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Discussion Starter #1
First post, first KLR, I'm going to love this bike!

One thing that was curious to me though: As I was cleaning the carb (runs fine now) I noticed there's no overflow tube in the float bowl. Owning a Concours, I'm very familiar with carbs that don't have these, and their propensity for producing lovely bent rods via hydrolock while starting. This is a Canadian bike, which I suspect had more BS EPA stuff applied, and that's why it's missing.

So being that I'd rather not have this sort of failure, has anyone installed their own overflow tube? There's a guy in the Concours world that performs this service, and it's known to save engines all the time. But of course, sending things away doesn't seem to be in the KLR spirit, so I'd like to either try it on my own, or pick up a bowl that has the overflow tube already.

Thoughts? Is the KLR maybe not susceptible to hydrolock due to something I'm overlooking?
 

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Maybe the carb vent tube serves the function of an overflow tube on a CVK40 carburetor; maybe not; just speculating . . .

What path does fuel flow, from the float bowl to the cylinder in cases of hydrostatic lock? Up through the idle jet, through the venturi, into the intake manifold and past the intake valves into the cylinder? Just asking; the carb vent tube may be at a lower height than this pathway and take away the overflow fuel . . .

Regardless, from Internet postings, hydrostatic lock incidents with KLR650s appear few and far between . . .
 

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Discussion Starter #3
I'm quite sure they are, especially given that the KLR's petcock is rather unique in that it's a vacuum petcock with an off position, something I surely plan to use. I could buy a bowl with an overflow tube on ebay for about $70CAD shipped, but again, in the KLR spirit, I want to be as cheap as possible on this thing -- I've got an immaculate bike, this one just needs to work and be badass.
 

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Good point about the vacuum-actuated petcock; my KLR250 and my KLF300 (ATV) have manually-activated petcocks and . . . overflow tubes in their CVK34 and CVK32, respectively, carburetors. My KLR650 has a vacuum-activated petcock, and . . . no overflow tube in its CVK40 carburetor.

An overflow tube in the float bowl of a KLR650, if not an elegant solution to a non-existent problem, would not be high on my priority list. Yet, it's YOUR bike, drumstyx! YOUR preferences are the only relevant ones. If an overflow tube is worth $ 70 CAD to you, install it in good health! :)
 

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Come to think of it, the KACR system would probably prevent any serious hydrolock condition.
That's what I think also. I read of a rider starting his KLR and finding lots of white smoke from the exhaust. It turns out there was half a liter of gas in the crank case from carburetor overflow, but no damage to the engine from hydrolock.

I assume he had a nonstandard petcock.
 

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Regarding hydrostatic lock problems; I think catastrophic damage occurs ONLY if a cylinder (other than the flooded one) fires; the force of the starter motor alone insufficient for serious damage. This circumstance (subsequent cylinder firing) doesn't occur on a single-cylinder engine, like the KLR's.
 

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Regarding hydrostatic lock problems; I think catastrophic damage occurs ONLY if a cylinder (other than the flooded one) fires; the force of the starter motor alone insufficient for serious damage. This circumstance (subsequent cylinder firing) doesn't occur on a single-cylinder engine, like the KLR's.
I will concur with this statement.
 

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Discussion Starter #9
Hmm, interesting point. I don't think research has been done on the Concours to the point that we can pinpoint why or why not damage occurs during a hydrolock. I guess that does make some sense, since there's a 75% chance the hydrolocked cylinder is not the next in the firing order in a 4 cylinder, which would make for a ~75% chance of damage during hydrolock, and thus a reasonable cause for concern in the 4 cyl world, and specifically the Concours'.

This is actually a point I'm confident in banking on, I never did think starter motors had enough torque to bend a rod, but a cylinder or two firing definitely could. I consider myself a fairly experienced motorcycle mechanic, but this is kind of a revelation, as I've never owned a single cylinder bike before.

Thanks all!!!
 

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As a guy who
- changed out his broken petcock (the fuel nipple came right out of the factory petcock)
- with a manual petcock (faster and cheaper than an OEM)
- then PUT THE VACUUM TUBE on the fuel supply
- then started my KLR only to hear a split second regular start followed by the dreaded hard stop and sound of a hammer smashing an anvil......

A definite self induced hydro lock.

After removing the spark plug, turning the back tire to confirm things would move, and then great relief when the starter cycled things very normally. Tank on, right fuel line connected and bingo! Started and was running per normal. I also changed the oil which had a smell of gas, although not visibly full of gas. It also was draining excess fuel like crazy from the carb as soon as it happend.

I have NO idea what that sound is. But I can confirm after fixing it an hour ago, no noted damage so far. There is some kind of drain on the carb, because it's tested that. Of the fuel that did overflow in, TO THE MANIFOLD end, it somehow drained most of it away.

Respect for the might KLR and a noobie making very serious mistakes!
 

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As a guy who
- changed out his broken petcock (the fuel nipple came right out of the factory petcock)
- with a manual petcock (faster and cheaper than an OEM)
- then PUT THE VACUUM TUBE on the fuel supply
- then started my KLR only to hear a split second regular start followed by the dreaded hard stop and sound of a hammer smashing an anvil......

A definite self induced hydro lock.

After removing the spark plug, turning the back tire to confirm things would move, and then great relief when the starter cycled things very normally. Tank on, right fuel line connected and bingo! Started and was running per normal. I also changed the oil which had a smell of gas, although not visibly full of gas. It also was draining excess fuel like crazy from the carb as soon as it happend.

I have NO idea what that sound is. But I can confirm after fixing it an hour ago, no noted damage so far. There is some kind of drain on the carb, because it's tested that. Of the fuel that did overflow in, TO THE MANIFOLD end, it somehow drained most of it away.

