1996 KDX200 jets

[ff154]

Please don't beat me up because of this question. I used the search function and came up with two different answers. What is the stock jetting for my bike (1996 KDX200) I have read 160/48 and 155/45. I have the 160/48 combination in the carb right now, and it's too rich. 32:1 mixture. I have jets on order, but I was planning on just running 40:1 before I go switching jets around. Thoughts? Help? Thanks in advance.

Scott

 

[reepicheep]

What reeds, airbox setup, and exhaust setup are you running?

 

[julien_d]

Switching to 40:1 will make it richer. A 40:1 mixture contains more fuel than a 32:1 mixture. Changing oil ratio's is not the answer. If you want to run 40:1 for some other reason, then that's fine, but you'll still need to re-jet.

Stock jetting was probably 160/48, and yes, that's way rich.

 

[ff154]

Thank you all for your timely replies. I am sorry I did not specify that the bike is all stock. Stock pipe, airbox, and reeds. By a "leaner" mixture, I was referring to reducing the amount of oil in the fuel. The plug I took out of it was oily and black (not to mention large amounts of exhaust smoke while running), thus leading me to believe that it's too rich in terms of not only fuel delivery, but the mixture as well. I understand that worn reeds could possibly mimic rich conditions (and that is on my list of items to check), but you all confirmed what I thought about how the carb is jetted. Thank you. I'm sure I will be posting more questions as I get more familiar with the bike.

Scott

 

[reepicheep]

45 is probably close to right on the slow jet, and even if it isn't, you can dial it either way a little with the air fuel mixture and the needle clip position.

That 155 main still sounds rich for stock intake and exhaust. Common wisdom is to pull the snorkel and leave the airbox lid. With that and a stock exhaust, you might end up needing a main that is as small as a 148.

To have it spot on, you will need to rejet based on temperature, it can change by as much as 5 sizes between cool fall days and hot summer days.

I'll try and remember to check my notes (at home) later tonight. I've fussed with jetting of a 225 Eric Gorr big bore kit with FMF Torque, a stock 220 with VForce and pro circuit rev pipe, and a bone stock 200. Most are now close, none are perfect, and the stock 200 is still a bit off (but pretty close). I have notes on it somewhere...

 

[ff154]

Thank you for your input. I understand that this (tuning) is an evolving process and no two bikes are the same, but your input is very helpful. I will be posting results as changes are made.

Thank you for the tip about the snorkel. I will try that as well.

Scott

 

[reepicheep]

Here is a nice succinct summary...

http://www.shopfrpoffroad.com/aboutus.htm

Not the only opinion, but a well respected one.

 

[ff154]

Thank you again. I wil definately give that website a look.

Scott

 

[julien_d]

Thank you all for your timely replies. I am sorry I did not specify that the bike is all stock. Stock pipe, airbox, and reeds. By a "leaner" mixture, I was referring to reducing the amount of oil in the fuel. The plug I took out of it was oily and black (not to mention large amounts of exhaust smoke while running), thus leading me to believe that it's too rich in terms of not only fuel delivery, but the mixture as well. I understand that worn reeds could possibly mimic rich conditions (and that is on my list of items to check), but you all confirmed what I thought about how the carb is jetted. Thank you. I'm sure I will be posting more questions as I get more familiar with the bike.

Scott

Just forget about all that right now. Lean/Rich does not relate to the amount of oil in your mix, aside from running more oil makes the bike run leaner, and less oil makes the bike run richer given the same jetting.

rich/lean condition is the result of air/fuel mixture, not oil/fuel ratio. Pick your oil ratio and stick to it, and THEN jet the bike. If the plug is oily and black it's because all the fuel mix is not getting burned properly due to overly fat jetting. Get yourself a range of jets and jet that thing!

I think 155/45 would be a good (safe) baseline for you to start with. FWIW I am currently running 150/42 1173n needle in 3rd clip position, 3,500 - 4,000' and temps about 40 - 50f. Bike runs like a scalded dog!

Like Reepi said, temp and altitude do make a big difference. You have to take this into account especially when looking at someone else's jetting. I'm not so sure about 5 steps between fall and summer though. It takes 2 pilot sizes, 3 main sizes and one clip position change to account perfectly for a 75 degree temp difference in my current setup (I just checked it!). 5 steps would be a massive change!

 

[ff154]

Very helpful information! I have resolved myself to get the bike jetted like I know how. I have messed with enough bikes (some with 4 carbs) to understand how it all SHOULD work (nothing is absolute of course). I will be posting results of how it all goes. I am learning a great deal on this site already, as well as other reading I have done. I guess I should state for the record, I live at about 338 ft above sea level. It gets pretty hot here in the summer time, so I think if I establish a good "spring temp" baseline, I will be able to work from there. I will be posting results as changes are made. Thank you again.

Scott