bad running machine [Archive]

cryan54935

03-30-2003, 07:05 AM

Is a 155 main jet too high for a 400ex.
It has an e-series with powerbomb, K & N.
I pulled the plug and it is black. It never started up very good when it was cold. When its warmed up its fine.
I have the stock pilot in there.
What should i do?

cryan54935

03-30-2003, 07:21 AM

Should i also mess with the chokeplate?

cryan54935

03-30-2003, 07:33 AM

Another question?

I was looking at a new Z and new Predator.

Are there any opinions on these two machines?

White_Knuckles

03-30-2003, 07:42 AM

Need more info. The "black" plug may mislead you that it's too rich as in the main jet. Did you test it by cleaning the plug with a wire brush and then perform a proper plug chop by warming it up and the riding a straight run at WOT, hit the kill switch and look at the ceramic insulator? The ring where the ground tang is attached is often black from rich idle and would be the pilot circuit.

Need plug readings and engine behavior at various points: idle, mid range and WOT. You may try adding and removing your air box lid to effect mixture and report results. How cold is your current air temp?

Good luck it's never a give away but go with tests not guessin'.

cryan54935

03-30-2003, 11:02 AM

Current temp now is 40 degrees.

I have no air box lid.