Venting fuel tank

rampage18

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Thread starter #1
Hey guys this is my first post.

I have a question, my XT will run nice and strong until the motor has ran for about 10 min or so at higher rpm. After a while it will start to break up and if I let out of the throttle it will catch it self. I can start to run at W.O.T again. Then it will cough and break up again and then quit. It will not restart unless I push the primer again, will start and quit. Am I needing to vent my fuel system? I'm thinking I'm creating to much of a vacuum in the tank.

Any input will be appreciated, and tips and tricks are welcome also.
 

G-Man

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#2
Hey guys this is my first post.

I have a question, my XT will run nice and strong until the motor has ran for about 10 min or so at higher rpm. After a while it will start to break up and if I let out of the throttle it will catch it self. I can start to run at W.O.T again. Then it will cough and break up again and then quit. It will not restart unless I push the primer again, will start and quit. Am I needing to vent my fuel system? I'm thinking I'm creating to much of a vacuum in the tank.

Any input will be appreciated, and tips and tricks are welcome also.
Make a simple gas cap vent like this out of a nipple threaded into the cap with a short piece of fuel hose and a dirtbike tank vent valve on the end. Then cut the stock rubber seal in the cap so it is just a washer kinda like a garden hose. Boom you are done. No more bogging at half tank and hard starts below half tank. Hope this helps!! 20170403_064647.jpg
 

G-Man

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#4
oh ok that works, what if the truck rolls is it an anti syphon? or does gas come out
Gas will come out of the vent if it is on it's lid for a length of time as will your stock cap. The leakage is very minimal if at all normally. I have a tendency to be in a hurry to flip it back over. I make a point to clean out the valve on the end of the hose with carb cleaner frequently and be sure it rattles letting you know the valve is free
 

G-Man

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#5
20180302_212014.jpg Recently made a vent cap with an aluminum cap. Looks better, same function
 

pfrederi1

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#7
View attachment 14117 Recently made a vent cap with an aluminum cap. Looks better, same function
Hello GMan Thx for the post.
When you say to cut the rubber seal in the gas cap are you referring to the one that looks like a bulb under the gas cap? or is there another one?

Ive been to hell and back looking for the fitting that goes in the gas cap. I cant seem to find a fitting that size anywhere. What is that fitting called and what size? Do you have a pic of the fitting by itself before it was installed?

I bought a vent cap with tube from a local motorcycle shop but they only had the ones with black tubing so I wont be able to see if gas is in the tube or not. Where can i get the vent cap fitting by itself to make my own? because i cant get this one off. its like its sealed on there. Im guessing you zip tied the connection.

Thanks
 

sunoco

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#8
there are a thousand ways to do this.-- this works for me.- i do not use a one way valve. i use the filter you see in photos- this will to an extent filter the dust & dirt from getting into gas tank- i back flush the filter often. as for tha gas cap- see the photo of the bulb in gas cap-- remove this- you will see the stock one wayvalve-- looks like a squished mushroom with a stem - remove this.- in photos see the dubro pressure fitting-- ignore the part number-- buy this one-- dubro part # 241 this one comes with nut & gasket 3 dollars. drill a hole in center of gas cap-- then reassemble gas cap.-- agan, i do things diffrently-- the xb-xt gas tank has a dent in bottom of gas tank- i use the o.s brand bubbleless clunk- in gas tank-- remove the red o-ring- its silicone- gas will melt it-- go to hardware store- plumbing area- find a slightly larger black o-ring- put this on bubbleless clunk-- use a 2nd dubro final filter outside the gas tank as seen in photos.-- the bubbleless clunk fits nicely in xb-xt tanks- down in the dent inside gas tank-- this filter will not lean out the engine with air bubbles like all the others do.--- its not cheap.-- hobbytown should have more in stock soon-- oh- use a piece of a foam air filter to loosely stuff inside gas caps rubber bulb opon reassembly-- this will slow down gas spillage somewhat-- clean the gas cap-final filter often.-- these cars are like my dog- low to the ground and love too stir up the dirt & dust-lol.
 

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pfrederi1

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#9
Thx for the detailed info. Ill order online. for some reason i thought i read somewwhere someone said just go to your local hdw store and get the fitting. Looks like this one is only sold at hobbystores. Either way great info.

Thx guys
 

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