Kawasaki KLR Forum banner

1 - 20 of 50 Posts

·
Administrator
Joined
·
8,601 Posts
Discussion Starter #1 (Edited)
I don't like the KLR vacuum-operated petcock. I think it's a problem waiting to happen, and I got in the habit of reaching down and shutting motorcycle petcocks off thirty years ago.

One of the first things I did to mine was remove the vacuum operated stuff and install a blanking plate and gasket. The first time I did it, I have to admit, I did a shoddy, quick job of it and it leaked. The second go-round was better executed, but I still wasn't really happy with it.

vatrader happened to mention (http://www.klrforum.com/showthread.php?t=6341&highlight=vatrader&page=2) that there is a petcock available that is stock on a Yamaha 660 Raptor that is a drop-in replacement.

I couldn't resist and, since I had an order brewing with Ayers anyway, I added one to the cart.

I wasn't sure what to call this, as it isn't a farkle, nor is it a mod. Given my distaste for the vacuum-operated petcock, I decided it was an upgrade. I owe vatrader for the 411 on this, hence the name.

Here's a comparison of the two units:



Obviously, the reserve tube is much shorter. Looking at it, it would be easy to extend to the stock KLR length, but I've never relied on reserve to tell me when I need gas, so I left it alone. If you don't modify it, and you go on reserve, GO GET GAS!!

Installing it is as simple as removing the tank, pulling the two bolts out, and installing the Raptor petcock. Torque gently on re-installation. The stock fuel hose works with no modification, but the position is different, which calls for some trimming on the solenoid cover.





The finished view:



Tom
 

·
Threadjacker
Joined
·
6,768 Posts
I don't know what's manlier...those sheets (couch cover?) or your vintage sewing machine. ;)

Have you sewn a flowered cover for your bike yet?

I have the opposite problem. KLR has me spoiled. Now when I ride my Honda I have to check like 8 times if I turned off the gas. Used to be automatic.
 
  • Like
Reactions: Uncle Dick

·
Administrator
Joined
·
8,601 Posts
Discussion Starter #3 (Edited)
Hey, mum's the word on the sheets.

I almost got busted last weekend when I was using her iron to glue some oak shelf edging onto some new shelves. The iron got put away about 10 minutes before she got home.

If she finds out about those sheets... I really did get most of the gas out of the petcock and I wiped it off before I set it down.

See, if we're laying in bed and she says "How come the sheets smell like gas?" I have some plausible deniablilty. I can say "I don't smell nothin'" or "Sorry, honey, too many pickled eggs and beer over here". But if she actually finds out I used the sheets for a photo backdrop, well, that would really harsh her mellow. That would be bad for me.

Tom
 

·
Threadjacker
Joined
·
6,768 Posts
Allright, then my lips are sealed. But if called to testify, I cannot lie.
 

·
Premium Member
Joined
·
1,263 Posts
Glad to have helped! Like you, I don't rely on the reserve feature to remind me to fuel up. There are bad things that live in the last dregs of a fuel tank, kinda like the bottom of the cup of coffee, brewed in a percolator. Eliminating the vacuum actuated fuel delivery was my goal. Where do you start to diagnose an intermittent fuel problem when you are using vacuum powered fuel delivery? This new set up has served me well, and I am sure you will have no regrets.:60:
 

·
Premium Member
Joined
·
1,263 Posts
I'm not Tom, so take this advice with a grain of salt. Stuff a bolt, screw, something in the tube end that WAS attached to the tank. Gotta be plugged.
 

·
Administrator
Joined
·
8,601 Posts
Discussion Starter #8
Yup, you can just plug it off with whatever works that you have handy.

If you go to the auto store you'll find a carded package of general purpose vacuum caps in various sizes; you can use one of those, too. There's a seperate vacuum line that goes to the carb. Just pull it off and put a cap on. They tend to rot and crack a bit, but they don't seem to leak. I find that the rotten rubber look complements the other rubber on my '08.

At a good hardware store you'll find screw protectors. These are small, flexible plastic caps that come in bright colors. They seem to seal pretty well and don't rot like the rubber vacuum caps do.

Tom
 

·
Registered
Joined
·
576 Posts
Bump....

I got two questions:

1) Does this work (the Yamaha 660 Raptor model) for the older models of KLRs?
2) What exactly is the problem with vacuum based petcocks? Personally I've noticed that my engine runs smoother when my tank is full (less stumbling). Would there be an advantage for me to do this upgrade?

I'm about to take the tank off in about a week anyways, so I figured I'd just ask away.
 

·
Registered
Joined
·
5,738 Posts
Bump....

I got two questions:

1) Does this work (the Yamaha 660 Raptor model) for the older models of KLRs?
2) What exactly is the problem with vacuum based petcocks? Personally I've noticed that my engine runs smoother when my tank is full (less stumbling). Would there be an advantage for me to do this upgrade?

