To many changes, what jetting? spark plug pic

[ruffman]

Ive been reading about jetting for awhile now and my skull hurts.

Bike is a 2000 RM125 w/ V-Force, FMF Fatty and Shorty
Jetting is now:
Slow 48 (stock 50)
Main 170 (stock 175)
Air Screw 1 1/4 (stock 1 1/2)
3rd clip (stock 4th)
Basically FMF settings for just the pipe changes but I have also had the V-Force on for a few years now and hear that might have call for a leaner setting also (so confused)

Here's the plug after a new top end and 2 hours of trail riding.
3-4rth gear straight, many turns and 2 jumps (novice racing with friends)
http://home.woh.rr.com/ruffintrest/plug.JPG

The question is I have now bought some C12 replacing my 50/50 Turbo Blue 115 and Amaco pump gas 92

Doing reading on the C12 I have heard that you might need to lean alittle more.
What do you guys think?
At near $10 a gallon Id like to limit the trial and error time but dont want to rob myself of unused punch that a leaner setting might give.

I have just switched over to a Stock 02 YZ250 and its hard for me to notice the power of my little RM. Feels like an 80 now so not sure if Im going to get the same feeling of jetting ajustments as I did before and might make the wrong changes, if anyone thinks I need to do any at all.

 

[ruffman]

I guess I'll just stick with the FMF settings.
Bought a new plug today so I may better see the coloring.
If anyone has any feed back in leaning my jets now that I have added the C12 fuel.

Again Im running the FMF recommended jets as stated above but also have a V-Force and will start using C12 tomorrow, both of which in general can use more leaning if Ive read my searchs correctly.

Any comments or suggestions apricatiated

 

[hunter1]

Ruffman,

Check out canadian daves site on carb tuning at www.dirtrider.net/justkdx. The principle is the same for all 2-strokes.

 

[00rm125]

Ruffman, I also have a 2000 rm125 and have been chasing my jetting around. Today about 10 min ago, I went from a 175 main to a 170..... what a difference! The plug always use to be black and oily. I also raised the clip awhile ago and that really helped too. My plus is a nice tan now. I am running a 40:1 mix. The pic of your plug doesn't look nearly as bad as mine was. If anything, it looks on the OK side. Notice how the insulator on your plug is a golden brown? That's a good reading actually. How does the bike run..... any sputtering?

 

[ruffman]

Bike runs well, but didnt notice a big diff with the C12 vers the Turbo Blue. I ran a thread here a few years ago asking about the Turbo Blue thing in 2-stokes and I got a few mixed opinions. Been running it 3 years now and have had zero problems. Rings every 20 hours or under and a new piston at the 40 hour mark. Cylinder still has much of the factory cross-hatch pattern left in it and the carb is clean, so the theory of dirty gas or blowing up your motor being dirt fuel is out the window.

I'm guessing the 170 main, raising the needle one and using a 48 slow jet is a good setting regardless of Turbo Blue or C12.
Being that Turbo Blue is $4 a gallon and C12 retails for $10 a gallon makes it a simple choice.

The day after running C12 for an hour I checked the plug and it was a nice brown so Im guessing the jetting didnt need leaned as I was thinking using this cleaner burning fuel or the Turbo Blue I'm using isnt all that dirt/bad of a fuel.

I'll keep the above settings and stick with my TB fuel, Im happy there and keep alittle more money in my pocket :-)