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Plug reading - seems close, but wet

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The electrode area is a chocolate brown (hopefully you guys can tell from this pic) but the threads are pretty black and wet. Bike seemed a little rich on bottom and a little lean mid-top. I had to turn the idle up to finally keep it from wanting to die the second I let off the gas.

1400897185051.jpg

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Having oil on your threads in normal.  Plug check is for your main jet.  Yours looks a tad on the rich side, but close.  What are you jetting, and what are your settings?

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Bike specs?

 

2004 CR250, PWK air striker from JD (long body, no TPS), stock reed cage, just Boyesen replacement reeds, FMF Fatty and Powercore, stock motor with '05 base gasket. I don't have an hour meter, but I have about one year on the top end, which for me isn't really all that much. I'm going to re-ring it here in the next week or two, and as long as everything is within spec I'll leave it at that.

 

Riding anywhere from sea level to 750', temps are anywhere from 65-90 in spring/summer. High humidity. Jetting settings are 178, 45, JD red #3, 1 1/2 32:1 H1R with 50/50 Sunoco 110 and non-ethanol 93. Usually run the standard 8 plug, will run a 9 plug tomorrow at the dunes. I usually only ride MX, with the occasional trip to the sand. Re-packed the silencer last week.

 

Bike seems to run great in the cold months, but I have a really, really hard time finding good settings in the hot and humid months. When it's 80 and almost 100% humidity, I end up running really rich, but worry about leaning it out too much. Hence the darker colored plug. No air leaks that I know of. Both crank seals were replaced last year, no reason to think that either is failing. 

Edited by JDubya381

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Do you have the spec sheet for JD's needles?  If you don't, PM me with your email, and I will forward you a pdf copy.  According to JD's spec sheet, you are too rich on the main.  175 is recommended.  I'm running an 06 CR250.  I found the red needle was too lean on the bottom, and I'm riding in similar altitude/temps.  Try the Blue needle, 3rd or 2nd clip, 45, 175, and 2 turns.  This setting works well for me for MX or aggressive riding.  Not my best setting for slower technical single track.  

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Do you have the spec sheet for JD's needles? If you don't, PM me with your email, and I will forward you a pdf copy. According to JD's spec sheet, you are too rich on the main. 175 is recommended. I'm running an 06 CR250. I found the red needle was too lean on the bottom, and I'm riding in similar altitude/temps. Try the Blue needle, 3rd or 2nd clip, 45, 175, and 2 turns. This setting works well for me for MX or aggressive riding. Not my best setting for slower technical single track.

Yeah im actually gonna throw in the 175 except for tomorrow, taking the girlfriend and her TRX 4 hundy to the sand dunes. I'm gonna run the 175 the rest of the summer at the MX tracks. I think I will mostly keep to the 2nd clip position also. I get best throttle respone there, maybe a tiny bit lean but I run quality gas and oil so I should live.

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Yeah im actually gonna throw in the 175 except for tomorrow, taking the girlfriend and her TRX 4 hundy to the sand dunes. I'm gonna run the 175 the rest of the summer at the MX tracks. I think I will mostly keep to the 2nd clip position also. I get best throttle respone there, maybe a tiny bit lean but I run quality gas and oil so I should live.

 

Just do 1 change at a time so if you are running the JD red needle in the 3rd clip position with the 178 main, just switch to the 175 main and test.  If it still feels fat, then maybe move the needle clip to the 2nd position.  If you make more than one change at a time, you won't know what change made the difference you are feeling. 

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Just do 1 change at a time so if you are running the JD red needle in the 3rd clip position with the 178 main, just switch to the 175 main and test. If it still feels fat, then maybe move the needle clip to the 2nd position. If you make more than one change at a time, you won't know what change made the difference you are feeling.

Yeah definitely, learned that from experience haha.

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Yeah definitely, learned that from experience haha.

 

One thing that I found really interesting from talking to James at JD jetting and also using his Jetting guide to simulate jetting changes is changing the main jet will affect your jetting as far down as 1/8th throttle.  So, you could leave the needle in the 3rd clip position and just change the main jet and have it affect your jetting quite a bit.  I am looking at going to the 175 main on my setup as well.

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One thing that I found really interesting from talking to James at JD jetting and also using his Jetting guide to simulate jetting changes is changing the main jet will affect your jetting as far down as 1/8th throttle. So, you could leave the needle in the 3rd clip position and just change the main jet and have it affect your jetting quite a bit. I am looking at going to the 175 main on my setup as well.

I've always thought I noticed a difference in performance outside of the typical effects a jetting chart would indicate. Good to know.

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Here's today's plug from the dunes. Ran the BR9 to try and keep the temps down, ended up leaving the red needle in at the 3rd Clio position, 178 main 45 pilot. I checked it once halfway thru the day and it looked good, just a little bit lighter brown in the middle. Looks pretty good now, maybe just got loaded up more my last ride out u was practicing slow wheelies.

One thing I accidentally did was not put the plug cap on all the way when I checked it mid day. That advances timing, right? Would that have caused some detonation?

1401075411936.jpg

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What slide number?  That has a noticable effect on the bottom third of the jetting too.

 

Another way to test jetting is to watch the amount of white exhaust smoke.  Cruise down a straight section holding the throttle at a steady position, and have someone ride right behind you.  There should be very little white smoke when the engine is at a steady RPM and throttle position.  Obviously ignore the initial puff of smoke when initially accelerating off of idle.

 

I wouldn't get too concerned with jetting.  You are in the ballpark, so as long as you aren't foulding spark plugs you're fine.

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What slide number? That has a noticable effect on the bottom third of the jetting too.

Another way to test jetting is to watch the amount of white exhaust smoke. Cruise down a straight section holding the throttle at a steady position, and have someone ride right behind you. There should be very little white smoke when the engine is at a steady RPM and throttle position. Obviously ignore the initial puff of smoke when initially accelerating off of idle.

I wouldn't get too concerned with jetting. You are in the ballpark, so as long as you aren't foulding spark plugs you're fine.

I don't know what slide, which ever slide came with the 2000 CR PWK.

And yes I agree, I'm in the ballpark. I was having issues with loading up really bad yesterday because going down a loose sand whooped out trail I was just putting along in 2nd so I didn't leave my woman behind too far. So when I first crack the throttle it would sputter but then clean out and rev hard. What would be a safe way to solve this next time? Something that would allow me to putt around without loading up so bad?

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Possibly you could go a step leaner on the pilot jet. Try a #42 and see what the mixture screw says.

Okay will do. That seems lean for sea level in sand, but I do so much low RPM stuff, just kinda messing around with a girl on a quad, that I'm sure I'll live.

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