what kinda jetting u run

[TRX01]

ok guys, jetted my carb today....the only performance mods i got are a full pipe, and airfilter.....and im running 150 main and 40 pilot......well tested it out and if i hammer the throttle it wants to die/fall on its face, but if i ease into the throttle and nail it, it power wheelies like a champ.....my dad said that the air fuel screw might need to be adjusted but i just wanted ur guys opinions and wat kinda jetting do u run

[honda400ex2003]

i would say you are pretty close but could maybe go a notch up on your needle i am assuming you are on the 3rd position now and you would go to the second. i think this would help you out. just an option to try. steve

[TRX01]

ok thanks steve...more optinons and jeeting info please

[honda400ex2003]

also go to about 2 turns out on the f/a and see how it does. if it pops on decel then go out a 1/2 turn. how does your plug look after about 15 minutes of riding? steve

[TRX01]

actually got a new plug today thats going in tomorrow.........i no the plug i got now is really old

[honda400ex2003]

warm it up on the old one. then change it to the new one. take it for a ride for a good 15 minutes and then check it again. this will give you a general idea of what it running like. if you search for plug chop you can do that also to see how it runs at a particular place in your jetting. steve

[Rscarpantonio]

hey i need help, i bought a 400ex that had a blown top end replaced it and bored it to a 440 12.5 to 1 compression after riding it for maby 5 hours (2 seperate rides) i blew the head gasket ( did not put hd studs in, know i should have but o well, not the problem anaways) the reason it blew was becasue the sleeve was not flush with the top of the jug. but w/e sold that and am going down to a 416, it ran fine when it was runnig with the 440 in it but the thing i am wondering is am i going to need to change my jetting or should i be goodleaving the same ones in i had when i was runing the 440? all i have on is a slip on the new piston is going to be 11 to 1 compression i think and i eventualy want to put a hotcam stage 2 in if i can find one for a good price.
please help

[honda400ex2003]

found one from another thread

I was looking up a search on "Plug Chopping" And I think this will help you....


plug chopping
the plug chop is an essential step in setting up jetting. not only does it help you get good performance, but more importantly, it helps you make sure yr bike is not running so lean that it will blow up!

1. wind it out! . warm the bike up well (5-10 min) with a new or fairly clean plug, correctly gapped, then wind the bike out in a gear. generally, i like to do this in 3d, but it depends how fast yr bike goes in each gear and where y'r doing this test (trying to run a bike out in 4th is not advisable in, say, a school zone). at least get into 2d.

2. hold it there ... even though you will be nervous, hold it in gear at max rpm for a while... what you are trying to do here is simulate the hardest use the bike will ever conceivably see. if you jet for the most stressful conditions, then yr normal use will be well within safe margins. keep yr hand on the clutch, as you could (doubt it, though) seize if you are jetted too lean to begin with. as always, use yr own judgment!

3. kill it. simultaneously hit the kill switch and pull in the clutch. hitting the kill stops the plug sparking; pulling the clutch stops the clutch from turning the engine over (bringing in more unburnt fuel). thus, you get a perfect picture of what the sparkplug looks like at the moment you hit the kill switch.

4. pull over, pull the plug out you will want to have gloves or a set of pliers, cause the plug will be fking hot!!!

5. read the plug. if the plug is:

black and wet: yr jetting is too rich

chocolate brown: yr jetting is right on!
white and burnt smelling: yr jetting is too lean! upjet now . you might also notice a blistered insulator. this is real bad. you are lucky you haven't hurt yr bike worse!



steve

[honda400ex2003]

Originally posted by Rscarpantonio
hey i need help, i bought a 400ex that had a blown top end replaced it and bored it to a 440 12.5 to 1 compression after riding it for maby 5 hours (2 seperate rides) i blew the head gasket ( did not put hd studs in, know i should have but o well, not the problem anaways) the reason it blew was becasue the sleeve was not flush with the top of the jug. but w/e sold that and am going down to a 416, it ran fine when it was runnig with the 440 in it but the thing i am wondering is am i going to need to change my jetting or should i be goodleaving the same ones in i had when i was runing the 440? all i have on is a slip on the new piston is going to be 11 to 1 compression i think and i eventualy want to put a hotcam stage 2 in if i can find one for a good price.
please help

i would say you will def have to go a bit smaller to get it correct for the 416. I would start with something along what is in my sig. steve

[TRX01]

Originally posted by honda400ex2003
found one from another thread

I was looking up a search on "Plug Chopping" And I think this will help you....


plug chopping
the plug chop is an essential step in setting up jetting. not only does it help you get good performance, but more importantly, it helps you make sure yr bike is not running so lean that it will blow up!

