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Wheeler

Carburetor Tuning..

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Well this was a surprise...

 

While the tank is off to replace my boot, I figured I’d ha e a look at my plug.. haven’t pulled it since I put my motor back together months ago.. however it seems to run great. Fires right up, have to move choke while warming up, but then idles great, pulls great, top end feels great..  I did notice other nite while testing the new light bar that the header pipe was “barley” hot even at the engine. Most of my running is mid range with some hard WOT short burps... so I’m thinking the needle may need to be lowered.. after hard accel I get the popped on decel... 

 

Considering how it’s really been running this was a surprise..

 

haha my sig says leaner is meaner.. she ain’t lean!

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Edited by Wheeler

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So because it "feels" like it's running great, my thoughts are this... humour me... any input appreciated...

 

 

The pilot is stock 300ex 38

Needle (from memory is 3rd clip)

Main is stock 122 or 118 what ever is in a 300ex..

 

So, I run mainly mid range but hammer it wot for spurts but never hold it there... 

 

This leads me to believe I should lower the needle first & try that, see how it runs... 

 

Then I'm thinking that my TOP end RPM according to my tiny tack WOT are down.. I'm not at the crazy 8750 I've hit.. I'm more like 7400-7700rpm now.. so that may lead me to believe that's why i'm down.. main needs less fuel.. 

 

I've learned over the years, to make one change, run er & see... what you guys think based of that little info...

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3 minutes ago, Wheeler said:

it "feels" like it's running great

 

IMO all these 300s run better and last longer with a slight rich mixture. Carbon deposits can be removed but wear is forever.

That plug is a healthy rich but not a "foul-it-out" rich.

 

My $0.02? Don't touch it.

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oh400ex... if you only knew me a bit better... !.. 

 

I can't have this.. black plugs or slightly carboned plugs are UNACCEPTABLE in my books.. 

 

I must make some tweaks & adjustments.. but this time well thought out ones.... 

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Haha I get the mentality but in practice you are likely just shortening the life of the bike. 

I don't put on performance parts for the same reason. If you want to wrench so bad you could have just got the Robin Blue... 🤣

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Do exactly as you were thinking. Lean the needle out one clip and see how it runs after. If its better leave it. Worse go back. You most likely wont have to adjust your main as the needle change is going to make some of that adjustment for you. Since you dont drag race and run wide open throttle real long your main isnt even showing on that plug. And you dont hold it there long enough to come entirely off the needle metering. My .02

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The needle is actually on the second one down.. gonna try er on the the top one... see how it goes..

 

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Edited by Wheeler
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Well boyz... I think that they may have done the trick... I've raised the clip to the top.. 

 

I live in the burbs... & took chance with cops & anyone calling them... Just went for rip around the block all over... Pulls harder thats for sure!! & throttle response seemed oh how would I say it... crisper/more responsive...RPM pulled faster too! I definitely didn't make it worse thats for sure!!! I'll run it that way for a while, then pull the plug. I didn't install new one... kept the carboned up one.. 

 

 

Edited by Wheeler
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Thanks for the update. I'm installing a new carb for my YZ 250 tomorrow. JD Jetting supplied me with extra needles and jets. Guess I will be tuning tomorrow.

 

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Well I’m still in bush putting the most amount of miles on the ole girl in a long time!! The needle change was amazing for power!! Here is how she looks after a few tanks of fuel.. same plug! I may play/tweak the pilot & main as well.. lots of backfire/pick/pack on deceleration.. so may need to richen the pilot up..

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thanks for the update ...  looks like it might need just bit more tweaking ... with popping  going on with deceleration   did you change out the oem exhaust ?? 

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