stupid jets are kiling me

[nissin 93]

hey guys heres the deal the guy i bought my quad from told me he had changed the jets when he put on my full team yosh exhaust whats in there is a 145 main and the stock pilot 22.5 i just changed out the 22.5 pilot for a 25 because the qued wouldnt idle and its popping all over the place now any suggestions on what i should be running in this thing i have a 2003 z400 with a full yosh about 200 above sea level please i need to fix it as soon as possible

[drnez]

Are you running with your airbox lid off? Are you using Mukuni or Dynojet jets?

A 145 mikuni main should be good if you still have your airbox on. With that 25 pilot, you should be able to turn the A/F screw most of the way in. If you're running without an airbox lid, try bumping up to a 150 or 155 mukuni main jet.

[nissin 93]

thanks drnez im running a mukuni 145with the lid on i went up to the 25 pilot because i couldnt get it to idle and now its bogging all over the rev range dont know if i should go to a 150 on the main or go back to the 22.5 pilot jetting is so annoying

[drzoo2]

You put the 25 pilot in which with the airbox removed should be on the edge of needing it. It sounds like the airscrew was never re-tuned after he put the exhaust on. Try tuning it with the 25 in it and see if you can. If you end up under a turn then put the 22.5 back in it and re do it. Do a search for adjusting the airscrew.

z

[nissin 93]

thanks for the info drzoo im going to mess with it today thats probably what it is i never even thought of it i was to frustrated i hate jetting it always confuses me

[nissin 93]

well ive tried everything that i can think of and so far nothing has worked still cant get it dialed right not with the 25 pilot or the 22.5any other suggestions or a way to fine tune it ide really appreciate it thanks

[blazinbronco]

elev. is 2000 ft here in las vegas nv. i have full exhaust system air filter system 25 pilot 146 main the new needle that came with dyno jet kit runs like a charm air fuel adj screw is 3.5 turns out at 200 ft level directions say 150 to 155 main check your directions or pull carb out and clean maybe dirt in the air bleeds

[450ERRRRRR!]

Make sure the clamps that hold the carb boot on are tight and not letting air in. I'm running with the lid off, 25 pilot and 160 main. all kelihn jets. Next I would bet you have a clogged jet. I take the carb off and remove the jets and spray carb cleaner into it. Then I'd blow the carb pout using compressed air from a can.
Good luck!

[honda6490]

Stock jet is 20 right, I just removed my airbox lid so it sounds like people recomend going up to a 25 if you remove the lid. I will also have a alba pipe in a couple weeks if i get the mount fixed. Thanks

[indyZrider]

woah! woah!dont just start calling everything a jet-stock pilot jet is a mikuni 22.5 almost everyone goes to a 25 when they add pipes and remove the airbox lid. stock main jet is a mikuni 136 or close to that. while jetting the next best thing to get is a 17 dollar adjustable fuel/air mix screw so you can adjust it with your fingers and not a pain in the butt tiny screwdriver. also another thing you might have to do is adjust your idle knob up a little to keep it from dying. you cant really test your jetting by revving in the garage either. take i out and butt dyno it. if it sounds like bogging it might just be bouncing the revs off of the rev limiter. also go get a bunch of jets if oyu dont already and start with a bigger one like a 160 or 165 dyno jet. if you need go to z400central.com and look for the conversion chart between the dynojets and mikuni's. its always better to be a little rich than lean. good luck

[honda6490]

How come I just took apart my bone stock untouched carb and the main jet is a 130 mikuni and the pilot is a 20 mikuni??? I have a 160 dyno jet that Im going to throw in today and just didnt know what I should get for a pilot (dynojet). Thanks

[honda6490]

WOw im stupid, this is so different than a 400ex carb. What screw is the air/fuel screw that I ajust. Thank you

[nissin 93]

got it all ironed out turned the fuel screw in to about 1.75 out and she purres like a kitten except on decelaration back fires every now and then still have to fine tune it slightly and i left the stock 22.5 pilot in

[Flynbryan19]

Try posting in the 400ex forum. Lot more people in that section with the exact same carb/motor as you. ;)

[drnez]

Originally posted by Flynbryan19
Try posting in the 400ex forum. Lot more people in that section with the exact same carb/motor as you. ;)


He's working on a Z400, not a 400ex.

