$5 per ride - plug fouling is getting old...

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Spikejr
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Re: $5 per ride - plug fouling is getting old...

Post by Spikejr »

Yep - the air screw is out 3/4 turn when I got the bike. I'm pretty sure the Jetting Guide said that 1 to 2 1/2 turns is good. If less than 1 turn, I need to put a larger PJ in the carb (currently a 38). I'm close at 3/4 and next weekend I'm going see if turning it open more makes any changes or if the air screw is correct where it currently is set.

Thinking about another race this Sunday...IXCR has a race so I might raise the needle clip one more spot to #2. I think the coffee color of the insulator is pretty much what I'm supposed to be getting...just need to know if the carbon that's on the metal threads is acceptable or not?

Also, I noted that the threads had some oil residue on them - except on one side of the plug where it was perfectly clean and shiny. Is there a reason that 1/4 of the plug threads would be clean and the other 3/4 of the plug oily? I'll post a pic that might show the issue...
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Re: $5 per ride - plug fouling is getting old...

Post by Spikejr »

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The clean threads are not because of a flash photo - they are actually clean and the area is shaped like a football. Any reason for this section to burn off cleanly?

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This is what the other 3/4 of the plug looks like - oily residue in the threads...
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$5 per ride - plug fouling is getting old...

Post by TAT2 »

Remember.... I am not an expert. But I think that plug looks bad...too rich bad. If your airscrew is only 3/4 turn out and running well....You need to go down one PJ not up. You need less gas to fix the rich plug. Again.... I am not an expert... But this is how I understand it.


Here is my plug after I dried it out by moving my clip up.....
Image


T
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$5 per ride - plug fouling is getting old...

Post by royadams »

TAT2 wrote:Remember.... I am not an expert. But I think that plug looks bad...too rich bad. If your airscrew is only 3/4 turn out and running well....You need to go down one PJ not up. You need less gas to fix the rich plug. in Again.... I am not an expert... But this is how I understand it.


Here is my plug after I dried it out by moving my clip up.....
Image


T
If 3/4 out on the screw is the highest idle, its on the lean side not rich. You use the plug color to check the main jet not the needle or slide. The needle and slide adjustments are more by feel. You really need to go step by step In the jetting process if you want the best an quickest results. Put a new plug in go wot in a high gear. kill the motor and pull the clutch in at the same time . Take a pic of the plug preferably with the threads cut off and post.
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Re: $5 per ride - plug fouling is getting old...

Post by Tedh98 »

Is your tranny fluid level dropping at all?
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$5 per ride - plug fouling is getting old...

Post by TAT2 »

royadams wrote:
TAT2 wrote:Remember.... I am not an expert. But I think that plug looks bad...too rich bad. If your airscrew is only 3/4 turn out and running well....You need to go down one PJ not up. You need less gas to fix the rich plug. in Again.... I am not an expert... But this is how I understand it.


Here is my plug after I dried it out by moving my clip up.....
Image


T
If 3/4 out on the screw is the highest idle, its on the lean side not rich. You use the plug color to check the main jet not the needle or slide. The needle and slide adjustments are more by feel. You really need to go step by step In the jetting process if you want the best an quickest results. Put a new plug in go wot in a high gear. kill the motor and pull the clutch in at the same time . Take a pic of the plug preferably with the threads cut off and post.

Ohhh gotcha....that makes sense now. Sorry to the OP! I am just learning this stuff too! I am at 1 and 1/4 turns out on my airscrew and response seems ok. I am not good at judging what lean or rich sound like.....

I have some new plugs and I am going to so some chops soon.

So why is his plug so fouled with carbon? Is that normal? Just a lot of low speed running that does that?
Mine has very been carboned up just more oily.

Thanks for helping us both out!

T
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Re: $5 per ride - plug fouling is getting old...

Post by TAT2 »

Tedh98 wrote:Is your tranny fluid level dropping at all?
Really glad you asked this! What does that indicate???

T
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Re: $5 per ride - plug fouling is getting old...

Post by Tedh98 »

If your crank seal (clutch side) is leaking it will be pulling tranny oil into the combustion chamber.

I asked only because it seems that your jetting isn't obviously rich. But I don't remember what elevation you are at.
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Re: $5 per ride - plug fouling is getting old...

Post by Julien D »

Tedh98 wrote:If your crank seal (clutch side) is leaking it will be pulling tranny oil into the combustion chamber.

I asked only because it seems that your jetting isn't obviously rich. But I don't remember what elevation you are at.
I had the same thought after seeing that oily plug.
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Re: $5 per ride - plug fouling is getting old...

Post by TAT2 »

Julien D wrote:
Tedh98 wrote:If your crank seal (clutch side) is leaking it will be pulling tranny oil into the combustion chamber.

