Spark plug reading

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#1
What is the right color for a 4 stroke plug? A bit harder to read that 2 smokers. Bike is '01 klx300R. Plug is brownish on tip, off white inside. No black on plug at all. Could this be lean, or o.k.?Have done the KLX simple mods (remove snorkel, baffle, pcv valve and needle change).

Thanks,

Mark
 

kevkon

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#2
Do you mean that you actually changed the needle to an adjustable one or moved the clip position?

If you go to one of the spark plug mfg. sites they usually have a spark plug reading section with pics which will show you what to look for.
 
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#3
Kevkon,

As I'm in sunny California, changed the needle to adjustable, and set clip one up from bottom of needle. Was starving a bit at middle position. Pilot is 2 1/2 turns out Good idea to check the plug sites. Most of the moto sites only show 2 stroke plugs.

Mark
 

kevkon

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#4
What is the main jet size in your carb? Stock for the 49 states model is a 128. When my bike had the mods you have I went to a 130 and kept the needle position @ 3. Did you do any exhaust mods?
 
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#5
Just checked the ngk plug site, and was happy to see that things are right on NGK Site You know, this internet sure can be handy at times.

Mark
 
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#6
Originally posted by kevkon
What is the main jet size in your carb? Stock for the 49 states model is a 128. When my bike had the mods you have I went to a 130 and kept the needle position @ 3. Did you do any exhaust mods?
I've got the 128 main. Think I may try the 130 and middle clip position. Dropping the clip one did help, but there is still a very slight flat spot mid throttle (noticeable on the street, not in the dirt). For exhaust, removed baffle and nothing else.

What exhaust are you running, and what do you think of it?

Mark
 

kevkon

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#8
Currently I am running modified oem pipe and the stock silencer with a downturn tip from stroker. In my part of NJ, quiet is a little more important than absolute performance. I know fmf has a new "quiet" pipe out, but I am not overly impressed with their products or claims. In any case I don't think the setup I am using is too restrictive, just a little heavy.
 
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#9
Kevkon,

O.K., I'll bite. What modifications did you do to the oem pipe?

I agree that quiet is good, and don't mind a few extra pounds if it saves a bunch of dollars.

Mark

p.s. Read the Jenning's spark plug article. Made it obvious how little I know about jetting and plug reading beyond the butt dyno.
 

kevkon

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#10
The problem with the stock header is that it is too restrictive at the head flange. Take yours off and see how much excess weld fillet is present. Port this opening with a die grinder and you will be surprised at the improvement.
 
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#11
Thanks for the tip. Sounds like a good excuse to get some new dremel bits. Did you need to reinforce with welding outside, or was there enough on the outside of the flange? Love diy projects like this.

Marik
 

kevkon

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#12
You really can't reinforce the outside as you will see when you remove exhaust flange collar. There still seems to be plenty of weld area left anyway.
Definately by some new stones, I used an air die grinder and it was tough going. I am sure the amount of fillet to remove varies from bike to bike, mine ranged from 1/8" to 1/4".