Help me pass emissions...wr400

[krust36]

Empty the tank to about 1/4 full. Add in a couple bottles of alcohol. Test. You will pass. Drain tank and add regular gas back in. No messing with jetting required.

Although if you can turn the fuel screw all the way in and the bike still runs you need to put in a smaller pilot jet.

[PoorComa]

Empty the tank to about 1/4 full. Add in a couple bottles of alcohol. Test. You will pass. Drain tank and add regular gas back in. No messing with jetting required.

Although if you can turn the fuel screw all the way in and the bike still runs you need to put in a smaller pilot jet.

Isopropyl alcohol? I would think that'd be bad in an engine since it's like 30% water.....?

Could I help lean things out by adjusting the pilot air jet out more?

[krust36]

You can buy 99% pure alcohol at the drug store.

On an FCR carb it's a fuel screw, not an air screw. So turning the screw out is more fuel which is richer. You need to turn it for less fuel which is leaner. If you can turn it all the way in and the bike still runs then the pilot jet is too big and you need to move down a size.

[PoorComa]

You can buy 99% pure alcohol at the drug store.

On an FCR carb it's a fuel screw, not an air screw. So turning the screw out is more fuel which is richer. You need to turn it for less fuel which is leaner. If you can turn it all the way in and the bike still runs then the pilot jet is too big and you need to move down a size.

I'm referring to the jet labeled as 23 in this picture . I had it all the way in at first and it didn't run and then I read I needed to have it out 7/8 so that's what I did and it runs but maybe I need to let it out more or less so it'll run better??

I know how to fuel screw works and it is all the way in, well it's just a c hair out since all the way in kills it.

[krust36]

Are you sure that you have an adjustable slow air screw? It is not a stock part on a WR400. The bike comes stock with a slow air jet which is not adjustable by turning it out/in. You have to swap in a different size jet.

There is an aftermarket slow air screw available from Sudco. See the link below for the chart to determine approximate jet size to # of turns out for the air screw if you actually have one.

http://www.sudco.com/vol33/114.pdf

[byggd]

Kurst is right. The stock adjustable screw is #24.

[PoorComa]

Are you sure that you have an adjustable slow air screw? It is not a stock part on a WR400. The bike comes stock with a slow air jet which is not adjustable by turning it out/in. You have to swap in a different size jet.

There is an aftermarket slow air screw available from Sudco. See the link below for the chart to determine approximate jet size to # of turns out for the air screw if you actually have one.

http://www.sudco.com/vol33/114.pdf

No, I'm not sure that's it's adjustable. I was assuming that it was based on the info in THIS THREAD.

[PoorComa]

Kurst is right. The stock adjustable screw is #24.

Yes, that is the Pilot Screw but I am asking about the function/effect of the Pilot Air Jet. Thanks.

[krust36]

I'm not sure what that thread is all about, but it would appear that they are talking about a non-stock carb. I would ignore it. If you really want to check your slow air jet pull it all the way out. If there is a spring behind it you have the adjustable screw. No spring then it's just a jet and needs to be fully seated to operate properly.

[PoorComa]

I'm not sure what that thread is all about, but it would appear that they are talking about a non-stock carb. I would ignore it. If you really want to check your slow air jet pull it all the way out. If there is a spring behind it you have the adjustable screw. No spring then it's just a jet and needs to be fully seated to operate properly.

Alright. I'll go ahead and set it all the way back in then, as there is no spring. Thanks for the info.

[SXP]

The requirement for an emission test caught my attention. As you might know, Ca doesn't allow us to plate dirt bikes anymore, so I had my 07 WR registered and plated in Phoenix. Does this mean I'm going to have to bring the bike back every so often for an emission test to keep up my registration??

[PoorComa]

The requirement for an emission test caught my attention. As you might know, Ca doesn't allow us to plate dirt bikes anymore, so I had my 07 WR registered and plated in Phoenix. Does this mean I'm going to have to bring the bike back every so often for an emission test to keep up my registration??

Yep, once a year if you plan to keep AZ plates.

[SXP]

Yep, once a year if you plan to keep AZ plates.

Bloody hell:bonk:

[Solo]

The requirement for an emission test caught my attention. As you might know, Ca doesn't allow us to plate dirt bikes anymore, so I had my 07 WR registered and plated in Phoenix. Does this mean I'm going to have to bring the bike back every so often for an emission test to keep up my registration?

Only after the bike is 5 years old. On another note AZ is working on removing emissions testing from bikes. Technically the law passed but there is some time before it will go into effect. If you're ridding an '07 you'll probably never need to get it tested. ?

PoorComa you shouldn't have much problem getting the bike to pass if it's tuned right. Mine flew right through testing. PM me if you still need help since I don't come in this forum very often.

You could also look at posting your questions in the Southwest forum since it's dominated by AZ people.

[GCannon]

Poorcoma:

see if you can get access to an exhaust gas analyzer at your local auto repair station or through your MMI buddy. put a fan on the radiator.

Then with the sampling probe in the exhaust adjust the fuel screw #24 and pay critical attention to CO2 not CO by maximizing CO2 you will bring both HC and CO into balance at the critical mixture for combustion (or emissions) you will not notice much differnce in the way it idles since you will be making very fine adjustments when it becomes close to the optimal point.

I have done this and it is amazing how much the numbers change without much change in the way it idles. tunning by ear will not get you close enough for emission testing even when the bike seems to run well.

Good luck and let us know how it goes.

[PoorComa]

Today I took the carb back off to check jet sizes and clip position and this is what I found:

Pilot Air Jet: #75 (stock) *I had this 7/8 turn out but have now turned it back in completely*

Main Air Jet: #200 (stock)

Clip: #4 (#3 stock)

Pilot Jet: #42 (stock)

Starter Jet: #65 (stock)

Main Jet: #160 (#165 stock)

What should I be looking to change to get this thing running a bit leaner?

-Kevin

[byggd]

Clip: #4 (#3 stock)

If #4 is counting from the top move it back to #3. This will drop the needle farther into the main jet and lean it out some.

[PoorComa]

If #4 is counting from the top move it back to #3. This will drop the needle farther into the main jet and lean it out some.

That was the first thing I did but wasn't sure whether moving it up to clip 3 would make it leaner or richer, I assumed leaner but thank your for confirming. Seems to run just the same though...guess you can't really tell without an exhaust gas analyzer or a wideband A/F sensor at least.

[krust36]

You are only being tested while your bike is at idle. The three carb settings that control mixture at idle are: Fuel screw, pilot jet, and pilot air jet. The rest of them you shouldn't have to worry about for the purposes of passing emissions.

You listed that your jetting is currently stock. Is the bike still stock, or have the free mods been done to it? Does it still have the ACV (octopus)? The free mods - especially removal of the ACV can have a significant effect on the jetting.

[byggd]

You are only being tested while your bike is at idle. The three carb settings that control mixture at idle are: Fuel screw, pilot jet, and pilot air jet. The rest of them you shouldn't have to worry about for the purposes of passing emissions.

You listed that your jetting is currently stock. Is the bike still stock, or have the free mods been done to it? Does it still have the ACV (octopus)? The free mods - especially removal of the ACV can have a significant effect on the jetting.

Correct. Sorry I didn't know the test was only at idle. Check out the link below, page 3 shows what jets affect what and when.

http://www.motorcyclecarbs.com/carbs101.pdf