lean plug!!

[justinalley00]

I just rebuilt my topend and bored it to a 416 with the wiseco piston 11:1. My plug is very lean and I have adjusted the pilot jet to 3 turns out. I am running pump gas 93. I have checked for air leaks . anyone have any other ideas? Can you buy a bigger slow jet? Would adjusting the needle from 3rd to 2nd help?

[dalejiw25]

What size jets are in there now ????

[justinalley00]

#38 slow #148 main

[rubbersdown]

If your 3 turns out on your air/fuel screw than your a little lean, is it popping on deceleration (thats a lean condition)? I would up your pilot jet one size and try to keep your air/fuel mixture around 1 1/2 turns out.

[honda400ex2003]

Originally posted by rubbersdown
If your 3 turns out on your air/fuel screw than your a little lean, is it popping on deceleration (thats a lean condition)? I would up your pilot jet one size and try to keep your air/fuel mixture around 1 1/2 turns out.

he has a 416 lol gonna need at least a 165 if not closer to a 170-175 to even get started with a brown plug. go to a 180 and go down from there. get a 42 pilot, go 2.5 turns out on the f/a screw and you will be closer than at stock jetting specs like you are now. i cant believe it even runs with a 148 in it. steve:eek2:

[honda400ex2003]

heres some good reading for you

http://www.jetsrus.com/FAQ_rejetting.htm

steve

[speedfreek]

Arent you supposed to get a colder plug when you increase the compression ratio? Get one step colder plug and do as mentioned above and start with a 180 main and go down from there.

[honda400ex2003]

if he is running long wot runs or is in a very hot environment maybe a cooler plug is needed. most likely not for a 416 11:1. not many people do from what i have ever heard though. steve

[justinalley00]

Hey thanks Steve! that is a good read for jetting. is it really needed to change the plug after every change in jet size if the plug has no color ?What will changing the clip location due for me?

[honda400ex2003]

you wouldn't really have to change it every time if you can feel the difference. you should be starting out rich and going leaner so i wouldnt say it would be needed until you get closer to being good. i would think you shouldnt have to mess with anything needle wise till you know the main is good. just my thoughts on it though. once you start to get it close if it is popping or studdering in the mid then that would be the time to do the needle adjustment. going up on the clip leans it out, down rich. 2nd leaner, 4th richer. steve

[bherriman]

Originally posted by honda400ex2003
he has a 416 lol gonna need at least a 165 if not closer to a 170-175 to even get started with a brown plug. go to a 180 and go down from there. get a 42 pilot, go 2.5 turns out on the f/a screw and you will be closer than at stock jetting specs like you are now. i cant believe it even runs with a 148 in it. steve:eek2:


Wow, Steve I am a bit surprised you recommended that big of a main. I've got a 416 with a slip on, filter, and holes drilled in the lid, and I run a 155 with a 40 slow jet and approx 2.5 turns on the screw and I still think I may be a tad rich. Maybe I'm just way off. :confused:

Note: This is not a plug chop just about 20ish hours of hard riding.

[honda400ex2003]

looks good imo. i have only seen a few 416s run less than a 160 with yours being one of them. most are around a 165-175 mains. I ran a 170 for 2 years and had my plug look just like yours with even a bit more brown on the base than that. my 450 carb is the same way with a 165 in it. in comparison to yours, i think that my t4 probably flows better than your powercore does so that would increase it a main there. some run a bit more efficient than others such as my engine with the 450 carb on it vs. the 400 carb, and depending on your pipe, filter, lid or not, port job, and such it can be just about anwhere. many have to jet up to go to the 450 carb, i went down. if he is running a lid, he will be around a 165-168 probably when done if close to sea level. i dont know where he is since he did not give the info. I didnt fee like asking so i gave him something to get him on the rich side and work down. thats all that is for. steve

[bherriman]

I second guessed my self on the jets for a couple weeks so I stuck a 160 in it and it wouldn't even take off lol. The only way I could get it to run was using half choke and playing with the throttle. I stuck the 155 back in lol. I do have the slightest pop on decel but its not that bad and I dont want to turn the screw out anymore....

[honda400ex2003]

nothing wrong with that! every one is different thats for sure. :D it is night and day though once you start messing with it again after having it run great. you can really tell when it isnt running at its peak. lol then you want to mess with it all the time! darn it. lol steve

[justinalley00]

I live in Houston ,TX . I will try a 155 with A 40 slow to see where I am at . i have stock filter with the air box lid on. i do ride in the river a lot .