03 WR450 carb vent question????????

5 replies to this topic
  • foursmoke

Posted February 19, 2004 - 02:18 AM


Does anyone know if it is ok to run 2 of my carb vent lines up & under the tank, under the seat and just let them hang in the top opening of the air box? They are secure w/cable ties at the sub-frame just b-4 entering the top of the air box so they won't bang around. I was just going to run them under the tank but feared water geting into them during high speed puddle or deep water crossings. I would also like to put a (T) on the engine head vent and would rather not drill a hole in the bottom of my air box like suggested on the Motomans site. My plan was to cut & (T) 2-3" from the head,run a short(5-6") piece with a 90 degree elbow and then another short piece of hose(4-6") pointing downward(possibly with a vent like cap) to prevent water from getting in it and running down & into the top of the head. Any other suggestions would be greatly appriciated.

Thanks,foursmoke :)

  • endurodog

Posted February 19, 2004 - 02:48 AM


That is how I have my vents tubes on both of my bikes, also on my last 4 others too. I have no problem in water crossings with the bike dying either. Was on a week long ride with a guy a couple years ago on a DRZ and his bike died in almost every water crossing. On that bike it was hard to get to the vent tubes but we were able to get 1 and route it into the airbox, he had no further problems with water crossings on the trip.

  • Indy_WR450

Posted February 19, 2004 - 04:47 AM


Ditto, I have been running 2 hoses up the left side of the bike along the airbox and down inside for almost a year. No need to cable tie or do anything if you route them along the frame rails. Deep crossings do not screw up your venting this way. I run mine right to the bottom of the box and if you get water filling up your air box you will choke off the carb and stall the bike before getting water in your engine! What are Yamaha engineers thinking! That should be the standard! Set a hose from each side up over and into the bottom of the airbox! Stock length works perfect if you route them up over the carb and along the left side sub frame and then straight down the stock air box snorkel. :)

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  • ETP

Posted February 19, 2004 - 05:06 AM


I put tee's on mine, and the crankcase vent tube, routed the new lines up by the back of the tank, then tied them together with a foam cap wrapped around the ends. The tee's are for any blowby to drop thru the down tubes. Didn't think I could route into the top of the air box as Indy has. Space is kinda tight up there. Maybe I will extend mine over to the sorkel.

  • foursmoke

Posted February 19, 2004 - 04:45 PM


I have the carb vent hoses already in place and secured, the other 3 hoses are out of a "extreme weather" carb vent kit and have one way check valves on them. All 5 hoses have filter caps on them and are a very nice color blue to boot :). I also have decieded to " T " off the crankcase vent about 3"- 4" and run a hose over to the air box, drill a hole in the bottom left side of the air box, thread a barbed connector thru the wall and seal it. It's alittle bit more work than I wanted to do but the bike is cleaned and greased from top to bottom so this will be the last thing I have to do b-4 riding starts up again. BRING ON SPRING :D

Smoke :D

  • endurodog

Posted February 19, 2004 - 05:03 PM


I see where someone runs a T vent for proper draining of fluids from the tubes. This made me remember to clarify this point. The carb has tubes coming off of either side. 1 goes up, 1 goes out, off of each side of the carb for a total of 4 vent tubes. Route the ones going up to the airbox, this will drain any fuel that gets in to the lower tubes and out.

Years ago carbs only had 2 vent tubes, 1 from each side. That made it so you had to add the T's. A few years ago the manufactures T'd the tubes for us at the carb thats why we can get away with out adding the extra hardware now.


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