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KX85 Jetting Chart


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jslew,

Here’s the chart I put together for your wife’s 02 KX85. This should give you a good head start towards sorting the jetting out. Start with the airscrew @ 1-1/4 turn out from fully seated and you will be within 3/8 of a turn + or – of the ideal setting. 👍

2002KX85Jetting.jpg

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that is awesome as we run a kx85 and kx100,

this helps a bunch and the current jetting we are using is only 1 off from your chart, but we have lots of mods done :worthy: this will be a great resource to us, and im sure many others thank you so much:thumbsup:

You’re very welcome. I’m happy the information can help a few folks out. 👍

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  • 1 year later...

I am assuming that the jet settings for a KX65 would be close to the KX85? Based on other threads it looks real close. I have just recently moved from sea level to Colorado Springs (6,700ft) so I am looking for a starting point. Going through the whole bike to make sure everything else is on the up and up first i.e. cyl pressure... (although I can only check the cold cyl pressure now. lol)

BTW any one ever check the cyl pressure cold? I am getting about 110 psi and I know the manual says between 90 and 170 after warm up is OK. This would lead me to believe that the pressure would rise aprox 20 psi after warm. New here so if someone knows a more appropriate thread for this pls let me know..

Thanks RIN

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  • 3 weeks later...

Hi Vet as an oldtimer @ 44 riding the bikes all my life road and dirt, I found your information very helpful. I even took the time to join to reply. Kawa down the road could not help me. I purchased the kx 80 at a good price in the belief it needed jetting going by your chart I am bang on. Hopefully my son will have a good reliable bike to ride as the engine has already has been rebuilt with reciepts. It is currently running 138 main and a 55 pilot belief it or not. No wonder it wets plugs up after short periods off the tap. Thanks again for your thread. Perth Western Australia.

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On 4/27/2021 at 5:45 PM, eric wesche (skippy622) said:

You can download a free copy of the owner manual on line. It has the chart in it.  As long as it close in the year of the bike you will be good since kx 85/100 have not changed much year to year.

I have a manual for my bike and have tried multiple different jetting combos from pro circuit jetting specs to others I have found on here. But I am still having issues with my daughters 08 KX85. It has FMF exhaust with a FMF shorty and v-force reeds no additional motor work. The carb is clean and freshly rebuilt, right now it has a 140 main 45 pilot and NAPE on the 3rd clip from the top and air screw is 1.5 out. Running 32:1 non-ethanol 93 pump gas. I live in Florida so I am at or just above sea level most of the time with temps ranging from 50 to 100 degrees. The bike is extremely hard to start initially (10 or more kicks with choke on), but once it starts it is fine until you get into the upper RPMs then it will bog like it is starving for fuel. The bike is still new to me but I put a fresh top end into it 4 hrs ago (when i first got the bike) along with new plug and new air filter. Any suggestion on a way to head to try and remedy my issue?

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12 minutes ago, rojo_143 said:

 

I have a manual for my bike and have tried multiple different jetting combos from pro circuit jetting specs to others I have found on here. But I am still having issues with my daughters 08 KX85. It has FMF exhaust with a FMF shorty and v-force reeds no additional motor work. The carb is clean and freshly rebuilt, right now it has a 140 main 45 pilot and NAPE on the 3rd clip from the top and air screw is 1.5 out. Running 32:1 non-ethanol 93 pump gas. I live in Florida so I am at or just above sea level most of the time with temps ranging from 50 to 100 degrees. The bike is extremely hard to start initially (10 or more kicks with choke on), but once it starts it is fine until you get into the upper RPMs then it will bog like it is starving for fuel. The bike is still new to me but I put a fresh top end into it 4 hrs ago (when i first got the bike) along with new plug and new air filter. Any suggestion on a way to head to try and remedy my issue?

45 slow jet?  I don't even see that recommend. Try a  38

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7 minutes ago, eric wesche (skippy622) said:

45 slow jet?  I don't even see that recommend. Try a  38

Here is a picture of the online manual that I am using from 09 covering my duaguters bike. The stock jetting in the manual is what I am currently at. I will try the 38 as ypu suggested and report back.

Screenshot_20210511-141034_OneDrive.jpg

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Cylinder looked fine no worn coating, flaking or scratches. The bike runs fine once started until in the higher rpms where it bogs down but as soon as you let off the gas it livens right back up. This carb is just a little harder to fine tune than my YZ250. I will be doing a compression test and a leak down test on the bike in the coming weeks to ensure those are not the cause of my problems. 

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