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YAMAKAZE

Large Tank Fuel Line Routing and Carb Vent Routing

11 posts in this topic

If a A picture is worth a thosand words...... Then....

My 99 WR400F and YZ400F are setup identical.

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nuff said

Bonzai :)

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As usual, and from what I've seen of your past work, the venting and routing looks way trick (reason enough) . At the risk of seeming dim, what else did you gain from this ? I look at the stock venting dangling under my WR450 and wonder about scraping them off on rocks/ledges, choking off the carb mid-stream, or otherwise missing out on some wisdom regarding tank and/or carb venting in general.

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Very nice Yamakaze! The carb vent routing looks great. Looks like WR450 owners will be hard pressed to mount the vent box in the airbox though.

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Sweet Kaze :)

FYI on the PC Carb Vent-

The velcro comes off from inside your airbox pretty easily. Mine just dangles in the airbox now. If you haven't already, some good glue on clean surface may be the ticket to getting it to stay put.

Ya know, that clear tank looks sweet on the blue beast.

Take care Kaze,

Fryboy

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The reason for the vent change was actually two fold. The first was because my Foster Kid was racing the WR and everytime that the lines got caked with mud (Every race this year has been a mud fest) the carb would vapor lock and shut down. The only way to get it rinning again was to clean the vent lines and get the air flowing again. I think that most of this was caused from fuel flowing out of the tubes for a long time and the constant heating and cooling caused the tubes to react like shrink tubing and constrict the flow of both fuel and air. Initially I just replaced and routed the top vent lines to the air box and the bottom lines downward. However the first time out it vapor locked again. It had something to do with Bryan's crashing and the top lines had gas in them and lock up the entire vent system. I decided to go with the PC Racing vent system after talking with a couple of the GNCC pro's mechanics and getting the low down on proper vent/drain dynamics.

Since the installation I have literally burried both bikes in the mud and have not had anymore problems.

We additionally had problems with routing the right side fuel line across the front of the carb as the heat from the head coupled with the movement of the hose while riding was causing some serious chafing and was only a matter of time before it would have been cut and sprayed fuel all over a hot header.....Roasted gonads are not a favorite of mine. So, we routed the hoses on both bikes across the intake side of the carb and it works great without the danger.

Bonzai :)

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Cool picks....great idea.

I rode my WR450 for the first time today.....problem with tank breather hose spit'n fuel out. Thouht the valve was to stop this. Turned assembly end for end and fixed problem. Valve arrow points away from tank. Any suggestions?

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Initially I just replaced and routed the top vent lines to the air box and the bottom lines downward. However the first time out it vapor locked again. It had something to do with Bryan's crashing and the top lines had gas in them and lock up the entire vent system

Wow out of a lot of bikes that route the line up this is the first time I have heard of this problem, (I personally have done 4 bikes this way). Quite the combination to get it to lock up, mud clogging both down tubes, and gas in both up tubes. Must have been a good crash and low points in the up tubes. It could happen even if you have 6 vent tubes, when they are T'd too, if the low points are not eliminated. Lots of tubing and connection too and to complicated for a simpliton like me. Clean job and nice pics though, good job!!!

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Just one more question, if you care to answer. While I agree on this and have ordered the PC racing kit for the vent tubes, where did you route the "down" tubes if not through the stock routing ? Overflow gas must go down, but to where ?

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Notice Pic #3...The line on the bottom T that looks slightly different in color is the down tube. Both sides are the same. You will go from 4 tubes downward to just 2. Route them through the stock locations.

Also...Where the directions say to cut off 3 inch sections (DON'T)...Just cut them to fit over the airbox outlet....Three inches is nott enough...You will still have plenty of hose left over to complete the job.

Good Luck....

Bonzai :)

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Thank you, good advice. Looking forward to your next mod. Always thought out, and well executed.

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