KLX install no power at half throttle and up - Kawasaki KLR 650 Forum
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post #1 of 6 Old 11-03-2019, 03:11 PM Thread Starter
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Join Date: Apr 2019
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KLX install no power at half throttle and up

Looking for a little experience as I pull the carb again. Just installed the KLX needle in my 2017. Went with 140 main, 42 pilot, 3rd clip/no shim under (to richen a little for the extra air). Has a UNI filter, snorkel removed, stock exhaust. The rest of the engine is stock. On the test ride, idle up to a 1/3 or 3/5 throttle runs great. After that, the power literally just drops off and the revs barely climb. No power at all from 1/2 throttle up to full open. Maintains speed and sounds fine, but won't accelerate past about 55 mph. No decel pop, nothing weird sounding at all, temp lower than before the KLX needle and at about 1/4 up the gauge.

Even if the 140 is slightly lean for the extra air intake, I wouldn't think it would have such a drastic effect.

I'll take a close look at the diaphragm but it was fine yesterday. Thinking the 142.5 main, 2nd clip on the needle - Unless... anything I need to look for that I could have botched that would cause it to stop revving at about 4000 rpm? I'm comfortable with working on carbs - done plenty but, "you don't know what you don't know."

Last edited by atomhart; 11-03-2019 at 03:17 PM.
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post #2 of 6 Old 11-03-2019, 05:19 PM Thread Starter
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To follow up for future reference

Dropped the needle from #3 to #2, no shim. Swapped out the 140 main to a 142.5 main. Kept the 42 pilot. 2 turns out on the air screw. Runs perfect now. Apparently a 140 main starves the engine enough (mine anyway) to completely kill the power at half throttle and up. I had thought with a UNI filter and no snorkel, but stock exhaust, the airflow was close enough to stock to run the 140.
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post #3 of 6 Old 11-05-2019, 11:18 AM
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I didnt' see your post before but the jetting you are running now is exactly what I would have recommended. the airbox is a far bigger bottleneck than the stock exhaust and the effect on airflow is much more substantive on the intake side. That said, I would have guessed a pinched/holed diaphragm or other installation error based on your first post. Oh well, if it's working now, that's all that matters.

Cheers,
Dave
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post #4 of 6 Old 11-05-2019, 11:34 AM
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I was also going to suggest an error on the re-installation of the diaphragm into its groove. Jetting would not prevent revving, just slower increase.

I would have also inquired if this was an Australian Learner Approved Model (LAM), with 2 vacuum vent holes below the white plastic diaphragm assembly parts, but your 2nd posting confirms it is not.

Ride On.

pdwestman
Modify at "YOUR OWN RISK"!

Still riding my 1987 KL650-A1. 85,000+ miles & counting
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post #5 of 6 Old 11-05-2019, 05:32 PM Thread Starter
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Dave, you would've been spot on. I didn't think one size lean on the main would cause such a drastic effect, especially when a 140 is recommended for a stock bike.

Pd, I wasn't ruling that out since it was the most likely cause I could come up with, but everything looked good inside. Interested to see how far the mpg drop now.
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post #6 of 6 Old 11-05-2019, 06:10 PM
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Quote:
Originally Posted by atomhart View Post
Interested to see how far the mpg drop now.
Probably a couple but rest easy knowing that running the bike overly lean just to gain a couple mpg's isn't a great idea anyhow.

Cheers,
Dave
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