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Last weekend I was off road with my son. We when through a big puddle that got deeper than expected (14"). My son was ahead so I knew it was coming, I was going relatively slow in first, as it got deeper I just kept a steady throttle but my TW just quit, right in the deep spot. I know the depth, because I had to get off and push and the water came in at the leak point of my mx boots. I'm pretty sure I have crossed deeper creeks and gone faster before, thus splashing water higher. I can't figure out why my bike died. There was no water to the air box, the carb was not even close to being in the water. I took the spark plug out and it looked fine. Smelled gas so I'm pretty sure it flooded. Waiting about 15 minutes and it started up. Anyone know what might be going on?
 

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It could be the result of your carb vent line being submerged. This is fairly common problem on KTMs and some folks go as far as to modify their lines to vent up near the headstock.



It sounds like you didn't suck any water through the intake, so that could be the culprit.



Regards,



Mr. BigWheel
 

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This has happened on multiple occasions while my daughter rode through very similar conditions and for the life of me I could never figure out why it happened. As you described, it smelled flooded and took about 15 minutes of waiting before it fired up. sounded kinda rough but smoothed out in 5 minutes of riding. I always figured it must have been electrical because there was never any warning signs and it always just died. Didn't happen at every water crossing but occurred enough to make ya weary as to whether to cross through the water at all.
 

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Sounds like a good winter project would be to use a can of liquid tape on the wiring harness. Waterproofing all the connectors.



If the CDI or other ignition leads are shorted out by water, the bike would not get spark. Flooding would result from the engine turning over a few times while the spark plug was not firing.
 

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It could be the result of your carb vent line being submerged. This is fairly common problem on KTMs Mr. BigWheel
I like Mr. Bigwheel's suggestion. A clogged, submerged vent line has been the cause of stalling on some BMW's also.



That vent line hose hangs down below the frame. How about putting your finger over the open end of the carb vent line while the engine is running and see what happens. I would try it myself but won't have access to my TW until this weekend.





jb
 

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I'm going with Mr. Bigwheel's & lizrdbrth's explanation of this problem. Just makes more sense to me being a vacuum line thing vs electrical.



This was discussed in the older forum format and aside from the debate about what constitutes a short circuit it sounded conclusively like an electrical problem. I followed that thread pretty closely and never gave it much merit because my Dub had stalled in deep water crossings only going about 5 mph or less. No way the water was getting into the air box , spark plug dry etc...



here's the old thread:

http://tw200forum.com/forums/14402/ShowPost.aspx
 

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Discussion Starter #7
Thanks for the replies. Bigwheel/Lizrdbrth - carb vent wasn't anywhere close to sucking water though. I re-read that original post in the old forum and two things made me wonder - sparkplug wire (at the plug) and kick stand shutoff. The only big clue I have is the bike flooded - after I pushed it out the puddle (without having tried to start it yet - I could smell gas - and I hadn't dropped the bike) - so that points more towards the carb vent though. However, after I had the bike ashore, it would not start and I do believe I was not getting the plug to fire - which points to electrical.
 
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check the wires coming out of the side cove from excitercoil assembly possible they have the insulation worn off allowing the water to short them. just a thought.
 

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As shallow as the water was, it was most likely the carb vents that caused the bike to flood/die. This is more common than many folks seem to realize; they are more likely to blame electricals. I'm not saying electricals can't get wet and kill the bike, just that most folks immediately blame electricals when they have a water issue, and don't consider the carb vents. Shallow water kills are usually a carb vent issue.



The fix described previously is a good one. Tee in each line; one line routed to the airbox or high on the chassis, the other routed to the stock location. The bike will breathe out of the high line when the lower is submerged, and drain through the lower line when needed.
 

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EDIT: Vuldub recently pointed out that I never finished posting the carb vent mod. I've redone the entire post and 86'd the old ones as I've revised the mod a couple of times since. I mocked it up on a spare carb for illustration purposes, but you don't need to remove your carb to do the mod. Takes about 10 minutes once you gather all the parts. The same method serves both the old and new style carbs.



The stock setup. In water crossings the end of the vent tube gets submerged and becomes blocked:















Here's what you'll need to fix it:









I used cheap vinyl tubing for the pics. The white "tees" are 3-way 3/16" vacuum fittings, available at any auto parts store. Two weedwacker fuel filters (don't fuss over these, they're pretty generic. They're only there to keep the crud out) and an optional lower vent shutoff made from a drip irrigation valve from the local hardware store.



Cut 2 short pieces of tubing and attach them to the carb. Insert the tees, then either re-attach your existing setup or make up a new one from fresh tubing. Attach your new upper hoses to the tees, making one slightly shorter than the other so they'll line up one behind the other. Insert these into the end of your frame's backbone, just above the carb. Make them long enough to get as high up in the tube as possible. Adjust all your tubing lengths as neccessary to make sure it clears the shock spring on the right side and that the lower vent exits the bottom of the bike as before, but don't re-attach it to the J-tube. The J-tube is just a big crap collector/fire hazard and limits your fording depth even further due to its location.



