Plug chop on 350 Pro-X

[Travisg77]

What do you think of this plug chop?
Engine warmed up on old plug. Pulled plug and put new one in. WFO 1-5 held in fifth for 8 seconds. Shut unit down pulled plug.
When I go to set the pilot jet I can turn the AS out past 2.5 turns and my idle will continue to go up some. This seems to tell me that my pilot is still a liitle big. Does this seem possible that I need a smaller pilot jet then a 50?

1000' elevation
90 degrees
110 fuel
32:1 Klotz

PWK 39
Pilot: 50
Main: 182
DGH needle top groove (Still seems a little rich in the mid range)
NGK BR9EIX
A/S: 2 turns out
K&N/Outerwear with lid off
Head: Billet Pro-X
Porting: Not sure
Compression: 185
No leaks

Thanks!

[Fear250r]

Expensive plug to chop!!

[Travisg77]

Lol. Yea I know.  It's all that I had on hand.

[rbiron2]

From the pic it looks a little rich to me.... should only be seeing about a 2mm ring around the bottom and more cardboard brown... good start tho!

[Jerry Hall]

The engine RPM will be way past the power peak and out of the RPM range where the pipe is in tune with the engine when running it for 8 seconds in 5th gear.  The engine must be under a hard load and in the RPM range where the pipe is working.  Operating the engine in the RPM range where it is still accelerating up to the power peak is where the engine is generating the highest combustion temperatures. Combustion temperatures decrease rapidly after the power peak.

Most spark plugs will show what most  arm chair tuners consider to be rich when the engine is run in the over-reved mode for 8 seconds.  

 I would not waste any more money cutting good spark plugs apart to try to determine if your jetting is spot on.


The follow link talks a little about how misleading reading spark plugs can be and some of the common myths that are becoming accepted as fact in the internet world.

http://trx250r.org/threads/7326-More-power?p=67051&viewfull=1#post67051