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Running fat... Why?

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When I first got my 93'. Found the plug was black.. Since then I replaced the plug with a iridium DPR8 EIx - 9. I did a snorkel removal, oil change, K&N filter, daves carb mod with 52/155 pilots (I'm at 5100 ft.). 2/14 turns in the screw. I also adjusted the int. and ex. Valves. What's going on or what should I do? Here is a picture :

By the way, the plug was fat before I did all this tune ups/mods too. The plug I took out was a DRP8EA9. I believe original jets were in bike. Picture of plug I replaced (1st pic is new plug, 2nd was the one that was in it when I bought it. Both fat.

image.jpg

image.jpg

Edited by dasanii19

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At above 5000 feet you are at the point of needing to go leaner. If you're riding area is even higher ask around and see what others are doing for their jetting or ask a local dealer. That plug is for sure is showing rich.

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I turned the mixture screw in one full turn putting me at 1 1/4. And the plug seems a little leaner. Should I be messing with this or focus more on the jetting?

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dasanii19, if the idle screw works (changes the spark plug from black to brown) then try it first. When it doesn't work even if fully turned in - then it needs leaner jets 🙂

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dasanii19, if the idle screw works (changes the spark plug from black to brown) then try it first. When it doesn't work even if fully turned in - then it needs leaner jets 🙂

Thanks, makes sense. Hers it is at 1 1/4 turns. 8AB34442-6B5F-470C-8778-6B271861A3EE-813-0000007616BFAD18_zps85592f99.jpg

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if yor riding at high elevations do the mods sans the jets, in other words drill slide and if you want cut spring so action is faster but you dont need to jet up if you know your riding mostly at high elevation...it goes against everything sensible

at most so starting is easier open fuel screw(with stock jets)

most xrl guys are using 52/155 now as a sensible middle ground...stock 152 if riding up...

that plug up top os bruning bad...you can see a big color change, meaning its running lean somewhere and really rich elsewhere...the tip should have a nice tan coloration onthe bend and the porcelain should be white until you see a nice tan ring on the bottom...you have to look way down the porcelain with a magnifying glass to see this or take it apart...

also look at the first 2 threads for color...

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looking at the 2 pics on the first post you can clearly see that the dpr8 stock plug and stock jetting has a browner tinge to it, clearly running better than the first pic...this is a clear indication that for your elevation stock main jet at least and a tweak of the fuel screw is all you need

I would not shim the needle either...

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Thanks for the replies, I went 1 1/2 turns (instead of 1 1/4) turns and rode to work and back today (20 miles freeway), pulled the plug and this is where I'm at now. What do you think? To me it looks real lean, I'm going to go another 1/2 turn putting it at 2 full turns. Again , the picture below was at 1/12.

CB04F147-678B-4396-847A-DC15D33C7FD3-2019-00000123ECA4F4D7_zps5ea69520.jpg

Edited by dasanii19

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I reread your first post. The plug you have is a NGK DPR8E. That is a hot plug not for highway use. Leave the mixture screw

between 1 1/4~1 1/2 turns and get a cooler DPR9E. I think all XR's use a 9 heat range plug.

Edited by ohio rusty spokes
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yup if you are commuting or blasting across the desert its dpr9 all the way...8 for normal use

that pic is showing an iridium plug...and the last pic actually looks pretty decent...the porcelain should be mostly white tanish, sometimes greyish depending on what gas you are using...

much better burning than the first pics....however I like the stock plugs better than the iridium ones...no point or purpose on our simple bikes...

op when taking pics of the plugs turn it 180 degrees so people can see the metal tab and bend...its there(I have been told many times) that you can see the color change...you should be tanish right at the bend of the tab...

like this:

xr010.jpg

This is on my xr6...people thought this was pretty decent overall(plug wasnt new however, just overall color) as well as my butt dyno, I was doing many plug chops at specific rpms because I had installed a different carb and was changing from dual headers to 2 into 1....which had a significant change midrange and lowend...

Edited by elsalvadorXR6
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here is another pic showing the greyish tan...new plug however...you can see that different fuels burn differently too...this was very similar jetting to the previous pic:

100_0965.jpg

sorry for the hijack...just helping!

christian

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The EPA wouldn't like that tan color but that is a much safer color than EPA white. White is too lean for an air cooled motor IMHO. Tan is perfect.

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oh I forgot...unless you are doing plug chops at a steady throttle on new plugs for at least 30 seconds all these pics are useless

you will be hunting for el dorado and never find it...

you can also simply do an overall chop by riding for at least 200miles...this will give you and overall plug reading that is ok since you havent done any major mods...

also the fuel screw should be in the 2 turn out range...1 turn or less means a step down leaner on the pilot...and then go to 2.5 turns out...most bikes like 2.5 turns out or 2.25 out...

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they are called fuel mix screws, common theory is that if its towards the engine its a fuel mix, towards the airbox or behind the bowl its an air mix screw...my flatslide was behind the bowl...however its adjusted like the kehin(per the manual)

Edited by elsalvadorXR6

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Post #10 says to use a DPR9 and post 10 says to use a DPR8. Am I readibg that right?

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dpr8 normal trail riding

dpr9 high speed or highway use, desert riding etc...

So I'm good with the plug I have in it then? I don't need to switch it out?

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Post #10 says to use a DPR9 and post 10 says to use a DPR8. Am I readibg that right?

The post says the 8 isn't good for highway use the 9 it's better for the highway because it is a cooler plug.

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