Rejet after drilling holes in airbox lid?

Jackpiner57

~SPONSOR~
Aug 11, 2002
356
0
I did a search and found no answer for this question.

First, my bike is a stock 2002 KDX200. No changes or adjusments made.

I drilled about thirty 1/4" holes in the upper portion of the lid all around the snorkle.

I noticed the following changes:
1. more noise
2. increase in power in the midrange and top end

I would like to know if this leans out the air/fuel mixture and is rejetting after this mod common?

I will check the plug tomorrow after work, but would like any opinions anyone might have.
 

G. Gearloose

Pigment of ur imagination
Jul 24, 2000
709
0
Yes.
Yes.

Had you already jetted for the stock airbox (that would be quite a trick), then you could be dangerously lean now.

If you started off completely stock, you are closer to optimal now.

However, there is still much to gain by persuing optimal jetting.

Checking the plug with any confidence is only relavent to a NEW plug after a WOT plug chop.
 

Canadian Dave

Super Power AssClown
Apr 28, 1999
1,202
0
In most cases removing or drilling the air box lid won’t cause a dangerously lean condition unless your jetting was spot on/ optimized before hand. That said it’s important to do a plug reading at WOT after you’ve made any changes to the intake or exhaust system on your bike to ensure the jetting isn’t lean.

If your KDX is still running stock jetting you’ll likely want to take the time to optimize the jetting as the stock jetting is very rich. Rich jetting = lost performance You’ll see improved gas mileage, better throttle response and performance with a minimal investment in jets and time. You can find more information on jetting on the JustKDX web page.

David
 

Jackpiner57

~SPONSOR~
Aug 11, 2002
356
0
Thanks for the replies.

I checked the plug today and the color on the insulator is LIGHT TAN.

I checked the NGK website and it says that it is OK.

I always thought that a light brown was better.

What do you think?
 

Jackpiner57

~SPONSOR~
Aug 11, 2002
356
0
Hi Dave, the bike is running great. I swear it has more power now too. I think the jetting was too rich before.

Thanks for the great forum!
 
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