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I got a question. I own a 2016 KX 85. It ran AMAZING after it first bought it used and was in beautiful condition and I picked it up for only 2500. I was riding when all of a sudden it started bogging down right before the power band.i don’t think it’s jetting because the bogging just turned on like a switch and it was running perfect before it. The bike was like that for a month.                                               Apparently the previous owner never oiled the filter so it was dry as a rock and  was falling apart and got sucked into to the intake so I’m guessing my power valve is gummed up or stuck close or open. I was riding one day with the bog issue and about 35 minutes of riding I shut it off to take a break. Came back 20 minutes later and it would not start.I changed the spark plug, cleaned out the carb,checked the reeds,and tried hill starting it but nothing.           When ever I try to hill start it I can hear it trying to crank and It starts for like half a second but then dies.I don’t remember if I left the fuel petcock on but what I’m guessing is that I flooded the engine and tried starting which messed up my electronics.The reason why I think I flooded the Engine is because when I took off the reeds the intake manifold and reed were soaked in gas.I heard that starting the engine while flooded can mess with a woodruff key or your CDI or something. There is spark coming from the plug though.And yes I mix the gas with oil at 32:1 cause I’m in the pipe all the time.This is my first time owning a 2 stroke.Any answers or tips.

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There's a good chance you'll need to rebuild the top end if it was run with a dry filter for a prolonged time.  You said the filter fell apart and got sucked in.  Start by removing the carb and the reed cage.  Clean both and make sure the reeds aren't cracked or damaged.  Put it back together and see what happens.  

 

The filter is on you.  It doesn't matter if it's a 2t or a 4 stroke.  That is one of the main areas of maintenance on a bike.  You need to check it all the time, clean and oil after every ride or two.  Did you change the trans oil since you bought the bike?  Have you checked the coolant level?

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5 minutes ago, CMJ said:

There's a good chance you'll need to rebuild the top end if it was run with a dry filter for a prolonged time.  You said the filter fell apart and got sucked in.  Start by removing the carb and the reed cage.  Clean both and make sure the reeds aren't cracked or damaged.  Put it back together and see what happens.  

 

The filter is on you.  It doesn't matter if it's a 2t or a 4 stroke.  That is one of the main areas of maintenance on a bike.  You need to check it all the time, clean and oil after every ride or two.  Did you change the trans oil since you bought the bike?  Have you checked the coolant level?

I already cleaned the carb, looked at the reeds and changed and oiled the filter.i also changed the trans oil and checked the coolant level.There was no light coming through the reeds which is good. I decided to take a look at the piston yesterday and I saw some blow-by.Is blow-by enough to stop the bike from starting. Like I said I tried hill starting like 50 times but still no start.

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4 minutes ago, Monsour Saleh said:

I already cleaned the carb, looked at the reeds and changed and oiled the filter.i also changed the trans oil and checked the coolant level.There was no light coming through the reeds which is good. I decided to take a look at the piston yesterday and I saw some blow-by.Is blow-by enough to stop the bike from starting. Like I said I tried hill starting like 50 times but still no start.

if you have the top end apart alr send pictures of it

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20 minutes ago, Triple Nine Motorsports said:

if you have the top end apart alr send pictures of it

I didn’t have time to take the cylinder off but I looked at the sides of the piston in the third picture through the exhaust port and there is blow-by.Its hard to see on camera but trust me there is.7C490A9A-E222-42F7-A545-7D0B1282F7B4.thumb.jpeg.45d648d0cf9d15e4966aa92dcb247d59.jpeg4BC1DB29-1F1E-4195-A696-9703FF43D4AB.thumb.jpeg.12683f55db468349ec907550f694150b.jpeg4E2DBFE5-F393-49B0-9B19-BDA8CB89A4B2.jpeg.b5069a2d2997ca33378d13f79d761250.jpeg

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Just now, Monsour Saleh said:

I didn’t have time to take the cylinder off but I looked at the sides of the piston in the third picture through the exhaust port and there is blow-by.Its hard to see on camera but trust me there is.7C490A9A-E222-42F7-A545-7D0B1282F7B4.thumb.jpeg.45d648d0cf9d15e4966aa92dcb247d59.jpeg4BC1DB29-1F1E-4195-A696-9703FF43D4AB.thumb.jpeg.12683f55db468349ec907550f694150b.jpeg4E2DBFE5-F393-49B0-9B19-BDA8CB89A4B2.jpeg.b5069a2d2997ca33378d13f79d761250.jpeg

Thats A LOT of carbon caked up on the exhaust bridge. I would recommend taking the cylinder off and inspect a possibly put a new top end or atleast new rings

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Yeah, take off the cylinder.  Hopefully it's nice and smooth, then you just need rings.  Since you don't know the history of the bike you might as well replace the piston too.

 

Did you confirm you have spark?

Edited by CMJ

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8 minutes ago, CMJ said:

Yeah, take off the cylinder.  Hopefully it's nice and smooth, then you just need rings.  Since you don't know the history of the bike you might as well replace the piston too.

 

Did you confirm you have spark?

There is spark coming from the plug.if I change the rings and piston and it still won’t start then can it be my spark timing?

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14 minutes ago, Monsour Saleh said:

There is spark coming from the plug.if I change the rings and piston and it still won’t start then can it be my spark timing?

its just 4 more bolts to take the cylinder off. Once you properly inspect/measure stuff on the top end there isnt going to be any reason its not going to run since you have good spark already.

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3 minutes ago, Triple Nine Motorsports said:

its just 4 more bolts to take the cylinder off. Once you properly inspect/measure stuff on the top end there isnt going to be any reason its not going to run since you have good spark already.

Also before it wouldn’t start the bike would run great when all of a sudden it started bogging right before the powerband and at random rpms. I don’t think it’s my jetting because the bogging just started all of a sudden.could it be my power valve started gumming up and got stuck.Thanks for all of the help and support 

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33 minutes ago, Monsour Saleh said:

Also before it wouldn’t start the bike would run great when all of a sudden it started bogging right before the powerband and at random rpms. I don’t think it’s my jetting because the bogging just started all of a sudden.could it be my power valve started gumming up and got stuck.Thanks for all of the help and support 

Yes im pretty sure its the power valve gumming up since you said the filter was falling apart and the exhaust bridge has so much carbon

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Just now, Triple Nine Motorsports said:

Yes im pretty sure its the power valve gumming up since you said the filter was falling apart and the exhaust bridge has so much carbon

Thank you so much for all of the help. I didn’t know what to do until now.

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On 9/21/2020 at 11:18 AM, Monsour Saleh said:

Thank you so much for all of the help. I didn’t know what to do until now.

0A903EE5-AE1C-43CA-AA1D-001666960314.thumb.jpeg.d2d848c8ac0a36521992298abeb4461b.jpeg418B5D4D-2E5D-445A-B6E3-2EFD02FA9574.thumb.jpeg.7911b951b4829fa8ef3fa73f39e927be.jpegTook the cylinder off and there appears to be minor scarring/scoring .There are other marks but this is the only one I could get a good pic of. Overall the cylinder looks beautiful except for the marks.The previous owner said he only had 19 hours on it.Obviously he was lying. My piston and rings are down to shit. My power-valve moves up and down smoothly. My crank Bearings feels smooth and solid.I can’t tell if I need to buy a new cylinder or if this one is still in decent condition from the marks. I can barely feel some of them with my finger nails.They aren't big marks like in some other pics but still.

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