Respect for the might KLR and a noobie making very serious mistakes!
Where do you live & where is your KLR from?

The UK and other European KLR CVK carburetors DID have a float bowl OVER-FLOW stand pipe.

The USA & Canadian KLR CVK carburetors apparently NEVER have had a float bowl over-flow stand pipe! But one can be added. :)
Tom Schmitz did, https://www.souperdoo.com/stuff that i think about/installing-a-carburetor-bowl-overflow-pipe-no-fear-of-fuel-hydrolock
 

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I have been reading (new to the site) about petcocks and related problems. I just purchased a 2006 KLR with a seized engine, but only 579 miles! It ran when the previous owner parked it, but not in a few years due to surgeries caused by a 4 wheeler wreck. When his friend poured some fuel into the tank to try and get it started, all of the 3+ gallons of fuel went directly to the crankcase (luckily it didn't turn over or serious damage could have occurred. My question is - could the stock petcock been faulty and let the fuel bypass the diaphragm through the carb into the cases? Also, why didn't the carb floats stop the fuel in the carb?

I have also read about blocks are sometimes used to eliminate the vacuum diaphragm and it appears to work, albeit now a manual petcock (no big deal to me).

Would it be easier/better to install a block or rebuild the stock vacuum petcock? I plan on rebuilding the carb as well.
Thanks for any advice, as I usually work on Kawasaki 900 Z1's and KZ1000;s.
 

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Easy stuff first. I would suspect a stuck float. Allowed gas to go straight down the throat. So, pull the carb, rebuild it. Check the fuel petcock. I'd guess you'll find the problem without playing "what if". Good luck.
 

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The rubber, 4 holed selector disc can become adhered to the fuel valve handle due to in-activity. This can also happen to the manual fuel valve that (too many) owners choose to install. With or without fuel in the tank.
When the handle is turned, it can tear the ribs off of the surface of the rubber selector disc.

These crumbs can be caught in the o-ring seal of the diaphragm operated oem valve, keeping it from closing. But even if this happens on the manual valve, there is NO Way to turn it completely off with torn ribs.

These crumbs can also flow down the fuel line and jam into the float needle & seat, holding it open.

In 2010, Kawasaki put a tiny in-line fuel filter right in the very tip of the Now Non-Removable (but carb gunk safe) fuel inlet nipple. Other models have screens on the brass float valve seat. The KLR has a NON-Removable float valve seat.

The proper part # for the 4 holed "Packing" disc is 43049-1017 & the handle o-ring is 92055-1111. They have screwed-up the KLR parts screens for ALL year models of KLR650's. Gotta' go to KLF300 ATV's to find these proper 2 little items on most parts screens.
 

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PDWESTMAN - Thanks for your reply / advice. I plan on rebuilding the carb and adding a overflow tube. I would like to keep the vacuum petcock, and I'll order the parts you mentioned. Thanks again and I will post in the future on my progress. Still cold in Michigan (40's today and some snow), so it will be a while, but planning my next steps :)
 

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I pulled the tank and took a look at the petcock to see where to start, and I discovered someone had already changed the petcock to a manual one. I also saw a hose and clamp on the carb blocking the vacuum outlet (why won't people leave well enough alone). I have not pulled the petcock off yet (snowing outside) but will probably have no idea who made it to seek repair parts.

I am ordering a rebuild kit for the barb, but I have a suspicion that either the floats stuck or the manual petcock failed which allowed 2 gallons plus fuel go to the lower end. I may be buying another petcock if all else fails. Any suggestions on who sells a good manual petcock, as I see the originals are pricey.

Another thing I noticed (the last guy couldn't leave it alone, and disconnected the kick stand safety switch. GRRR, hope that is all I find.
 

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Eaglemike carries the manual (Yamaha raptor petcock). BTW, manual petcocks and safety switch bypasses, etc. etc. certainly aren't for everyone but since they are all fairly common failure points, I don't run the clutch safety, sidestand safety or vacuum petcocks on my KLR's......K.I.S.S. works for me most of the time

https://www.eaglemike.com/Manual-Petcock-for-KLR650-mpcy.htm

Cheers,
Dave
 

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but I have a suspicion that either the floats stuck or the manual petcock failed which allowed 2 gallons plus fuel go to the lower end.
both things have to happen for your problem to occur (the failure of the petcock can just be failure to turn it off when the bike isn't running). If you want to retain/re-install the vacuum unit, you should be able to find one fairly easily. If you were local, I'd give you one.

Dave
 

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I pulled the tank and took a look at the petcock to see where to start, and I discovered someone had already changed the petcock to a manual one. I also saw a hose and clamp on the carb blocking the vacuum outlet (why won't people leave well enough alone). I have not pulled the petcock off yet (snowing outside) but will probably have no idea who made it to seek repair parts.

I am ordering a rebuild kit for the barb, but I have a suspicion that either the floats stuck or the manual petcock failed which allowed 2 gallons plus fuel go to the lower end. I may be buying another petcock if all else fails. Any suggestions on who sells a good manual petcock, as I see the originals are pricey.

Another thing I noticed (the last guy couldn't leave it alone, and disconnected the kick stand safety switch. GRRR, hope that is all I find.
This should be the proper model for the most common manual fuel valve sold for the KLR650. Repair parts are available.
https://www.yamahapartshouse.com/oemparts/a/yam/50038f48f870021f60a0c790/fuel-tank

I personally would Really Hate having only about 10-20 miles of Reserve fuel supply. Thats 10 miles on bouncey dirt roads, because it splashes a lot of the RH side fuel over the center hump. Leaving very little to 'tip-over' for secret reserve.
I like the oem 20-40 miles of reserve.
And I have yet to see a pic of a successfully lengthened manual valve ON straw. Maybe Dave Pelletier has a pic?
 
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