Carb problems - Kawasaki KLR 650 Forum
2008+ KLR650 Wrenching & Mod Questions For repair, maintaining or modifying discussions related to the newly updated 2008 and beyond, Generation 2 KLR650 Motorcycle.

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post #1 of 24 Old 04-10-2011, 05:54 PM Thread Starter
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Carb problems

During maintenance on my 08' I decided to clean the carb, at the time this seemed like a bright idea. While cleaning it, I decided I should put in a jet kit, this also seemed like a bright idea. So i ordered the kit and a week later it was time to put the carb back together again.

Now here is some don'ts for those of you who want to clean your carb.
1. Don't clean it unless you have a parts schematic so you know where everything goes.
2. Especially don't use compressed air if you don't have the above mentioned! (guess how i know this)

So I used the dynojet kit, did it to their manual, used their 138 jet, clipped their needle on the seccond spot from the top, and drilled out the slide with their drill (opinions on this please), and set the mixture to 2.5 turns out. I have a no-toil air filter, drilled out muffler (1.75" hole drill to the back i think it was). And otherwise nothing notable yet.

I am now 99.99% positive all parts lost with compressed air are back in the carb. (needle jet, and washer and o-ring on mixture screw). Currently I'm in the progress to return everything to stock (undrill the slide) When I had it together with the dynojet stage 1 It would idle properly and run properly probably up to 4k rpms (standing still no load) But if from idle i would pin the throttle to max it would should up to 8k rpms then fall back down to 4.5 k with an annoying exhaust noise and some smoke.

Ok so i'm hoping that returning the carb to stock will bring my bike back. I've had this carb apart a good 10~15 times now. So if anyone has any opinions. give em!

Edit: Just some more background, while i ran the engine with the stage 1 i also took of the airbox door and tried without the filter to see if it was an intake problem with the same results.

Last edited by xjdubber; 04-10-2011 at 06:03 PM.
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post #2 of 24 Old 04-10-2011, 07:46 PM
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Sounds like you may have a DIAPHRAGM AIR LEAK, possible when the diaphragm isn't seated correctly in its groove . . .

While I'm not a consummate fan of jet kits, nothing in the kit should produce the symptoms you describe; the jet kit remains, in my view, not inconsistent with the, "First, do no harm" tenet of the motorcycle tinkerer's oath.

Adjust and reassemble carefully; you should be good to go.

Excellent "schematics" are available at http://www.kawasaki.com , owner info, view parts diagrams; excellent photography is available from klrworld.com http://klrworld.com/forums/index.php/topic,2333.0.html ; and . . . a good treatise on the CVK40 can be found by Googling, "Care and Feeding of the CVK40." http://www.gadgetjq.com/keihin_carb.htm

Do not despair.

-----------------

You ask specifically about drilling the slide; enlarging the vacuum port to 7/64" diameter appears rather benign, to me; may improve throttle response, but . . . not culpable for your problems, IMHO. Wouldn't JB Weld the hole and re-drill myself; I'd hold what I've got in this department, if I were in your place.

Last edited by Damocles; 04-10-2011 at 08:32 PM.
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post #3 of 24 Old 04-10-2011, 08:35 PM
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Hey, xjdubber!

I just added some links by editing my above post (bet you kick yourself for the absence of The Patman's illustrated carb guide (http://klrworld.com/forums/index.php/topic,2333.0.html) before you started!).
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post #4 of 24 Old 04-10-2011, 10:37 PM
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xjdubber-
not sure if this helps with your carb problem, but I just installed a JD needle/jet kit and used his recommendations of a 160 main with the needle set in 2nd from top position (also drilled the slide). Runs very well and noticeably stronger than stock. I opened airbox as well, but did not mod the exhaust.

PPMC #4
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post #5 of 24 Old 04-10-2011, 10:40 PM Thread Starter
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Quote:
Originally Posted by Damocles View Post

You ask specifically about drilling the slide; enlarging the vacuum port to 7/64" diameter appears rather benign, to me; may improve throttle response, but . . . not culpable for your problems, IMHO. Wouldn't JB Weld the hole and re-drill myself; I'd hold what I've got in this department, if I were in your place.

I've just checked the diaphram thorougly no holes or tears in the rubber, when i put her back together ill use some silicone grease on the sealing edges to get a better seal that way, the drill supplied with the jd jet kit is bigger than 7/64 close to 1/8 actually. that is why i am going trough the jb weld process. it just about dry right now might give things another try tonight. I guess the other thing could be the choke circuit not sealing of correctly. Right now i have the cable adjusted as far out as it will go, so it should not be a problem but you never now.

PS: Despair set in long ago
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post #6 of 24 Old 04-10-2011, 10:50 PM Thread Starter
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Quote:
Originally Posted by KLR-zin View Post
xjdubber-
not sure if this helps with your carb problem, but I just installed a JD needle/jet kit and used his recommendations of a 160 main with the needle set in 2nd from top position (also drilled the slide). Runs very well and noticeably stronger than stock. I opened airbox as well, but did not mod the exhaust.
DJ and JD to diffrent kits, I wish i would have known about the JD kit, it has a much nicer needle and uses stock keihin jets. The Dynojet Kit does not.
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post #7 of 24 Old 04-10-2011, 11:25 PM
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Are you absolutely sure that all three pieces in the top of this photo (which I pirated from Redondo Ron) went back in? Especially the collar, which falls out when you're not looking and rolls under the workbench?



The collar is certainly launchable with compressed air...

T

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post #8 of 24 Old 04-10-2011, 11:37 PM Thread Starter
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Quote:
Originally Posted by Tom Schmitz View Post
Are you absolutely sure that all three pieces in the top of this photo (which I pirated from Redondo Ron) went back in? Especially the collar, which falls out when you're not looking and rolls under the workbench?


The collar is certainly launchable with compressed air...

T
It is definitely launchable with air! The little o ring and washer on the mixture needle as well! Managed to find them back though.

Just put it back together epox'ed the hole and tried to drill it out smaller but I just pushed the epoxy out with the drill. She runs better, I'll have to take it for a drive tommorow. Still when i blip the throttle she rev's to 8k then dips to 5k. Do these things have rev limiters, that could cause that i guess. Tommorws drive will tell.
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post #9 of 24 Old 04-11-2011, 12:05 AM
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As far as I know, the only rev limiter is valve float :^)

T
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Tom [email protected]

ďThe muzzle of the Luger looked like the mouth of the Second Street tunnel, but I didnít move. Not being bullet proof is an idea I had had to get used to.Ē -Philip Marlowe

ď'Why' and 'How' are words so important they cannot be too often used.Ē -Napoleon Bonaparte

Sting like a butterfly.
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post #10 of 24 Old 04-11-2011, 12:49 AM
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Your bike, xjdubber, but . . . re-doing your slide drilling, to me, is a waste of JB Weld.

Our Harley bretheren drill their slides to 1/8" all the time on their similar Keihin CV40 carburetors; the vacuum port only facilitates low-pressure transfer above the diaphragm, can't see how drilling it even to 1/8" diameter could produce your symptoms.

Like Tom Schmitz, I've always thought the "rev limiter" on a KLR650 was the valvetrain only!

I think you have a systemic problem, your carb isn't mixing air and fuel correctly at higher mid-throttle operation; here's hoping you find its cause and cure.

As to the diaphragm installation, some use Vaseline or the like to help hold the squishy thing in its groove; I've found it an elusive little beast, myself!
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