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Bad Needle and Seat?

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2011 xc300

 

The bike was flooding on initial start up and I had a small puddle of gas under it. Figured float was hanging up or some dirt in the needle/seat. Was fine if i turned the fuel off after riding. Took it apart and cleaned everything, no signs of dirt or issues, needle is in good shape. also blew out the overflow circuit as the fuel was dumping in the intake, seems it should all flow out the overflow before running into intake?

 

Put it back together and is still doing it?

 

Was fine last year so I can't see the float height being an issue?

 

Any suggestions?

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The cavity the needle body sits in is probably corroded and needs polishing, as does the needle body\

 

...otherwise, the oring under the seat is shot, and needs to be replaced

Edited by TheKoolAidMadeMeSick

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The cavity the needle body sits in is probably corroded and needs polishing, as does the needle body\

 

...otherwise, the oring under the seat is shot, and needs to be replaced

 

Thanks. i will take it apart and have another look. Never had to remove a needle seat before, not even sure how but hopefully it will be obvious?

 

I didn't reaize there was a oring under the seat but will check that also.

 

Just watched a video where a guy polishes the seat with some metal polish and a q-tip in a drill. Looked effective.

 

Funny because I bench tested the carb after cleaning. I hooked it up to the fuel tank with no bowl on it, float up to see if it would leak and didn;t seem to. Left it for about a hlaf hour and no drips? I went for a ride then put the bike in the trailer with the fuel still on and by the time I got home, about a half hour, I had a small puddle under it? Seems odd.

 

I will report back once I have time to check it. Hopefully tonight.

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You can purchase slide hammers in multiple sizes

It takes a small amount of patience and finesse to remove the seat without damaging the carb body

It is best done with the carb body sandwiched in a wood vise

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An alternative to a specialty slide hammer is an automatic center punch. Just turn it all the way down to the softest setting.

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I polished the seat with some metal polish, a drill and a qtip. Definitely brought it up to a nice shine.

 

I have left my fuel on to see if it leaks and it does not appear to, no puddle under it. I should know for sure when I go to start it tonight.

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went for a ride then put the bike in the trailer with the fuel still on and by the time I got home, about a half hour, I had a small puddle under it? Seems odd.

I will report back once I have time to check it. Hopefully tonight.

Doesn't seem odd at all. I would expect it. Leaving the petcock on, running down the road with the carb float experiencing every bump and g out the trailer does. With every bump in the road, the float/seat experiences a momentary increase in head pressure from the fuel in the tank.

So you didn't check float height while you had it apart? Do so this next time. Yes, it should seem obvious how to remove it. Slide out the pin that the float hangs from. Lift out the float and the inlet needle comes with it, hanging from its little tab on the float.

The inlet needle doesn't have an o ring under it. Thats incorrect wording. The needle tip itself is a hard type of rubber that seals the seat. Look very carefully for a ring the size of the hole in the seat, worn into the rubber tip of the needle.

Yes, fuel should run out the overflow before running into the intake. But if its stopped up, there's no place else for it to go. Fuel would eventually try to equalize itself with the level of fuel in the tank, filling up the engine with fuel as it does so.

Always turn the petcock off after riding.

Unless the seat is corroded, pitted or damaged, it shouldn't need replacing.

Edited by Trailryder42

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Doesn't seem odd at all. I would expect it. Leaving the petcock on, running down the road with the carb float experiencing every bump and g out the trailer does. With every bump in the road, the float/seat experiences a momentary increase in head pressure from the fuel in the tank.

So you didn't check float height while you had it apart? Do so this next time. Yes, it should seem obvious how to remove it. Slide out the pin that the float hangs from. Lift out the float and the inlet needle comes with it, hanging from its little tab on the float.

The inlet needle doesn't have an o ring under it. Thats incorrect wording. The needle tip itself is a hard type of rubber that seals the seat. Look very carefully for a ring the size of the hole in the seat, worn into the rubber tip of the needle.

Yes, fuel should run out the overflow before running into the intake. But if its stopped up, there's no place else for it to go. Fuel would eventually try to equalize itself with the level of fuel in the tank, filling up the engine with fuel as it does so.

Always turn the petcock off after riding.

Unless the seat is corroded, pitted or damaged, it shouldn't need replacing.

 

I've always left my fuel on and never had a bike do this? After polishing the seat it didn't seem to though.

 

I see your point with the effects of going down the road and the increase in pressure but I would think if the needle and seat were functionong properly, with the float submerged in the fuel, even driving down the road it shouldn't allow fuel through.

 

 

I know how to remove a float it was the seat that i was wondering about removing. Hopefully I won't have to.

 

 

I inspected the needle tip and it appeared perfect through my slowly diminishing eye sight (even with reading glasses on)

 

30 years of riding and only ever turned the fuel off when putting them away for the winter to drain the bowl. Always worried I will get halfway through the first lap of a race before being reminded I forgot to turn it on :banghead:  Maybe I'll start :thumbsup:

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I left the bike sit for a while with the fuel on and it's still leaking a little :banghead:

 

I figure if I am goin to the trouble of pulling the seat to change the oring I might as well change the needle and seat?

 

Doesn't even look like KTM calls it out as a replaceable part? Anyone know where to get these parts?

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Checked out sudco, I didn't see a seat avaialbe for the carb?

 

I decided i would try to change just the needle first. With it being a rubber tip and the seat being brass I would assume the needle would be the part to wear. I see different opinions on whether or not there is an oring under the seat that can wear? None of the schematics i look at shows the seat out so I don't know for sure.

 

Checked the float height while I was in there and it was high compared to what I see guys setting it to in other threads. I dropped it a couple of mm's.

 

We'll see how that goes. Will update soon.

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thread hi jack kinda ?

hey krannie do we have this replaceable o-ring  in mikuni cv street bike carbs also? my buddys old fj1200 has been to shops but just continues to leak out the overflow tubes. I can stop 3 of the 4 from leaking by cracking the gas cap- bad venting I guess but that 4th one is going to make me pull the carbs out of the bike.

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