Water crossings and the essential carb vent snorkel

[RedMesa]

Arizona has been getting heavy rain and snow recently so I have been doing a lot of creek crossings. Water depth is mostly 12 inches with maybe 20 inches in spots: top of cases. Strong current and loose sand in the main channel.

The KTM riders disappear in a wall of spray, of course. Their image requires this. I chug through to minimize splashing but when the sand gets deep it is full blast.

If there is current and enough room I angle slightly upstream into the current. Two reasons. First, the front wheel acts like the bow of a boat, slightly dividing the waters. Second, it reduces the cross-section of the bike that is getting pushed downstream.

Naturally the 230F handles all this like a marine pig storming the beach but there is one critical mod.

Like many bikes, the stock 230F will stall out if the fuel bowl vent tube is blocked even briefly. Airflow and thus gas flow are interrupted. A good splash can do it.

The vent tube descends to a little clip just behind the right footpeg. On my bike this is about 15 inches off the ground. To keep the bike running when the bottom is submerged, I added a snorkel or “T-mod”.

Here is how to do this: http://bit.ly/2Cg8Y6q

If there is any possibility you are going to be doing crossings, or even riding through deep puddles, do this mod before you need it. Stalling in water is not a good thing. If there is current, the bike may go under. That would not be a good day.

Edited March 14, 2019 by RedMesa

[RedMesa]

A few pix. There is one video clip about a cactus.

http://bit.ly/2F07NIR

[Chuck.]

+1

Some carbs like the FCR have many vents, some for overflow and others to vent the float bowl, and sometimes combo overflow/vent. The FCR has a maze of hoses; some go down and some go up, which can be confusing when routing the hoses.

Some carbs; like the PWK and the PDs used on the XR200s have castings for vents that are not drilled for use. The result is the carbs tend to flood if the bike lays with the unvented side down. Not a problem if your bike is well behaved but mine have an attitude and protests my riding by laying down on the job. My fix has been to drill those unused castings and connect vent/overflow hoses, also with a Tee and route the vent end up under the gas tank.

 

[RedMesa]

Just now, Chuck. said:

Some carbs like the FCR have many vents, some for overflow and others to vent the float bowl, and sometimes combo overflow/vent.

Good point. I remember an expensive "manifold" was available for the Xtrainer carb to manage all the hoses and take them up or down as needed.

[Tom Droze]

+1
Some carbs like the FCR have many vents, some for overflow and others to vent the float bowl, and sometimes combo overflow/vent. The FCR has a maze of hoses; some go down and some go up, which can be confusing when routing the hoses.
Some carbs; like the PWK and the PDs used on the XR200s have castings for vents that are not drilled for use. The result is the carbs tend to flood if the bike lays with the unvented side down. Not a problem if your bike is well behaved but mine have an attitude and protests my riding by laying down on the job. My fix has been to drill those unused castings and connect vent/overflow hoses, also with a Tee and route the vent end up under the gas tank.  

Mine will be easy because my XR250R carburetor already has the T fitting, so all I need to do is attach another float bowl drain tube, and connect and route the other tube up high.

[Tom Droze]

All done. . .

[Chuck.]

11 hours ago, Charles13 said:

Hey Chuck,

 

I had no idea what I got until I read the sticky on this forum so; the build will be focused around this forum, I already bought the motor parts from Greenhuman and an 86 cr125 front end. I will be tearing the bike down on Sunday and sending the frame and swingarm out for powder coat (I am still mulling over an aluminum swing-arm and race-tech shock). I have a totally modified Ktm RFS bike for trails but this little bike has me quite excited, I really appreciate all of the input

 

 

5 hours ago, Tom Droze said:

 

Mine will be easy because my XR250R carburetor already has the T fitting, so all I need to do is attach another float bowl drain tube, and connect and route the other tube up high.

 

Not good. The top hose is a float bowl vent, the lower is an overflow vent. I would route the lower overflow vent directly down. The upper vent should go up because it is a float bowl vent, and down to dumpgas on tip overs.  So  you should consider using Ts on upper vent so it can dump fuel when the bike is on its side.    To me it is is more important to have float  bowl vents on both sides of the carb to dump fuel for left and right tip overs.

And keep the vent lines away from the exhaust.

[Tom Droze]

Not good. The top hose is a float bowl vent, the lower is an overflow vent. I would route the lower overflow vent directly down. The upper vent should go up because it is a float bowl vent, and down to dumpgas on tip overs.  So  you should consider using Ts on upper vent so it can dump fuel when the bike is on its side.    To me it is is more important to have float  bowl vents on both sides of the carb to dump fuel for left and right tip overs.

And keep the vent lines away from the exhaust.

 

 

The picture you posted on was how my carburetor came from Honda. The attached picture below is the after, I did exactly as you suggested, the top vent now vents both up and down. . .

[RedMesa]

On 3/14/2019 at 8:01 AM, RedMesa said:

Like many bikes, the stock 230F will stall out if the fuel bowl vent tube is blocked even briefly. Airflow and thus gas flow are interrupted. A good splash can do it.

Update. Well maybe not. GavMac78 and Dustin have been riding through case deep water without mods or problems. 

My KLX250s and AJP were very sensitive and I had some scary experiences with almost stalling out in cold CO creeks. Like going down to 300 rpm for what seemed like minutes.

Anyway glad I have done the mod if it saves one stall-out. But apparently not as essential as I thought.

Edited April 14, 2019 by RedMesa