Help..... Bad Misfire

Anyone know what might be causing this....

'04 WR450 symptoms:

At between 20-25 mph, seems to be a complete misfire or very bad stutter resulting in a jolt every 20 yards or so.... at higher speed it's OK.

Jetting - OK with PJ/PS/PAJ: 48/1.5 turns/100, Needle/Clip: EMN/4, MJ/MAJ: 170/200, LJ: 40, Idle: 1800 rpm (approx).

CDi output voltages - OK


Coil secondary winding - OK, unable to check primary winding as meter is not accurate enough.

Plug - OK

In the middle of checking all other wiring, connections, grounds etc - haven't found anything obvious yet.

Any help out there....


I know you say you've checked, but sounds like plug or bad ground connection to me.

Similar to bad ground connection, any water in the plug well?

Same thing is happening to me, but mine started after I put on a new exhaust

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