jetting with 416, earlier discussion on 170 main being rich

[YZROOSTINYA]

i looked at my plug yesterday before changing to a new one when i did my oil


the plug is almost perfect. barely any carbon, even down the insulator. i run a 9 plug

its tan/black on one side and white/tan on the other side.

with the stock needle position and 165 main it was white and my header was glowing.

170 main
4th clip down stock needle
42 pilot
k and n with 6 one inch holes

i will see what the piston looks like when i do then valves in a few months

the plug is almost perfect. barely any carbon, even down the insulator. Thats a good thing.


its tan/black on one side and white/tan on the other side Wonder if the 9 plug is too cold and the combustion isnt even.


with the stock needle position and 165 main it was white and my header was glowing. Was this recently? could have been just a little lean due to the temp drop, I know mine was.

Remember that plug readings (except when its so rich its fully covered in carbon) can be misleading, and especially with pump gas.

Were you getting any lean deceleration pop with the first set up?

Dont you just love jetting, what a pleasure it is :)

[YZROOSTINYA]

it pops a little on decel but i know my exhaust leaks where the muffler meets the header and i think that is wha is causing it.

it was about 50 out when i had the 165 and stock needle

now its about 30 with the jetting i ahve now(170-4th clip)

the plug has been in there since i put the 416 in. i have not done a reading on the new plug.

i think it was kinda whitish from originally being lean, and now it is about perfect. the plug is supposed to help the head run 5 degrees cooler. i ride it pretty much wide open all the time. i put around on it too. but most of the throttle is either on or off:devil


if its still lean it also might explain why one side is okay(intake side) then other side white(exhaust)

???

wish i had a dyno and a a/f meter.

it doesn't seem to overheat(i dont even know what would happen if it did, detonation maybe?)

the oil looks good and it doesn't smoke at all.

before i did the topend i had a 155 main on a stock motor with the full exhaust and it was BLACK and carbony on the piston

[BadA$$440]

i got a 160, 4th clip down on needle, and stock pilot. It runs fine but seems alot hotter so i might go up to a 165.

[crazy canadian]

i'm running a 165 main, 42 pilot and i'm at 1800 ft above sea level. my 416 with port and polish runs real good. there is a real nice color to the plug also.

[YZROOSTINYA]

i just checked the plug again


light tan to dark dark tan

seems good.

[BadA$$440]

Where do you get your pilot jets at? And also, are they called the low jet cuz thats what it says in my manual

[YZROOSTINYA]

the dealer like $5.00

you have to pull the float bowl, its in front of the main and to the side i beleive.

i called it a pilot jet, thats what the guy gave me

[YZROOSTINYA]

http://www.servicehonda.com/HARD%20PARTS/ATV/TRX400EX/trx400ex%20frames%20page.htm

yeah #37 slow jet, same differance

Pilot jet/ Slow jet = same thing.

I am currently running a 50 pilot in the 440 but am thinking its a little too rich, but much better than the 58 the local guy talked me into earlier.

Most all the jets I have purchased have been around $5.00 except the few I got at a local Yami dealer who is a little nuts on pricing he wants $8.00 for the same stuff.

[BadA$$440]

50 pilot? Damn, i still got 38. Pilot controls idle-1/4 throttle right? Well i will go buy a 40 and 42 and see how they do.

[YZROOSTINYA]

just put in the 42 now that u have the 416