Author Topic: Plug Readings  (Read 2083 times)

cruz01

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Plug Readings
« on: March 23, 2009, 04:59:30 PM »
Well I put my engine together and I wanted to show some pics of what my plug looks like and get some input from you guys about what my engine is telling me. After I rebuilt the top end, I did a compression test and it read 130psi. I performed a leak down test and the engine passed. I fired her up and everything seemed to look good with no leaks of any kind. I followed hoser's advice on breaking the engine in and broke in the engine with a 25:1 ratio using Maxima Super M oil.

I ran a full tank and the engine acted fairly responsive throughout the break in. Throughout the break in, I checked the compression and it never got any higher than 130psi. I don't trust my compression tester and I'm going to use a reliable compression tester tomorrow. After I burned through the first tank, I changed the fuel/oil ratio to 32:1. From idle to mid throttle it ran fairly smooth but from mid to full throttle it would sputter here and there. Here are some pics of the spark plug from the beginning of the rebuild. I plug doesn't have a perfect brown or pancake color. The color is a little bit darker than the pancake color. I pics was the best I could do with my camera. By the way, the plug was new after the rebuild.

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PilotHawK

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« Reply #1 on: March 24, 2009, 04:40:23 AM »
Glad you got it running!

cruz01

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« Reply #2 on: March 24, 2009, 08:52:07 PM »
Any suggestions/ideas anyone??

hoodlum

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« Reply #3 on: March 24, 2009, 10:20:43 PM »
Quote from: "cruz01"
Any suggestions/ideas anyone??


Sorta hard to tell by pics...How long did you run the plug, and how did you go about the plug chop...Did you do it correctly?
Hoodlum

cruz01

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« Reply #4 on: March 29, 2009, 08:36:20 AM »
WOT for couple of hundred feet and hit the kill switch. It's kind of hard to do since I'm still breaking in the engine.

cruz01

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« Reply #5 on: March 29, 2009, 08:38:32 AM »
Well I have some results from today's ride and the frustration is mounting.....

Before I rode the pilot, I changed the main jet to a 142 and placed the needle on the third setting from the top in hopes to get the engine to run richer and then work down from there.

I fired her up and it idled fairly steady. After I warmed it up at idle, the throttle response was sluggish. From idle to 1/2 throttle, it bogged a little but it did accelerate. From 1/2 throttle to WOT, it bogged consistently. I checked the plug and it looked lean and extremely dry. I tried adjusted the air screw in small increments and it didn't help the bogging. Like I said before, I was riding the machine at about 3000 ft. with an outside temp of 68. I figured it would run somewhat richer than stock settings but it didn't and it ran like crap. Frustrating......

I replaced the main jet back to a 140 and adjusted the needle to the second setting from the top. The machine ran much better although it bogged a little in mid throttle. I did some plug chops and the plug looked lean and very dry. I stopped riding and went home.

I did an air leak test and pressurized the engine with 5psi. After 30min., the pressure dropped to 2 psi. I guess that would be considered an air leak but if the engine held air after 30 min, I think that's pretty good. Please correct me if I'm wrong. I checked the compression and its reading 140psi. I guess I still need some breaking in to do. I was running 32:1 ratio on 91 pump gas using Maxima Super M premix oil.

The only other things I can think of that can still cause a problem is I noticed that the needle is slightly bent. I don't know if this would cause the engine to run lean but its going to be replaced. Another possible culprit is the 142 main jet I used. The 142 wasn't a Keihn jet. It was an aftermarket jet. I went to three dirt bike shops and they all had the same aftermarket 142 jet.

I checked the fuel system and everything seems to be working properly. I cleaned the fuel filter and I have a new one on the way. I'm going to try using a different oil and see what happens. Any other suggestions?? I'm starting to loose faith with what I'm doing with my pilot. Any help would be greatly appreciated.....

PilotHawK

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« Reply #6 on: March 29, 2009, 09:19:58 AM »
Unscrew the plug cap and cut 1/4 to 1/2" off the end of the wire and either replace the plug cap or use the one you just took off and try again. You'll be amazed!

cruz01

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« Reply #7 on: March 29, 2009, 09:44:16 AM »
What will cutting the wire do?? Does the cap unscrew or do you pull it off the wire??

PilotHawK

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« Reply #8 on: March 29, 2009, 04:39:49 PM »
Corrosion. Unscrew and pull.