When you're done it should look something like this:











Without the shutoff valve your fording depth is now the depth of your carb, rather than your swingarm. For really deep water you can close the valve and your fording depth becomes the backbone tube.



Don't ever use the valve without re-opening it after a water crossing. If you dump the bike your lower vent could fill with fuel and cause a bike fire. For the same reason, don't even think of doing away with the lower vents and only running the upper.



Note: If you're not into doing the full vent mod and just want to decrease your risk of stalling on flooded city streets, remove your lower vent hose from the "J" tube. You'll find the J-tube attached to the frame behind the motor. Cut about 2 inches off the tube and let it just dangle behind the motor. That way the end of it will stay out of harm's way and sheltered by the wake of your motor in shallow crossings. I'd highly recomend doing this even on a stock bike.




 

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One simple explanation it the sudden cooling by immersion. One of the things I do before entering deep water like that is slip the clutch so that I can keep the engine revved up more as I cross. This helps keep the engine from suddenly cooling enough to stall. You could also go to partial choke, a trick I use on bikes that have a handlebar mounted choke.



Phelonius
 

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Some great ideas here. I had my bike stall during a stream crossing, that was more like 8". After some thought, I suspected/guessed that the water may have shorted my kickstand switch which cuts the engine if you put the bike in gear with the kickstand down. I removed the switch from the kick stand 'set it to the kstand up position' wrapped it in a sandwich bag and zip tied it to the frame under the front part of the seat. The few shallow stream crossing I have done since were without incident. Gerry
 

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Note: If you're not into doing the full vent mod and just want to decrease your risk of stalling on flooded city streets, remove your lower vent hose from the "J" tube. You'll find the J-tube attached to the frame behind the motor. Cut about 2 inches off the tube and let it just dangle behind the motor. That way the end of it will stay out of harm's way and sheltered by the wake of your motor in shallow crossings. I'd highly recomend doing this even on a stock bike.


Done! Great tip.
 

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Discussion Starter #14
Lizrdbrth:

Thanks for taking the time to post the photos, it really helps.



Gerry, where's your innovative missing link award, I think this one deserves it!

...Wes
 

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Another suggestion was to check the seal on the airbox under the seat. With repeatedly taking the seat off/on, the seal on the airbox might be slightlly ajar or the seal itself may be rotten, so when the rear tire kicks up some water, it gets into the airbox due to a poor seal. In my case, my big atv tire kicks up alot of water even in a wee puddle.
 
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Another suggestion was to check the seal on the airbox under the seat. With repeatedly taking the seat off/on, the seal on the airbox might be slightlly ajar or the seal itself may be rotten, so when the rear tire kicks up some water, it gets into the airbox due to a poor seal. In my case, my big atv tire kicks up alot of water even in a wee puddle.


Fine use of double entendre. *insert thumbs-up emoticon here*




 

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Lizrdbrth:

Thanks for taking the time to post the photos, it really helps.



Gerry, where's your innovative missing link award, I think this one deserves it!

...Wes


Nothing all that innovative, just something that a lot of folks don't seem to know a lot about. The basic principle works for almost any carbed bike. Typically the vents get terminated under the tank or the seat, where they still flood if the water is deep enough or if you drop the bike, and they're constantly exposed to mud and dust. We get a break from that on our Tw's in that we have that open top tube as a sheltered airspace. I'll take credit for exploiting the airspace if it makes me look smarter





 

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Nothing all that innovative, just something that a lot of folks don't seem to know a lot about. The basic principle works for almost any carbed bike. Typically the vents get terminated under the tank or the seat, where they still flood if the water is deep enough or if you drop the bike, and they're constantly exposed to mud and dust. We get a break from that on our Tw's in that we have that open top tube as a sheltered airspace. I'll take credit for exploiting the airspace if it makes me look smarter
Well its something that worth it to fix, easy to do and most of use wouldn't know to do it unless someone like you told us. Sort of like the clutch spring, easy, but overlooked. So, thanks!
 

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I held off on the Lizard Guys 'award' because I needed to figure out where the hell all those tubes went and why he did not buy a new TW so he would have a picture of my carb. I then realized that it all looked my heart valve bypass and since I was still alive, it certainly should work on the TW
(just kidding).



Good job lizrdbrth, isn't this your 2ed (3ed?) Missing Link?.... Here is a man that really helps make this a GREAT FORUM.......... I applaud you Sir.. Gerry



to all, feel free to cut and paste the 'Missing Link' anytime you are so inclined.



Lizrdbrth:





Thank You !
 

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Gerry, I think "The Link" oughta remain a "Gizmow" thang.



There's something inherently cooler about it when it comes from you.



Thanks.




 
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