No overflow tube? - Kawasaki KLR 650 Forum
1987 to 2007 Wrenching & Mods For maintaining, repair or modifications of Generation 1 KLR's. 2007 and earlier.

 
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post #1 of 9 Old 07-04-2016, 09:58 AM Thread Starter
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No overflow tube?

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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post #2 of 9 Old 07-04-2016, 11:21 AM
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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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post #3 of 9 Old 07-04-2016, 11:34 AM Thread Starter
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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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post #4 of 9 Old 07-04-2016, 01:05 PM
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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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post #5 of 9 Old 07-04-2016, 01:46 PM Thread Starter
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Come to think of it, the KACR system would probably prevent any serious hydrolock condition.
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post #6 of 9 Old 07-04-2016, 04:35 PM
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Quote:
Originally Posted by drumstyx View Post
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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post #7 of 9 Old 07-04-2016, 06:47 PM
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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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post #8 of 9 Old 07-04-2016, 07:43 PM
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Quote:
Originally Posted by Damocles View Post
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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Still riding my 1987 KL650-A1. 84,000+ miles & counting
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post #9 of 9 Old 07-04-2016, 09:09 PM Thread Starter
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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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