Spark Plug Perfect, but still have spooge

[mlhend2002]

OK, I am somewhat confused. My 1994 KDX 200 has always run great from idle to wide open, but I always end up with spooge on my swing arm and fender after a long ride. I try to open it up every so often and keep on the gas, but I still end up with black crap everywhere. I use Mobil 1 MX2 (until I run out) at 40:1. Like I said, the bike is snappy from bottom to top rpm. With the modifications I have on my bike like FMF exhaust/silencer, Vforce II, etc. I have made adjustments to the mainjet, pilot jet and airscrew setting (2 turns out) as recommended by this site, by FMF and Vforce. Last weekend I put a new sparkplug (BPR7ES) in it and after my morning ride I check it. It was a golden brown, and no black, just like it suppose to be. I repack my silencer every few rides. There is no bogging down what so ever. Please help. :bang:

 

[_JOE_]

What fuel?

 

[mlhend2002]

91 Octane. I do get alot less with 105 but cost is a factor.

 

[jackflack44]

are you running too rich?

 

[_JOE_]

You won't ever completely eliminate spooge running pump gas. Any car fuel won't burn completely in a bike.

 

[SVandal]

If you aren't fouling plugs and your bike is running good through the entire range, then I would leave it alone. You may see about leaning out your oil/fuel mix a little, but otherwise I wouldn't bother it. Just clean it and ride and remember to clean the kips chambers every now and again between top ends.

 

[mlhend2002]

By running a hot plug NGK bpr7ES could I be masking running rich by burning up the excess fuel that would be left behind by a cooler sparkplug? How do you tell if the bike iis running rich in the low, mid or high RPMs. I need to know what too adjust, the airscrew, clip, pilot and/or mainjet. Thanks again

 

[dirt bike dave]

By running a hot plug NGK bpr7ES could I be masking running rich by burning up the excess fuel that would be left behind by a cooler sparkplug? How do you tell if the bike iis running rich in the low, mid or high RPMs. I need to know what too adjust, the airscrew, clip, pilot and/or mainjet. Thanks again

http://www.iwt.com.au/mikunicarb.htm Look at Figure 6 or 7, it has a visual for what parts of your carb effect different throttle settings.

The cutaway of your slide is important for below 1/2 throttle running, but few people will change this as slides are expensive. It is possible to grind some material from the bottom of your slide if you are a little too rich below 1/2 throttle, but there is no turning back if you grind too much.

Most folks with the KDX200 will run a '8' series spark plug. That is an easy change to make.

IMO, if the bike runs great and the plug looks good, the spooge is being caused by your gas, or residual spooge left over in the silencer from when you were jetted too rich.

Basically, a trail bike on pump gas is likely to spooge, mostly due to lots of low throttle running. It is much easier to get rid of spooge on an MX race bike at the track running race gas, so don't try to hold your KDX to that standard.