I asked only because it seems that your jetting isn't obviously rich. But I don't remember what elevation you are at.
I had the same thought after seeing that oily plug.
my plug or the OP's plug?

T
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Re: $5 per ride - plug fouling is getting old...

Post by royadams »

TAT2 wrote:
Julien D wrote:
Tedh98 wrote:If your crank seal (clutch side) is leaking it will be pulling tranny oil into the combustion chamber.

I asked only because it seems that your jetting isn't obviously rich. But I don't remember what elevation you are at.
I had the same thought after seeing that oily plug.
my plug or the OP's plug?

T
Your plug does not look bad. That does not mean you dont have a seal problem if your losing trans fluid.
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Re: $5 per ride - plug fouling is getting old...

Post by Spikejr »

Sorry for the delay....unfortunately gotta work sometimes...

I appreciate the help - I plan to do some plug chops as soon as soon as I can find a long enough run to get them done...most of the areas I ride can only handle 3-4th gear...maybe some 5th gear...and I'm onboard with the PJ / airscrew discussion...

As for the oil level - I did notice a slight drop in the oil level over 6-8 hours of riding. The sight gauge had the oil approx 1/2 way up the glass when I had it filled, and I just serviced the oil and it was probably just visible at the bottom of the glass...I would say at the 1/8th mark. Saying it was at the 1/4 glass mark would be generous. Is that too much over that amount of time? Should it be rock solid at all times? When I get home I'll take another look at the glass...I serviced it very full before the race so maybe I can get an idea how far it dropped after 2 hrs...perhaps a leak down test would answer that question?
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Re: $5 per ride - plug fouling is getting old...

Post by Julien D »

TAT2 wrote:
Julien D wrote:
Tedh98 wrote:If your crank seal (clutch side) is leaking it will be pulling tranny oil into the combustion chamber.

I asked only because it seems that your jetting isn't obviously rich. But I don't remember what elevation you are at.
I had the same thought after seeing that oily plug.
my plug or the OP's plug?

T
Your plug looks good. The Op's plug is very oily after one run. That generally does not indicate a very healthy engine.

Yes. A leak down test would answer that question. You really should not be losing a noticeable amount of trans oil in a days worth of riding. At this point I would suspect crank seals, unfortunately.
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Re: $5 per ride - plug fouling is getting old...

Post by TAT2 »

Julien D wrote:
TAT2 wrote:
Your plug looks good. The Op's plug is very oily after one run. That generally does not indicate a very healthy engine.

Yes. A leak down test would answer that question. You really should not be losing a noticeable amount of trans oil in a days worth of riding. At this point I would suspect crank seals, unfortunately.
Will you lose some trans oil under normal good engine conditions?? Thx!

T
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Re: $5 per ride - plug fouling is getting old...

Post by Tedh98 »

TAT2 wrote:Will you lose some trans oil under normal good engine conditions?? Thx!
The short answer is no. If the level is going down, you either have a leak somewhere or it is being sucked into the engine.
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Re: $5 per ride - plug fouling is getting old...

Post by Spikejr »

Tedh98 wrote:
TAT2 wrote:Will you lose some trans oil under normal good engine conditions?? Thx!
The short answer is no. If the level is going down, you either have a leak somewhere or it is being sucked into the engine.
Well - that's a bummer...looks like a leak down test and then some searching for posts on changing seals...is the only downside that I'm fouling plugs or is there other significant issues with a seal going bad?
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Re: $5 per ride - plug fouling is getting old...

Post by Julien D »

Aside from hindering performance, being impossible to jet, and possible wear on the bearing journals? I ran my 89 for about a year with bad crank bearings and seals. I wouldn't advise it, but being a KDX, it WILL keep on running.
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Re: $5 per ride - plug fouling is getting old...

Post by Tedh98 »

When checking the oil level, make sure you do a couple of things to get an accurate reading.

Dont check it right after riding. Give the oil a chance to drip off the various parts and settle.

Make sure the bike is at the same angle when you make your comparison. Otherwise you can get different readings.
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Re: $5 per ride - plug fouling is getting old...

Post by Tedh98 »

Spikejr wrote:is there other significant issues with a seal going bad?
If the seal is worn enough, you will be sucking in the worn clutch friction material that is in the tranny oil. That wont be helping your cylinder and rings.
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Re: $5 per ride - plug fouling is getting old...

Post by TAT2 »

Tedh98 wrote:
TAT2 wrote:Will you lose some trans oil under normal good engine conditions?? Thx!
The short answer is no. If the level is going down, you either have a leak somewhere or it is being sucked into the engine.
Thanks so....

1. Leak ...somewhere? Crank seal most likely?

2. Being sucked into the engine...... isn't that what a leak does? Or is this something else?

T
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