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Gas breather cap

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Interesting story this weekend at Tahuya. Pulled the bike out of the truck, turned the fuel on , threw a leg over the bike and fired it up after a couple kicks. Warmed up and hit the trails. About 30 minutes into the ride I started noticing my bike was leaning out. (CRF 250X). Lots of backfiring and power was down. I didn’t really pay much attention to up because the conditions were so bad, (wet, slippery, snow, cold, etc) and just kept plugging away. I felt as throw I was working real hard to keep up with the guys up front, well harder than normal I guess. Anyway now my bike dies and won’t start. Sit there for a few minutes, luckily I have the magic button, but regardless it will not start. I don’t want to completely drain my battery so I started kicking it. Nothing. Then one more kick and it starts and seems to be running fine. My first thought was maybe I got some water in my gas. Well this problem plagued me for the last 10 miles before lunch. It dies about 4 times. I would hear and feel it lean out then die. Won’t start for 5 minutes then suddenly fires right up.

So back at the staging area my first thought was to drain the carb and tank and put fresh fuel in it. I pull off the fuel line to drain the tank and no fuel comes out. Oh, I must be out fuel, but we had only rode 30 miles at that point. I open the gas cap and suddenly fuel starts spewing out of the fuel line I had already removed. So it turns out there was a vacuum in my tank because the breather cap was plugged. I have always heard you need to check those and clean them regularly but never got around to doing it.

So the moral of this story is that anyone who runs those little gas cap breathers should check and clean them often. Mine was about 8 months old but with the amount of dirty water and mud we ride through at Tahuya they will get plugged.

Thomas

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Interesting story this weekend at Tahuya. Pulled the bike out of the truck, turned the fuel on , threw a leg over the bike and fired it up after a couple kicks. Warmed up and hit the trails. About 30 minutes into the ride I started noticing my bike was leaning out. (CRF 250X). Lots of backfiring and power was down. I didn’t really pay much attention to up because the conditions were so bad, (wet, slippery, snow, cold, etc) and just kept plugging away. I felt as throw I was working real hard to keep up with the guys up front, well harder than normal I guess. Anyway now my bike dies and won’t start. Sit there for a few minutes, luckily I have the magic button, but regardless it will not start. I don’t want to completely drain my battery so I started kicking it. Nothing. Then one more kick and it starts and seems to be running fine. My first thought was maybe I got some water in my gas. Well this problem plagued me for the last 10 miles before lunch. It dies about 4 times. I would hear and feel it lean out then die. Won’t start for 5 minutes then suddenly fires right up.

So back at the staging area my first thought was to drain the carb and tank and put fresh fuel in it. I pull off the fuel line to drain the tank and no fuel comes out. Oh, I must be out fuel, but we had only rode 30 miles at that point. I open the gas cap and suddenly fuel starts spewing out of the fuel line I had already removed. So it turns out there was a vacuum in my tank because the breather cap was plugged. I have always heard you need to check those and clean them regularly but never got around to doing it.

So the moral of this story is that anyone who runs those little gas cap breathers should check and clean them often. Mine was about 8 months old but with the amount of dirty water and mud we ride through at Tahuya they will get plugged.

Thomas

I'm surprised you had one stay on for 8 months. I lost so many of those that I just went back to the tried and true hose up to the forks.

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I'm surprised you had one stay on for 8 months. I lost so many of those that just went back to the tried and true hose up to the forks.

That is all I ever run. I have heard many stories on those little stubbies plugging up. Never have an issue with a full vent hose to the front forks!

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I think some brands may be better than others. I had one that I could not use in the summertime when things got hot. Lost it and replaced with another one by well known manufacturer and never have had the same issue.

TONY

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I also prefer the long vent tube as well...that way when gassing up, can't loose your gas cap when it is handing right there for ya

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I also prefer the long vent tube as well...that way when gassing up, can't loose your gas cap when it is handing right there for ya

If the hose is long enough to go all the way to the bottom of the triple clamp, cut the hose end at an angle. Otherwise it is possible for the flat end to sit on the flat surface, then the tiny suction from the fuel flowing out of the tank will stop the vent from working.

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If the hose is long enough to go all the way to the bottom of the triple clamp, cut the hose end at an angle. Otherwise it is possible for the flat end to sit on the flat surface, then the tiny suction from the fuel flowing out of the tank will stop the vent from working.

True...but KTMs have a 90 degree plastic fitting the vent tube connects to on the steering head. That in turns drains to inside the front frame cradle and out the bottom.

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That is all I ever run. I have heard many stories on those little stubbies plugging up. Never have an issue with a full vent hose to the front forks!

YEP, me too.....i have always heard not to run those due to this very issue.

Joe

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I can't keep the stubbies on. They always fall off for me. I just use this:

fre_07_150505.jpg

Nice one way valve to keep the gas in and the air flowing towards the tank as it gets down in volume. The double bonus is that it won't come off despite getting up on the tank.:) It's old-skool but it works!

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I use one of those shurb. There are complaints with those not venting properly and the fuel boiling in the tank on big KTM's. Mostly in summer heat. It's handy for washing the bike on it's side.

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Having lost two of those vent cap stubby things, it's back to the hose for good. Never kept one long enough for it to get clogged up. Just a bad idea from the get go. A billet gas cap is enough bling for me.

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Interesting story this weekend at Tahuya. Pulled the bike out of the truck, turned the fuel on , threw a leg over the bike and fired it up after a couple kicks. Warmed up and hit the trails. About 30 minutes into the ride I started noticing my bike was leaning out. (CRF 250X). Lots of backfiring and power was down. I didn’t really pay much attention to up because the conditions were so bad, (wet, slippery, snow, cold, etc) and just kept plugging away. I felt as throw I was working real hard to keep up with the guys up front, well harder than normal I guess. Anyway now my bike dies and won’t start. Sit there for a few minutes, luckily I have the magic button, but regardless it will not start. I don’t want to completely drain my battery so I started kicking it. Nothing. Then one more kick and it starts and seems to be running fine. My first thought was maybe I got some water in my gas. Well this problem plagued me for the last 10 miles before lunch. It dies about 4 times. I would hear and feel it lean out then die. Won’t start for 5 minutes then suddenly fires right up.

So back at the staging area my first thought was to drain the carb and tank and put fresh fuel in it. I pull off the fuel line to drain the tank and no fuel comes out. Oh, I must be out fuel, but we had only rode 30 miles at that point. I open the gas cap and suddenly fuel starts spewing out of the fuel line I had already removed. So it turns out there was a vacuum in my tank because the breather cap was plugged. I have always heard you need to check those and clean them regularly but never got around to doing it.

So the moral of this story is that anyone who runs those little gas cap breathers should check and clean them often. Mine was about 8 months old but with the amount of dirty water and mud we ride through at Tahuya they will get plugged.

Thomas

Hey Thomas, I'm glad you got that sorted out at the truck so you and Brent could continue with us on our 75 mile beat down ride in those miserable conditions.

Nothing like mobbin through Tahuya single track in a endless downpour for enduro conditioning. I'm gettin cold again just thinking about it.

I'll be in touch,

Roscoe

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Thanks for the GREAT BEAT DOWN Roscoe. :banghead: I had great ride, my fore arms should recover for round two this weekend and then the enduro.:banghead: Hope too ride with you guys again soon.:)

Brent

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