1. wind it out! . warm the bike up well (5-10 min) with a new or fairly clean plug, correctly gapped, then wind the bike out in a gear. generally, i like to do this in 3d, but it depends how fast yr bike goes in each gear and where y'r doing this test (trying to run a bike out in 4th is not advisable in, say, a school zone). at least get into 2d.

2. hold it there ... even though you will be nervous, hold it in gear at max rpm for a while... what you are trying to do here is simulate the hardest use the bike will ever conceivably see. if you jet for the most stressful conditions, then yr normal use will be well within safe margins. keep yr hand on the clutch, as you could (doubt it, though) seize if you are jetted too lean to begin with. as always, use yr own judgment!

3. kill it. simultaneously hit the kill switch and pull in the clutch. hitting the kill stops the plug sparking; pulling the clutch stops the clutch from turning the engine over (bringing in more unburnt fuel). thus, you get a perfect picture of what the sparkplug looks like at the moment you hit the kill switch.

4. pull over, pull the plug out you will want to have gloves or a set of pliers, cause the plug will be fking hot!!!

5. read the plug. if the plug is:

black and wet: yr jetting is too rich

chocolate brown: yr jetting is right on!
white and burnt smelling: yr jetting is too lean! upjet now . you might also notice a blistered insulator. this is real bad. you are lucky you haven't hurt yr bike worse!



steve thanks for going out of ur way to find that info steve, but i no how to do a plug chop...had a yamaha blaster before i had the 400, and 2 strokes = non stop plug chops....mainly when mods were added or the seasons changed

[coreyownz]

Originally posted by TRX01
thanks for going out of ur way to find that info steve, but i no how to do a plug chop...had a yamaha blaster before i had the 400, and 2 strokes = non stop plug chops....mainly when mods were added or the seasons changed
i plug chopped my blaster once and never did my 400 yet.. im running a 150 main 45 pilot and stock a/f and clip idles so much better than stock

[TRX01]

i think i might need to go up on the main jet.....i ordered a 152 from the dealer today when i got my plug and 150 jet.....go thing i did, cause i think i need it........and corey i plug chopped my blaster many-o-times.......mainly with the seasons and cold and hot

[honda400ex2003]

no prob, hope you get it figured out. lol. steve

[coreyownz]

i couldnt care less when i had my blaster lmao but im running a 150 because they were out of 152's it seems to be running good. its such a pain to get the carb off on the 400's or im i doing something wrong? lmao

[TRX01]

well i did figure out that if ur just changing the main jet that is u undo the clamps and the air box tub and intake, turn the carb a little and take offf that big screw off the bottom and get and long 6mm socket on a quarterinch drive and u can take the main jet out that way and then change ur main, put that big screw back in, re-aline the carb and tighten the clamps back down and ur good to go.....but yea thats only if ur changing the main....
http://i49.tinypic.com/2j29ism.jpg

its that big screw i circled in red......and no thats not my carb, found the pic on google and edited it

[coreyownz]

i knew about that lmao that saves me on snowmobiles.. i mean to take the carb out of the frame were it seems to be crammed in and take the bowl off for the pilot

[TRX01]

i have little to no trouble getting mine off....i do have to lift up on the gas tank a little bit, and i find it easier to take the airbox out.....its one bolt and the clamp around the white snorkle.....its easy to take out and put back in and it gives u more room to move the carb

[coreyownz]

for mine i had to take the side panels off since my plastics are oem than lifted the gastank to were i could pull the carb out to the side of the frame and took off the bowl.