05 RM 250 white plug need help

[kathy127]

Have a new RM 250. Since new it has read a lean pinkish-white plug. Went from 168 to 175 on main jet and the plug is still white.
Went up a clip on the needle and it is still white. The only time it changed was when I put in a 2 step richer pilot and it came back blackish. But with this white plug, the bike runs great. No pinging, no surging, no nothing but a fun, fast bike !!!
But a white plug??? I am worried I will seize it.
Checked the cylinder for leaks-none.
checked the carb-fuel level right, nothing looks broken or chipped.
Checked the timing, it is spot on.
Radiator is completely full. No loosing water, no boiling over.
The bike seems perfect except for this white plug.
Only thing that is new to me is this carb selenoid. Does anyone know what it does and could it be the culprit???
Thanks for any help.

 

[Studboy]

First off, make sure that you are reading the plug properly. The top of the insulator mostly shows plug temperature, to check your jetting you need to cut open the plug and check the ring around the bottom. Do a plug chop and check the jetting ring on the plug and report back.

 

[marcusgunby]

If it goes darker when you up the pilot it means you are riding more on the pilot than you think.Its not the main you seem to be checking, you need to do a search on how to do a proper plug chop, i suspect you are not lean on the main.

 

[kathy127]

Maybe I said it wrong, it went black when we upped the pilot ONLY when it was ridden around the pits on the pilot. As soon as you go back to riding the track it is stock white.
The ceramic part of the plus is entirely white. No hint of any color all the way to the bottom.
But I will search a plug chop. We changed plugs 3 times just to make sure it was not the plug!

 

[elf]

I have seen 2 magazine tests on the 05 and both switched to a 165 main in hot wheather near sea level. So I would think the 175 would be to rich unless its realy cold in tx at this time of year.
The carb soleniod thingy your refering to is a throtle position sensor. This opens the power jet at the right time. If this was not working properly you would have a lean spot at a certian rpm, or throtle opening but it would not be lean across the entire range.

 

[kathy127]

that's exactly the problem, we've read those articles too. So we were shocked by the white plug when brand new. And it was 93' here yesterday and the plug with the increase in main from 168 to 175 still brought a white plug at the end of the fast straightaway.
I am wondering what else can be wrong to cause this. This carb solenoid says it affects everything except pilot so I was wondering if it could be bad. Weird thing is that the bike runs great.????? No ping, no detonation, no bog.
Maybe there is an air leak around the plug itself??

 

[WillyM]

white plug

When you say that you used a new plug did you use a NEW plug or different one.
Try a plug that is used and has some color it will tell the test.
If you have been running it for a while with a white plug I am suprised that it hasn't burned down by now, they don't last long that way.

 

[kathy127]

The 'new' plug was a new plug, but we put a used one back in and it too was white. I guess I am wondering what else can cause the plug to be white besides the jetting as changing the jettering seems to do nothing.

 

[Rich Rohrich]

The 'new' plug was a new plug, but we put a used one back in and it too was white. I guess I am wondering what else can cause the plug to be white besides the jetting as changing the jettering seems to do nothing.

What heat range plug are you running in your bike?

 

[kathy127]

It is the BR8Eg plug. But that is what is supposed to be in there as per the book.

 

[Rich Rohrich]

That's the correct plug, and a whiteish color on the nose of the plug means it's running at the correct temperature under load. The nose of the plug isn't the place to try and read the jetting strength.

I mean no disrespect, but it seems like you might not have a totally clear understanding of the factors that color the nose of the spark plug. There is a thread called Plug Reading 101 that explains it fairly specifically and has lots of pictures to help clarify the important points. Here's the link : http://dirtrider.net/forums3/showthread.php?t=92818

I think it might clear a few things up.

 

[kathy127]

I have learned alot about plug reading from the 101 to Gordon Jennings excellent article.
We'll have to do some new plug reading.
Maybe the bike is running so well because it is just right!!
It knows it, I didn't. Live and learn.
Thanks for all the help.

 

[Rich Rohrich]

IMaybe the bike is running so well because it is just right!!

Certainly sounds like it. :cool:

 

[bclapham]

ive leaned mine accross the board, 45P, 2nd clip, 162 main and its still a bit rich.

i have definately found that different oils and fuels will have a dramatic effect on the colour of the insulator and how much crud is on the top of the piston.

 

[_j0kA_]

you said you raised the clip one spot? that leans the fuel to air mixture and if your already running lean then you made it worse.. do plug chops to see how your jetting is and let us know

 

[kboy]

I have seen 2 magazine tests on the 05 and both switched to a 165 main in hot wheather near sea level. So I would think the 175 would be to rich unless its realy cold in tx at this time of year.
The carb soleniod thingy your refering to is a throtle position sensor. This opens the power jet at the right time. If this was not working properly you would have a lean spot at a certian rpm, or throtle opening but it would not be lean across the entire range.

A solenoid (powerjet activator), differs a lot from a potentiometer ( the princip of a TPS throttle position sensor) A solenoid is a "on/off" magnetic device, = it's open or it's not. A TPS sensor feels the slide position, in reality a stepless variable resistor. :cool:
TPS transmits a value , The solenoid recieves ....

 

[Bizerk]

I agree with joka, you mentioned that you "raised" the clip position which will drop the needle. Try lowering the clip position to raise the needle to give more fuel. My opinion is to try one thing at a time and not a bunch of things at the same time because you might get messed up even more and not know what helped and what didn't. Also check out Eric Gorrs site on tuning. :cool:

 

[kathy127]

When I said I raised the needle, I did not mean the clip, I meant that I richened the needle one step. And I spoke with Erik Gorr. The result of all of this seems to be that the bike is running perfectly. I just never knew that a visibly white plug was not only ok, but could be a sign of a perfectly jetted bike. The plug has a 'ring' after the chop test. And it runs great. And it runs with the visible ceramic part of the plug white. The metal electrodes are not 'wearing' or 'curving' on the edges. The bike shows no signs of running hot.
It only took 10 years of riding to have learned all this. Better late than never!