Idle impaired WR 400 !!! Help wanted !!

Ok guys here is my story....Pls bear with me... My bike is not idleling anymore since I`ve changed by stock pipe/header for a WB Hi-boy Header and pro-meg shorty(8 discs) and I have gone to YZ timing. Before doing these modifications the bike was ideling perfectly. Prior to the modifications the jetting was stock and.... all remained stock except for my main jet which I brought up to 172 (from 168) but that won`t change anything as fas as idleling is concerned.

I read a recent post on a bike that didn`t idle or hard to start and in there they mentioned that this problem could be caused by the throttle slide plate being upside down... I checked it last night and I had installed it correctly. My pilot screw is set at ~ 1.25 - 1.5 turns out and when I turn it out more the mixture is rich and there is an untolerable bog with black smoke so I`m figuring that I`m ok as far as the pilot cct but I could be wrong. I`ve also tried to fidle around with the idle screw but to no avail.....

So far I haven`t really done a test ride I`ve only tested on the bench... should I go out and ride it for 1/2 an hr to make sure it`s all warmed up and then chk the idleling ?? Aside from idleling, when I went through the throttle range it felt crisp and good thorughout the range. Another thing I noticed is that when I manually hold the choke 1/4 to 1/2 open it seems to be better.... Maybe I though that I brought the motor to operating temperature but I didn`t....

Any advise will be greatly appreciated.

thanks guys.


Your main is NOT the problem....You are now running Too Lean on the Pilot. If you havn't changed it (45) you need to go up to a 48 and the situation will resolve it's self.

OK TAFFY....I know, I Know, you advocate leaning the piss out of everything.

Take a look at the settings in my signature, They are perfect for my WR400, I run from sea level up to about 5000ft.

Good Luck...

Bonzai :)

:) well after that what can a man say :D:D

you take the high road an i'll take the low road and i'll get tay scotland afor yee!!!

Taffy :D

I would think that if I would need to go up to 48 on the pilot that my Pilot Screw would have to be out at least 3-4 turns ?? My screw is only 1.25-1.5 turns out and if I turn it out any further it`s smoke & unbearable bog..

So you think that putting in a 48 pilot and setting the screw at 3/4 would solve the problem ?? If so I`ll try that as I already have a 48... further more, I noticed that you have a 100 PAJ but mine is stock (75) so maybe the 48 will be too big ???

touch this

just read it and see what you think.


[ April 26, 2002: Message edited by: Taffy ]

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now