.

I'm looking for a new carb. What's the best replacement for this old-school leaky piece of goodness? Something that can handle ethanol bullcrap.

 

Anyone else wonder if this is the worst possible place to post questions about anything? Yeah, I'm going to try anywhere else. You might do OK dude, but not in my life.



-- Edited by Sprok on Wednesday 14th of December 2016 12:11:23 AM

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Sorry Sprok but I have no experience of the evil rubber eating ethanol fuel you write about. Also. I have not heard of this problem on the forum before that I can recall (and I am sure you have thoroughly searched for information) so have no experience to draw on or remedy to suggest disbelief

I am sure that if there was another owner reading your thread that knew the answer(s) they would have volunteered a solution by now so please don't be too harsh on us!

I have run the standard TTR carb on the many TTRs that I have owned and rebuilt and have not come across your problem before. The usual problem owners find is that fuel left standing in the TTR's carb blocks the pilot jet - something that I am sure could happen to any carbed bike.

Brian



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Don't infect this forum with your unpleasant comments! Sorry we can't think of a solution to your problem. Strongly suggest you look elsewhere, dude.

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Infect? lol... This is *the* place to go for TTR info. "TTRfan" is an awesome guy but he is just one guy, he can't be expected to hold up the whole community and lets face it, outside of him, what little "community" there is are really just idiots like me. I appreciate what he has done more than I can express here!

Probably general forums on motors are more useful when dealing with this particular problem. Sorry I asked here (really sorry, I was drunk and not thinking).

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Sprok wrote:

I have tried it multiple times seeing if anything would seal but no luck. I think this is failure in the worst way.

I'm looking for a new carb. What's the best replacement for this old-school leaky piece of goodness? Something that can handle ethanol bullcrap.

 

Anyone else wonder if this is the worst possible place to post questions about anything? Yeah, I'm going to try anywhere else. You might do OK dude, but not in my life.



-- Edited by Sprok on Wednesday 14th of December 2016 12:11:23 AM


Not very nice to readcry Maybe don't post when you are drunk? 



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"Anyone else wonder if this is the worst possible place to post questions about anything? Yeah, I'm going to try anywhere else. You might do OK dude, but not in my life."

I found this offensive.

" Sorry I asked here (really sorry, I was drunk and not thinking). "

And this.

You were right to ask here, someone might have known the answer. The fact that noone did does not make us all idiots thanks. What makes you think anyone on a general forum is any brighter than here? Sometimes going to an actual workshop and communicating face to face with a professional is best, rather than spending 8 months pontificating.

Anyway, till trying to work out why you've got the leak, and rereading one of the posts...

"The screw that was holding the seat was REALLY tight. Like ridiculously tight. "

Maybe so tight it cracked the alloy of the carb body? Since there are plenty of others on here from states using high ethanol content fuel, and none have had this problem, it seems odd to blame the ethanol?

Good luck.

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