Carb, Jetting, Fuel mix. Doggy 1st gear.

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morganid
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by morganid »

So as I've said on other posts, I've recently got an 2003 KDX 220. Love the bike but it doesn't seem to have much bottom end below the power band in 1st gear. The previous owner mixed the fuel fairly rich. I think he said it was 30:1. I don't see much oil leaking out of the exhaust pipe. There is a black ring and I can see on my tail light an oily film. (I mounted a RMATVMC taillight underneath the stock fender so it is RIGHT next to the exhaust.) I ride it back and forth to work at 4.800 ft elevation. I make a conscious effort to get in and out of the power band frequently to clear the un-burned oil since the bike tends to stay cold (it is winter after all).

I climbed my first hill on the bike today. It was way fun, but it was doggy in first gear. I would have to slip the clutch to get the bike into the power band. Once I was in it and on to 2nd gear, it was great. The bike was warm by this point. How can I tell if my bike needs more or less oil in the fuel? How can I tell if it needs to be re-jetted?

I've been hesitant to ask because I'm coming from a 2000 KX 500. (I started riding that bike when I was 14, and have ridden it for the last 8 years) The KX500 was such a massive motor that when I was climbing I could literally drop the rpms to just above idle and romp on it and get back up to speed. The KDX obviously won't be like that so I'm not exactly sure what it is supposed to feel like.

Thanks!
Piet
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by Piet »

Not an expert but went through the same thing.

Investigate if the KIPS power valve is working. Open the slotted cover on the left hand side and rev the bike to see if it is turning.
You can also go a step further and remove the exhaust and look into exhaust port while turning the shaft above with a 10mm socket to see if it is working.

Second I would look at the needle and jetting numbers. If they are far off from the below recommendations then start from scratch.

Borrowed from another site:

1995 to 2003 KDX200

Stock -Run the stock R1174K jet needle in the second from the top clip position, 45 pilot jet, 155 main jet and fine-tune the pilot circuit using the air screw.

With a performance pipe/expansion chamber, the air box lid removed and the stock or a performance silencer run a 42/45 pilot, R1174K jet needle in the mid clip position, a 152/155 main jet fine tune the pilot circuit using the air screw.

1997 to 2003 KDX220

Stock run a 42 pilot jet,the stock R1173L jet needle in the second from the top clip position, a 142/145 main jet and fine tune the pilot circuit using the air screw.

With a performance pipe/expansion chamber, air box mods , the factory or after-market silencer and the stock 33mm carburetor run a 42 pilot, the stock R1173L jet needle in the second from the top clip position, a 145/148 main jet and fine tune the pilot circuit using the air screw.

Same as above but with your carburetor bored between 35 and 36mm or running a 1988 to 2003 KDX200 35mm carb jet according to 95 to 2003 KDX200 requirements.
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scheckaet
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by scheckaet »

jet your carb the proper way. check my sig for how to.
the number posted above MIGHT get you in the ballpark but don't take them as the eterenal truth, not 2 bikes are equal. :wink:
Pick an mix ratio (most use 1:40) and JET for it. Changing mix ratio to "fix" a jetting problem is not the answer and won't get you anywhere...but give you a headache.
morganid
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by morganid »

scheckaet wrote:check my sig for how to.
Wat do you mean, "sig" ?
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scheckaet
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Re: Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by scheckaet »

signature at the bottom of the message, check the links: jetting guide and newb info :wink:
morganid
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Re: Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by morganid »

Ah. I see. Thanks. My wife is out odd town for the weekend. Hopefully I'll be able to dig deeper into this this weekend.
Piet
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by Piet »

scheckaet wrote:jet your carb the proper way. check my sig for how to.
the number posted above MIGHT get you in the ballpark but don't take them as the eterenal truth, not 2 bikes are equal. :wink:
Sorry, what I tried to say is yes you need to to jet the carb properly. But if you open the carb and the numbers are not in the ballpark then don't ignore the fact that the previous owner might have tried to fix another problem by jetting way out.
motogoalie1
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Carb, Jetting, Fuel mix. Doggy 1st gear.

Post by motogoalie1 »

So I dont like wasting time.

I love jetting database to get in the ball park on jetting. Then you can use some jetting guide on the internet to fine tune a bike.

theres a good jetting database on thumpertalk that will get you in the ballpark for altitude.
what you need to do at some point is settle on one type of 2 stroke oil, one type of sensible oil to gas ratio. And at some point doma topend to make sure your motor is ok.
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