Worn out carb?

Discussion specific to the 1989 - 1994 (E Series) KDX200 model sold in the USA
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90SDKDX
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Worn out carb?

Post by 90SDKDX »

Hey Everyone. So I had an on going post about a no start issue I was dealing with
Posts here: http://www.kdxrider.net/forums/viewtopi ... 15&t=22260
and here: http://www.kdxrider.net/forums/viewtopi ... 15&t=21762

Here is where I stand now. The bike starts and runs. It starts easily and is not kicking back as I had experienced before. Honestly, I don't know what I did to fix this issue, other than swapping my old electrical components back in.

Anyways, the last couple weeks I've been trying to jet the bike. It rides fine, but once in WOT and the motor is hot, it bucks and bogs out, and if WOT long enough, will stall out. Pull the plug after any run and the insulator is black.Choking the bike makes it worse. I started with a 152 main and have gone all the way down to a 140. Still rich. I can't remember what pilot size I have now but I've got the 1173 needle in position # 2 (from the top). Float height is correct. Brand new dual stage Boyesen reeds and new intake manifold. New twin air filter. New carb jet block gasket .Air box lid is installed with three holes punched in top (was this way when I bought it). Full FMF pipe and FMF spark arrestor muffler. 150 PSI compression.

I was starting to think that my transmission side seal was blown, but I don't seem to be losing any tranny fluid. It also doesn't seem to be smoking any more than it has in the past. I seem to be seeing quite a few posts of people scraping their old carbs and putting a new unit in. It does make some sense, as this machine is 28 years old now, so I'm sure there is some wear inside.

Can anyone tell me if I'm making sense? I don't know of anything else that would cause the bike to continually rich. For reference I'm jetting at close to 4000' and ride up to about 6000'.
jjavaman
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Re: Worn out carb?

Post by jjavaman »

Mine did that once after a long hot ride, it was a dirty air filter. Do you maybe have too much oil in the filter?
97-220 with a PC pipe. 2015- RB carb and head mod
90SDKDX
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Re: Worn out carb?

Post by 90SDKDX »

Air filter is lightly oiled right now.
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SS109
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Worn out carb?

Post by SS109 »

Have you done a leak down test yet?
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Re: Worn out carb?

Post by KDXGarage »

Time for a pressure test and a vacuum test.
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Re: Worn out carb?

Post by Chilly »

Did you clean your carb with cleaner? My bike was leaking gas out of the over flow just sitting in my garage. I didnt have any cleaner at the house so I used air. Looked clean but wasn’t. Bike run like hell after that. Went and bought some carb cleaner this time and it straightened right up. So if you didn’t use carb cleaner I’d do that first before buying a new carb.
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Re: Worn out carb?

Post by KDXGarage »

As always, Jet block gasket OK?
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90SDKDX
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Worn out carb?

Post by 90SDKDX »

To respond to everyone,

No I have not done a leak down test.
I have dipped and cleaned the carb, and installed a brand new jet block gasket.
I'm sure that a leak down test is in order. If that doesn't show any leaks, then maybe a carb will be needed.
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Worn out carb?

Post by SS109 »

Yeah, a leak down test is a lot cheaper than a new carb!
Youtube Channel: WildAzzRacing
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Current KDX: '98 KDX220
Old KDX: '90 KDX200 -White/Blue
'11 GasGas EC250R
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