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KDX80 doesn't scream like it should

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it works it way up to where the power band should be then it just bogs at anything over 1/2 throttle. I've lowered the needle to the center clip it was in the highest (richest) spot then went one slot leaner. and still the same. we replaced the reeds with boyesen reeds. throughly cleaned the card ( it wasn't bad).

I'm out of fresh plugs at the moment I'm going to pick a few more up this weekend. The center clip plug was alittle dark. i didn't trust dropping the needle another slot without a plug to read.

any suggestions ? 

Thanks J 

update. 1130am. Ran the carb through the ultra sonic cleaner has 210 jet stock needle. Picked up a few more plugs. Mess with it some more after work 

Update 4pm 

needle is in the second to last slot from the top. Still bogs.

 

IMG_5369.JPG

Edited by KLeptoLee
Updated

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Dropped to a 200 jet it's better but it still bogs. Plug looked like it was a little hot, discolored 

im out of ideas. 

What should I do next? 

 

IMG_5372.JPG

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45 minutes ago, Motox367 said:

Has it ever been rebuilt do you know?  Bottom end top end? Do you have good compression?  

Yes it was rebuilt not long ago at least the top end was. When we had the head off the cylinder was nice and it has a wiseco piston in it. 

The piston was very clean when we pulled the head. The plug was black 

 

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Could have bad right side crank bearing letting trans oil in crankcase.  If you take right side case cover off you can check for play in bearing.  Old bike and crank bearing don't last forever.  Goodluck :thumbsup:

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12 hours ago, Motox367 said:

Could have bad right side crank bearing letting trans oil in crankcase.  If you take right side case cover off you can check for play in bearing.  Old bike and crank bearing don't last forever.  Goodluck :thumbsup:

Yep it's sucking in trans oil. 

Thanks

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Rebuilt the bottom end, new rod and bearings, crank bearings and seals all new trans bearings and all related seals. rebuilt the top end new rings etc 

still runs like it did before. what mix should i be running 32:1 ? 

what should i do next 

thanks J

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Still boggs?  You've been threw whole engine must be electrical. Stator ,coil. Carb is ok? Float level?  Exaust clear? Ik you said went threw Carb.  Now atleast you know its either fuel or spark problem.  In thinking Stator now maybe coil

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I’m going to pick up a few different size jets today if the shop is open. I thinks it’s to rich going to drop a few sizes .
When I was messing with it before with a leaking seal noting made a difference.

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Still boggs?  You've been threw whole engine must be electrical. Stator ,coil. Carb is ok? Float level?  Exaust clear? Ik you said went threw Carb.  Now atleast you know its either fuel or spark problem.  In thinking Stator now maybe coil


I think I have a coil floating around to try. I wonder if I can advance the timing curve a bit if that would help?

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28 minutes ago, KLeptoLee said:

 


I think I have a coil floating around to try. I wonder if I can advance the timing curve a bit if that would help?
 

 

Id line up to stock where it was should be able to tell by where screw heads were. Kdx has good point tho. Try stock jetting and go from there. If not that got to be spark problem. ,you'll get it 😀

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If you changed the jetting to try to work around a leaking crankcase seal, then you fixed the seal, now the jetting will be way off. Proper functioning seal equals a need of normal jetting.

Edited by KDXGarage

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Swapped coil no difference. Dealer says stock jet is a 210. I told the tech what was going on he said do something drastic. So I put a 170 jet in to give it a quick try. And it runs the same still bogs. Plug is soot black.

Only really runs good when I shut the gas off and it almost runs out of fuel.

Going to pull the carb apart and and check the float and needle valve.

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What brand and octane gasoline are you using?

 

What brand of oil are you mixing in with the gasoline?

 

How many ounces of oil are you mixing in with the gasoline?

 

Is the fuel fresh? How old? Any old fuel in the tank?

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What brand and octane gasoline are you using?

93 octane
 
What brand of oil are you mixing in with the gasoline?

Klotz
 
How many ounces of oil are you mixing in with the gasoline?
Mixing 40:1
Is the fuel fresh? How old? Any old fuel in the tank?
All fresh fuel.

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Deff check float level and make sure their not bent. One higher than other type thing. Check needle and slide even maybe the needle is loose or something never know ☺

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1 hour ago, KLeptoLee said:

 


120& “me 200”
A buddy is bringing me his carb off his Kdx80 to try.

 

If that makes no difference try his stator 👍👍

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