you win taffy, i have a few ? for ya

alright, so after ridding in the woods yesterday in some of the tightest single trak i have ever been in, i can really notice the bog at the bottom. your profile has you jetting specks but i don't get some of them. i see main jet, pilot jet and air screw. what are the others. here is what i am running . 178 min, 45 pilot, the "P" needle 3 or 4 clips down, and 2 turns on the air screw. i i ride in San diego and thats it. i have a 2000 wr 400 with it yz timed, no air box lid, and the white brothers promeg pipe (no disks) and the hi boy head pipe. i am willing to try your ideas on jetting but i want to know what the other stiff you have listed is. thanks

Hey Chris,

You could try the jetting in my signature. It's from and based on Taffy and his bike. I ordered everything from Sudco and only have the needle to fine tune. It has some popping at mid-throttle and I've dropped the needle to clip#6.

I have more info Sunday night.


MJ- main jet

MAJ- main air jet

PJ- pilot jet

PAJ- pilot air jet

FS- fuel screw

PAS- replaces PAJ (an adjustable screw)

SJ- start jet

[ May 01, 2002: Message edited by: Bill ]

well you're way too rich my friend. you'll find that if you're just rich you get a bog. if you're very rich the bog goes and the bike is just slower to rev and you can often hear the bwoooaaar noise from the air filter housing or whereever.

for your bike you need the following

160MJ with a 160MAJ. if you don't want to try the MAJ then a 168MJ will do it to go with your 200MAJ which is standard. it's up to you.

E_M or E_N needles are fine. i hear mattnohiohills has got 9 EMN's at his local dealers so give him a PM to find the dealer.

next we come to the pilot circuit. you can take it real easy and get a 38PJ and a 60PAJ or a 35PJ and a 45PAJ. i would buy the Pilot Air Screw instead of the PAJ's though. it's worth the extra lolly.

if you get an M needle then the 35/45 combo will be spot on. if you get the N needle then get 38/60 just in case.

as for the APJ well just disconnect it and set the bike up for a day or two and when it's sweet, starts first time and you can feel everything; reconnect it and set it to the smallest amount you can for it to function. make it start immediately you touch the throttle. no delay.

finally during those two days check how long it likes choke and report back. i ran a smaller starter jet in the end.

even the choke is tuned :):D:D !!

the gray wire is up to you etc. needle clip? well try the middle one.

don't forget that to experiment quicker you should run;

tall gearing

no rad flaps

one bolt in the tank

one bolt in the seat

both engine plates on the left

no apj cover

go for it over one day. get it sorted and then ride into the sunset.

jetting Qs tells how to test each area of carburation.


thanks for the info guys, ow and its a canada model so it had no grey wire.

ok, i am willing to what ever is best. and what is a APJ, ow and wich needle, n or m. also Taffy, where are you locaded. does the air, humidity etc make a difference.

take your choice with the needle but can't go wrong with the EMM needle. in jetting Qs there is a list of yam needles and yam do ELM i think so maybe you won't be in a qeue if you get it from them.

i live at sea level but don't worry it'll run fine with my jetting. all you need to do is add 10 to the MJ, ok?

you have a mk 2 carb so you will have to learn all about the BK mod. there is a guy over on the YZ426 side called motoman393 who has a website dedicated to this mod.

chris don't bust my hump, will you?


[ May 02, 2002: Message edited by: Bill ]

thanks again guys,

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