KDXRIDER.NET

So I just bought my first 2 stroke and I'm loving this kdx but I'm at a loss when taking the carb apart. It's got a 42 slow jet and a 170 main jet. Is this normal? I thought stock was 160 or so. It puts out enough smoke at wot to kill a hippie. I was thinking of putting a 158 in it and giving that a try. Thoughts?

170 sounds about right. JUST KIDDING!!

Which particular model and year KDX do you have? We can narrow it down for you.

I have a 1996 kdx200. Clip was in 4th slot.

What type of riding and what elevation?
I ride single track and fire roads at 5000 feet above sea level and run a 152 or 155.
The pilot jet sounds right.

check sig for jetting how to.
170 is really weird.

scheckaet wrote:170 is really weird.

but so is replacing it with a 158

jetting a carb is slightly more then just tossing a number out there and seeing how it runs

I ride mostly slower woods trails with occasional blasts through fields at 700-1500 feet in NC. When I bought the bike I assumed it would be plain stock so I bought a bunch of jets under 160 before I opened the carb. Would it be better to buy some in the 160's and work my way down using the jetting guide?

What pipe is on it?

What spark arrestor is on it?

Is the airbox cut, drilled or lid removed?

If it was mine, I would try the 158. What is the average temp now in NC, high 80's?

Yeah high 80's low 90's. Stock pipe, had an fmf silencer but when I went to repack it turns out the previous owner broke the perforated core and it was starting to rattle around inside so i'm putting a stock one on it. Only "mod" would be the Uni-filter and snorkel removal, everything else is stock.

assuming it's an H model, then I'd go with 158 and work from there; following the jetting guide it'll be obvious if it's close or not.

The most common reason you will find for a jet that oversize will be compensation for worn top end or major air leaks.

Thank you guys for all the help. I did run a compression test and came out to 124 psi so I know it's due for a rebuild soon, but that might take some time to happen since the wife is a few weeks away from giving birth to our first child. I'll give a try with the 158 jet once I get the bike put back together.

124 is well within specs.
makes sure there are no air leaks anywhere, inspect gaskets, cylinder, head, carb boot, inspect your reeds to make sure they are flat against the cage. clean air filter too.
make sure you got the correct plug and gap.

thank you scheckaet. It has a clean air filter installed and I'll check everything else before I start it up.

The higher the temperature is, the smaller the jets. Again, I would go with the 158 and go from there.

Do check everything is OK on that compression.