Carb Vent Hose Fix by Tim McAdams

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Carb Vent Hose Fix by Tim McAdams

Postby 4Strokes » Fri May 27, 2016 10:59 am

Topic: Carb vent hose fix - by Tim McAdams
Author: ThumperTDC
Posted: 02/04/2004 11:55:35 AM

Team Sobe Suzuki's Tim McAdams has been tuning bikes for well over a decade, and he currently builds and maintains the race bike of French speedster Mathieu Lalloz. We asked "Tool Time" for a quick tech tip, and he said that one of the first things he does to a new bike is get control of the carburetor vent hoses.

"One of the easiest, quickest things you can do for your bike that will spare you future headaches is to get all of your carburetor vent hoses organized and clipped together. From the factory, the hoses are way too long, and you'll notice them hanging down below your bike's frame. If you leave them long and dangling like that, there is a good chance that they will become smashed, mangled and clogged with mud. Keep in mind that if these hoses get smashed shut or clogged with mud or dirt, they will make your carburetor vapor lock and cause your bike to run poorly or even cause your bike to stall out completely."

"If you haven't trimmed your carburetor vent hoses, turn your gas tank's fuel petcock off and lean you bike over. Chances are good that your vent hoses are a mess and that at least one of them is either smashed shut or clogged up."

"You should trim the hoses so that they just barely extend past the bottom of your frame. When doing so, cut them at an angle, not in a straight line. Why? If you trim each hose at an angle, you will effectively give each hose a larger opening that is less likely to become clogged with mud. (Check the photo above for more detail.)"

"After you have trimmed your hoses, tape them together with electrical tape where they are routed alongside one another. There are usually two vent hoses that are routed down the outside of the engine cases, in front of the countershaft sprocket, and two or three that run down the back of the engine cases, next to the rear shock. The wire brackets that are designed to keep the hoses in place are not always fool-proof, and taping them together not only keeps them looking neat and organized, but eliminated the chances of them becoming entangled, as well."

"At Team Sobe Suzuki, I actually replace all of the carburetor vent hoses every couple weeks, because the gas causes them to harden up. This is excessive for the average rider, of course, but we can not afford to take chances. If your hoses are all hard and discolored, consider replacing them. They are not expensive, and doing to is a cheap investment that will help your bike running great."

By Team Sobe Suzuki's Tim McAdams

Reply by doubleodevine on 05/02/2004 7:41:46 PM
good article...i am going to the hobbyshop tomorrow actually to buy some new tubing to replace the stock on my bike and ill use the angle cuts for sure!

Reply by doubleodevine on 05/19/2004 8:29:00 PM
update: i went to the hobby shop...they only carried fuel lines for glo fuel, which is used in model airplanes/cars/boats. these lines will be eaten by gasoline so make sure to read the hoses/packaging. i had better luck going to the hardware and finding 1/4 inch tubing that was orange/red and looks trick. i paid like 1.99 for 3 feet but i should have gotten 4

Reply by Stu on 05/22/2004 12:20:41 PM
I don't know where I read it but it was recommended that the carburator vent hoses be routed up and into the air filter box rather than down. It further stated that the crankcase vent hose should also be routed up and not down, and that if it goes into a "T", half going down and the other half going up, to remove this "T" and just use one piece of hose going up and into the air box with a small crankcase filter attached to the end.

The reasoning was to keep water and dirt out of the crankcase and carburator. Sounds like a good idea. Going through realtively deep water once I remember my engine dying. Once I was out everything was fine. Can't help but think it was because the carburator vent tubes were starving for air while in the water.

I just received some hoses I purchased from my mcmaster carr. I got both Ozone-Resistant Hypalon Rubber Tubing (pn 51195K27) and Acid-Resistant Neoprene Rubber Tubing (pn 5034K23), the only two types that said it was rated for gasoline or fuel.

Reply by doubleodevine on 09/11/2004 6:51:37 PM
i've done that with my crankcase breather. i swear the bike runs better. i just ran the hose under my seat and down into the airbox. the carb vents also go to the airbox

Reply by maximo on 10/22/2004 12:50:16 PM
Are you sure the glow fuel tubing would be eatin by the fuel? I'm an R/C airplane guy and the fuel has a whole bunch of stuff in it like nitromethane, alcohol, castrol and synthetic oils, and a whole bunch more stuff. It doesn't get eatin up by that fuel, and that fuel is pretty harsh when you get it on your skin. The tubing is made out of silicone.....isn't silicone ok around fuel? Also, would it really get hit with fuel that much unless you dumped the bike due to that fact that they are vent lines?

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Re: Carb Vent Hose Fix by Tim McAdams

Postby honda4wheeler222 » Sun Jan 15, 2017 9:05 pm

Hello. I am having a problem with my 2006 honda trx 450er. It absolutely does not want to idle. It won't idle for more than 2 seconds before it dies, however it will run if I give it gas. I have cleaned the carburator, however I did find some dirt up in one of my vent hoses. I mean I would think it would idle longer even with dirt in the vent hose. Do you think that is the problem and do know guys know anyone that has experienced this with the 450r? Thanks!

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Re: Carb Vent Hose Fix by Tim McAdams

Postby JoeRC51 » Mon Jan 16, 2017 8:49 am

Clogged pilot jet.

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