Someone posted some information on tuning modifications on their ATV after installing a snorkel for the airbox and for the exhaust pipe. I don't remember the specifics and wanted any help someone can provide. He had found that after installation, he could not get the motor to run, and had to change the air/fuel mixture, etc. I am curious as to what the snorkel additions are likely to result in and what adjustments I should be prepared to make to have my motor breath and run correctly. Thanks for any advice.

 

TxDoc,

Gordon would probably explain this better, but I will attempt it.

Given the fact that your current air intake, jetting, and exhaust are "matched" - If you change the parameters to allow "more air" to pass through the system, you have to increase the fuel "jetting" to match accordingly. If you do not have enough jetting, your engine will run "lean" - This is a bad thing. The engine will run hotter. If you have too much fuel for the air - the mixture is "rich".

Neither situation is desired.

I would guess the jetting probably had to be increased, due to the Snorkle(s) allowing more air to get to the carb/engine. IMO.

If I'm wrong - ignore me

Happy trails



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Steve "Bog Hog" West

Honda 300 4x4 - Gordonized, Powered and Vamped

 

TexDoc (Fellow Texan),

I have snorkeled the airbox on my 300 4x4. I didn't have to make any changes to my jetting, etc. I don't think I really changed the amount of airflow that was coming into the box, I only changed where the intake was routed. I removed the stock snorkel/hose from the airbox and replaced it with a piece of that blue flexible hose used for pool vaccums. I found this at Loew's or Home Depot. I ran the hose up under the gas tank and brought it up in front of the handle bars and through the space in the plastic dash piece that the throttle, brake lines, and wiring are run through. I then used a 90 degree PVC fitting to top it off. The bike runs fine and is not too lean or rich. If you do this, get a new spark plug and run it for a little while and then remove the plug to make sure that it is grey or black. If it is white, you will want to richen your carb up by going up a jet size or lowering the clip on the needle one notch. I really don't think you'll have any problems though. I have not snorkeled the exhaust.

Since snorkeling the intake I have added the Highlifter power kit. With the Supertrapp having less back pressure I have not had any problems with the machine bogging out with the exhaust under water. Good luck, let me know if you have any questions.

 

TexDoc,
Forgot to mention. I think the previous posts about snorkels you were mentioning were for a Foreman. I think they were using several small hoses routed to the airbox. I think they were experimenting with the number of hoses to use. I don't think you'll have these same problems if you use the flex hose that I mentioned in my post above.

 

Well put YamaHonda.

I remembered about the plug colors, but couldn't remember which way it was.

I also think the additional jetting was required when they "added" air hoses.

I had to modify the jetting on mine when I went to a less restrictive K&N filter and the SuperTrapp exhaust.

Happy Trails

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Steve "Bog Hog" West

Honda 300 4x4 - Gordonized, Powered and Vamped

 

Hey, I appreciate the replies. I have printed them out because you know what happens to valuable info sometimes. I have a friend who can weld anything. I am going to get him to weld the exhaust extension on for me (as Highlifter did to their "500" Foreman) and route the other tubes for the air box. I appreciate all of the help and suggestions. If this goes OK, I plan plan on having the parts ready for a Rubicon and some 28" Vampires (if it can turn them without braking some drivetrain parts?). Thanks again.

 

If anyone could direct me to some snorkeling info on the Foreman i would appreciate it. I tried it on my own but had tio revert back to stock and re-engineer it! Still in the works now! I also hope to have to new Vamps as soon as possible!


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SwampMonster