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Discussion Starter · #1 ·
I noticed after I adjusted my valves last week that my 2018 KLR started making popping noises on deceleration. I bought the bike (in January 2021) with 11,000 kms on it and it's now sitting at 14k.
I've checked the exhaust shield screws, the exhaust manifold 12mm bolts, everything was tight.

Is this normal for the KLR? It's intermittent, happens probably 30% of the time while I decelerate and mostly in 2nd or 3rd gear. And yes I made sure the choke is off, the sparkplug is brand new and the airfilter has just been cleaned.

Would the 22cent mod help fix this? Or should I mess around with the fuel mixture screw (the one you have to drill the carb to access)
 

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Valve tappet re-adjustment doesn't cause an engine to run any leaner or richer, imo.
Exhaust system after-fire doesn't necessarily mean lean burn either. Aftermarket mufflers don't dampen the popping as well as the oem muffler.

Did you reinstall all of the spaghetti of the AIS system properly or did you install an AIS block-off kit complete with o-ring seal?

Maybe hold a feather or piece of paper near the header pipe flange and then touch the starter button to check for a good gasket.
 

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Discussion Starter · #3 ·
Valve tappet re-adjustment doesn't cause an engine to run any leaner or richer, imo.
Exhaust system after-fire doesn't necessarily mean lean burn either. Aftermarket mufflers don't dampen the popping as well as the oem muffler.

Did you reinstall all of the spaghetti of the AIS system properly or did you install an AIS block-off kit complete with o-ring seal?

Maybe hold a feather or piece of paper near the header pipe flange and then touch the starter button to check for a good gasket.
I didn't mess with the AIS system. I just followed the steps online and in the klymer manual for valve adjustment. Reconnected everything the way it was.

i'll test out the feather method, hopefully it's a bad gasket
 

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lean comes from the carb and comes set like that from the factory for emissions.

the popping is the AIS introducing air under vacuum (off throttle) to the exhaust. again for emissions by helping burn any unburned fuel.
 

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Discussion Starter · #5 ·
lean comes from the carb and comes set like that from the factory for emissions.

the popping is the AIS introducing air under vacuum (off throttle) to the exhaust. again for emissions by helping burn any unburned fuel.
I'm thinking it's the exhaust manifold gasket leaking. I'm getting terrible MPG while on the highway 38MPG. While out on gravel and keeping it below 4.5k RPM I get 45 MPG. Before I used to get 48-50.

Can a leaking exhaust manifold cause poor MPG? I hit reserve at 250km (155) yesterday all highway driving. Usually I can go at least 320kms (200 miles) on primary before I have to switch to reserve.
 

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Fuel mileage is dependent on carburetor float height & jetting. Valve clearance & exhaust system really shouldn't effect fuel mileage.

Maybe your carburetor has a slight flooding issue? Making it run rich.
The North American KLR carbs DO NOT have an overflow stand pipe inside the float bowl, so they can't drip out of the bottom drain nipple, as it is Only a Drain Nipple.

Have you been inside of your carb at all?

Is your drive chain adjusted too snug? Does it have slack when you set on the bike? Are your tire pressures near 32 psi Front / 30 psi Rear?
 

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Discussion Starter · #7 ·
Fuel mileage is dependent on carburetor float height & jetting. Valve clearance & exhaust system really shouldn't effect fuel mileage.

Maybe your carburetor has a slight flooding issue? Making it run rich.
The North American KLR carbs DO NOT have an overflow stand pipe inside the float bowl, so they can't drip out of the bottom drain nipple, as it is Only a Drain Nipple.

Have you been inside of your carb at all?

Is your drive chain adjusted too snug? Does it have slack when you set on the bike? Are your tire pressures near 32 psi Front / 30 psi Rear?
Not yet. Should I? An exhaust manifold gasket is 20 bucks, should I just take that down first and check the gasket before messing with the carb?

Is your drive chain adjusted too snug?
No, it's in spec
Are your tire pressures near 32 psi Front / 30 psi Rear?
Tire pressures are at the owner manual specs (21 PSI front - 28 back)
 

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Exhaust Gasket $6 +shipping. Go through and grab other parts you might need while you’re at it. Just adjust the model year to yours if you browse other parts. Exhaust gasket will be the same Gen 1/2.

Kawasaki says a lot of things that aren’t quite accurate, at least anymore. Run higher psi, as Paul lists, and have 2psi higher in front. Especially if you have stock springs, higher front psi will help with weight transfer.
 

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cedar-leaf,
An air tight / water tight exhaust gasket is always a good thing.

Is your air filter properly cleaned and Re-Oiled? Is there a mouse nest or food store inside of the air box restricting air flow?
I once found an air box Completely full of dog food!

Can you confirm with a helper that your drive chain has at least 1/2" of slack with all of your weight on the bike?
I find the factory way of measuring chain slack to be a little mis-leading.
Normally we want the lower run of the chain to be able to 'just touch' the rear tip of the rubber underslider of the swingarm when gently lifting the lower run up with the rear shock topped out.

And please try 30 psi in your front tire. You can retain 28 psi in the rear. The bike will handle better on asphalt & the front tire will scallop less. And the tire will have less rolling resistance.
 

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I had a similar issue. Found that my "choke" wasn't fully closing.
 
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