I'm about to take the tank off in about a week anyways, so I figured I'd just ask away.
I THINK the Raptor petcock is universal to KLR's of all generations.

Ain't nothin' wrong with an OPERATIONAL vacuum-actuated petcock; folks disable the vacuum apparatus to avoid an area of possible malfunction.

IMHO, there is NO OPERATIONAL PERFORMANCE IMPROVEMENT POSSIBLE from switching to a manually-actuated petcock.

Nor, at least measurably, from a full vs. near-empty fuel tank.

Why not? The carburetor ingests its fuel from the Bernouli Effect, unaffected by the hydrostatic fuel pressure.

Further, a mythological tale exists, claiming hydrostatic fuel pressure can be increased by cutting the height of the "straw" on the petcock, when in fact the fuel pressure at the carburetor is determined solely by the height of the "head," the vertical distance from the carb inlet to the fuel level; straw height is of no consequence.

Cutting straw height WILL decrease reserve fuel supply volume, according to Mr. Archimedes.

So, you don't want no stinkin' vacuum-actuated petcock? Convert to manually-actuated only (remembering it's up to YOU to shut 'er down when you stop). Want to prevent, automatically, fuel spills into the engine/out the dump tube from malfunctioning float valve when engine is OFF? Live with the stock petcock, tolerating its risk of malfunction.
 

·
Registered
Joined
·
35 Posts
Guess I need a little help with his. Perhaps I got the wrong petcock but it only has one nipple. What do I do with the other (vacuum) hose? This is on an 04.
 

·
Administrator
Joined
·
8,601 Posts
Discussion Starter #12
If you bought the Raptor petcock, you got the right one. It is a normal, non-vacuum-operated petcock.

Simply remove the vacuum hose from the fitting on the carburetor and block it off with a vacuum cap.

T
 

·
Registered
Joined
·
783 Posts
Just finished putting in the vacuum-less Raptor petcock, even installed it without pulling the tank. (I love 1/4" drive swivels)

Now the question is, has anyone really found out how many miles you can get between switching to reserve and EMPTY?

I've always been really consistent with running out of fuel at 212-220 miles, then switching to reserve.

Let me back up a little. 2008 Gen II with a 688 kit on it, and I average 45 MPG around town and short trips.
 

·
Premium Member
Joined
·
3,304 Posts
Congrats; Like Tom, I consider the Raptor petcock a useful upgrade that increases reliability. Yes, I've had the reserve discussion before (cough, elsewhere, cough) and can't check currently but if memory is correct I believe it was around 15 miles.....

Of course you can always swap reserve straws and maintain the stock reserve capacity. Me? I know how far my bike will go on a tank (plus I can see my fuel level from 10' away with my translucent IMS tank) so I don't rely on reserve anyway.

cheers,
Dave
 

·
Registered
Joined
·
3 Posts
At 70 mph I went 7 miles before having to pull over to lay it on it side for the secret stash on the right side. Luckily I was on my off ramp when I had to lay it over.
 

·
Premium Member
Joined
·
7,318 Posts
Of course you can always swap reserve straws and maintain the stock reserve capacity.

cheers,
Dave
Actually Dave, one would have to "swap the ON straw". You know, the Tall one. vbg
But I don't think that could be very easily done, I never seen a loose one. Might wind up with 2 un-useable petcocks.
 

·
Registered
Joined
·
783 Posts
Actually Dave, one would have to "swap the ON straw". You know, the Tall one. vbg
But I don't think that could be very easily done, I never seen a loose one. Might wind up with 2 un-useable petcocks.
I've already chucked up the old petcock in the vise and tried to move that tube. It's not an option at this point, started to crush the tube. I might try a hot wrench later if I really want to re-use that long tube.
I just like knowing how far I've got. I did a little research a while back and found;

220 miles to reserve
36 miles to empty, then rocked it over on its side for secret reserve
17 more miles until it was "empty"
1/2 gallon fuel bottle got me three miles to the station.

Thanks guys, I'll start running this tank down and see what I get.
 

·
Premium Member
Joined
·
3,304 Posts
Actually Dave, one would have to "swap the ON straw". You know, the Tall one. vbg
But I don't think that could be very easily done, I never seen a loose one. Might wind up with 2 un-useable petcocks.
Doh! yep, true enough; the tall straw.

On the straw swapping; I haven't tried it, but at least a couple people had said they'd done it....knowing kawi, they may have changed them at some point. I'll try on one of mine seeing as how I have two and neither of them is going back on.
I only need to keep one in the unlikely event I sell one and feel like giving it to the new owner.

I'll let you guys know what happens. :)

Dave
 
1 - 20 of 50 Posts
Top