[honda6490]

Yea sorry for the confusion I own a z400 now. Can somone post a picture or expalin in detail what the air screw is. I feel like an idiot but I just put in the 160 main jet and removed the airbox lid and its so lean it just revs up. I gotta richen the fuel/air screw but I have no idea what it is. I have jetted honda 450r's 400ex's and 450 bikes but I cant figure out where the screw is/ which one it is. Thanks for all the help I really appreciate it.

[indyZrider]

the air/fuel mix screw is under the brass plug that you have to drill out to get to. check over on the central for the pics of it. its a little plug to so dont drill too far and start drilling the mix screw.

[honda6490]

This is the plug with a little pin hole in the middle on the engine side of the carb??Thanks so much

[drnez]

Originally posted by honda6490
This is the plug with a little pin hole in the middle on the engine side of the carb??Thanks so much

Thats the one.. drill it out carefully, theres a screw about 1/4-1/3" under it.

[honda6490]

Thanks so much guys, I really do appreciate all the help i have gotten.

Ill let you know how things go.

Zach

[honda6490]

Ok ajusted the screw up to 3 turns out and it still revs up wicked high (lean im pretty sure) so i have to kill it. All I have done is put in a 160 main jet. I tried putting the airbox lid back on and it still revs up wicked high. Anyone know whats going on I have never had trouble with jetting and this doesnt make much sense.

Oh yea the 160 I put in is dynojet.

[honda6490]

Went out today with the 160 dynojet and everything else stock besides airbox lid removed. It was about 90 degrees and about 300ft elevation and it seemed to be running good except a rich low low end bog when you pinned it. Just wondering for a day that hot is it normal for the radiator fan to be on like almost the whole ride...mine was, but it never said it was overheating. I rode with my friend who has a 450r and he said his was barley on (normal for mine in normal conditions with stock jet setup). I will also be putting an alba pipe on soon, should I bump up the main jet a size or was it just on because it was such a hot day.

edit: Air Screw about 2.5-3 turns out.

Zach

[honda6490]

Just checked the plug and it was idea light brown. Im guessing I should prob go up to a 165 dynojet once I put the alba racing slip on, on. Since normal temps around here are like 75 80 for the summer should I lean up the fuel/air screw a bit as well to get rid of that low end rich bog. Like I said all day yesterday, 95 degree weather, the radiator fan was on while I was riding but the plug is light brown.

Zach

[450ERRRRRR!]

I'm running a 160 kelihn jet. I think the dyno is smaller so you need to go bigger. You really should go to the parts counter and get a OEM kelihn 160 main jet . I also bumped my pilot up to a 25 and it runs great. Mine runs perfect with a 160 and the lid off. I never had good luck with dyno jets.

[drnez]

Originally posted by 450ERRRRRR!
I'm running a 160 kelihn jet. I think the dyno is smaller so you need to go bigger. You really should go to the parts counter and get a OEM kelihn 160 main jet . I also bumped my pilot up to a 25 and it runs great. Mine runs perfect with a 160 and the lid off. I never had good luck with dyno jets.

Uhh, Keihin jets will NOT fit a stock Z400 carb, its a Mikuni.

[honda6490]

Originally posted by 450ERRRRRR!
I'm running a 160 kelihn jet. I think the dyno is smaller so you need to go bigger. You really should go to the parts counter and get a OEM kelihn 160 main jet . I also bumped my pilot up to a 25 and it runs great. Mine runs perfect with a 160 and the lid off. I never had good luck with dyno jets.

Yea a 160 kehein jet equals a 146 dyno jet which would be wayyyy to small because I'm running a 160 right now and dont even have my pipe yet and it runs good.

-Still have the question of once I put the alba pipe on it will probably lean out a bit right. Im running the 160 dynojet and stock pilot, plug color is cardboard brown (perfect) and theres a hair of a rich bog only when you punch it from a dead stop (rich fuel screw by a tad). I'm thinking I can get away with a stock pilot and just use the fuel/air screw to ajust that, but I wasn't sure if you guys thought I could get away with a 160 dynojet or if I should bump it up to a 165 or so.

Thanks,

Zach

[honda6490]

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