Corrected Spark Plug "BASE" Reading

Its just really exciting, ripping the bike on the dyno. Then making jetting/timing/advance changes, and ripping it again...

A true testosterone thing!

:laugh: :laugh: :laugh:

okay fellows, heres goes. I'm new at all this on a learning curve. Last year after i got the motor runnig and road able . my plugs looked like plumman's fouled. I cleaned them many time and adjusted the carbs by ear. It got better,enough to ride approx. 1500mile last year. after reading the carb info,that rock,turn us on to today went at it again. i hope the picture makes it . these are my plugs before i don't know what size carbs ihave but after thinking that it not a mix screw but an air bleed, and open plug gap to .35 i went for rode test,after 20 miles returned home and pulled plugs.this what i saw bike ran grrrreat.i still have some small problems with it .but one at a time. thanks.

trying to get this img. thing down

Kind of hard to see in the images "fuzzy" but seem a hell of a lot better to me "Tan" in color versus black carbon...

Your base rings don;t seem to have carbon build up and have a full dark color ring that is desired...

On your ground strap though, not seeing the banding @ 1/2 way mark... This could be due to not enough miles on those plugs so don't worry about it but do keep an eye on them every 500 miles or so....

Example, on my new plugs right now, only 100 miles and decreased carbon build up with new YY9 needle in clip position 4 (richer)... Sweet! I'll run this setup for 500-1000 miles and then evaluate the plug conditions.
Change to clip position 3 (leaner) or leave at 4 will be the question...

If border line, I'll leave until summer where heat index here in AZ is painful (105-115) for I'd rather run a little on the rich side due to modded engine to keep her cooler...

NOTE: Possibly still have the oil cooler mod requirement... Due to now running synthetic oil, may not be required... Then again....

Anyhoot, glad the information may have helped out... Just remember, as written throughout the literature, better to be slightly on the rich side versus to lean... Plugs are cheap compared to blowing a hole in a piston

OMR

sorry about all the extra pic. should of be pics.of carbs. rode today 50miles plugs looking good. thanks again.

If you've got your main jet correct, then just move your needle clips up or down 1 at a time till you find the slot that gets the most power at half throttle and as long as it still transitions smoothly from idle, your done.

If your power keeps going up and you think that you need to go beyond the top/bottom clip positions, don't shim the needle. Instead, change your main jet accordingly and do some full throttle pulls to find the best main.

You need LOTS of jets. Several size ranges above and below the current jetting, in single steps.

I know, I know... long and challenging.

But when you eventually get it right, you will love it.

Remember, max power is not too lean. Power starts to drop off before jetting gets unsafe lean. Start what you think is rich some, then lean out from there.

Cheers, n good luck!

this is a deep subject.
!st off, it is impossible to make a call on the tune of a carb circuit from a plug that has 500 miles on it. at best u can look at it and say , well that's nice.
Dave , as u know, u have to tune 1 circuit at a time. That of course, means that the plug can only experience that circuit and that circuit only.
So are u testing only 1 circuit at a time?
the biggest puzzle is how many miles to put on the plug?
once u figure this out, u must put the same amount of miles on each circuit.
Explain to me , how u have been doing your tests and i will try to explain some of the pitfalls that u may need to overcome, to keep moving forward on your quest.
I spent a lot of time on this with my vm33's.
then had to revise the hole test method for the rs34's.i stopped reading the plugs and learned hoe to tune by feel:S

:S

Wouldn't changing the clip throw off the transitions? Why not just use a good starting size for the pilot jet and start increasing main size ( unless you have an air correction jet) until the plugs are the right color? I've never had many problems jetting. I'm sure it helped when I quit messing with the needle. I had a 155jet in my 1015cc motor and moved the clip up one. It needed lots of choke to pull in 5th gear and accelerated slow. I'm thinking the taper starts and ends at fixed locations on that needle. Needle moves when the slide is lifted. If one moves the needle it's no longer in calibrated relations with the rising slide. How can it possibly work better through all ranges since the amount of fuel entering the main body of the carb off idle is not nearly close to the required amount, calibrated by the physical taper and installed height of the needle? Is it safe to say when momma said it's time to come in from the sandbox it's after 10 oclock, it truely was past bedtime, it just wasn't realized by it's occupants. :woohoo:

mark1122 wrote:

When i started reading the plugs on my fresh 1200 with RS34 carbs. i got no color???? i always got readable results on my vm33's with the old motor??
hear is a pic of a couple of my test plugs.
1.the left 1 is a pilot circuit test, it ran on that circuit only for 7 miles(60mph@3900rpm)
2.mid pic is a main only test.145 mains 2 passes through the gears at wot.
3.The rt pic is just out of the bike after 4000 miles.it has a 127 main now, same pilot and needle as the others.

So the problem i had was. how many miles does it take to color a plug?
i think the best way to read a plug would be to tune it on the dyno then take it out and look. but they may have no color.
even when i was getting color on my last motor, i had to put several passes on a plug.

Another reason why I'm researching into this... :evil:

NOTE: There's no way in hell I'm tapping into my Kerker at the collector with a 3/4" hole!

Concept would be to design a 2" coupler interface tube with the 18mm sensor plug that would snugly fit in between the exhaust (muffler) and the header piping right after the 4-1 collector.

This way you can run the bike under loaded conditions and see exactly where she measures (AFR) in at...

Also been finding some interesting information regarding end of exhaust tube measurements vs. in between at the collector.

OMR

i have 1 of those on my wish list.
U can slide the probe into the end of the xht pipe , as far as u need to. u would need a sleeve of some kind to protect the wire though.
I heard that some dyno shops do it that way? It may not be acceptable for longer duration tests though.
I did a lot of plug tests. And in the end,I think the best way is by feel first. then if u want conformation, u start plug testing or o2 sensor .
1 only test 1 plug until i get it close, then verify the rest are the same. No point wasting 4 plugs per test. IMO.
I put tape on the grip, and mark off 1/8,1/4, 1/2, and 3/4 slide openings. Then when i do a jet test run, i make sure i am on that circuit only , through the test. Take the plug out and replace it with a used 1 for the ride home. I take notes on each jet change, about how the bike feels , while on an old plug, before i install a new plug and do the test.
As i mentioned, the trouble is how long do u run a test?
it only takes 10 sec or so to do a wot pass. not enough time to get color, unless u are WAY TOO RICH.
i didn't even get soot around the plug tread?
1 thing of caution, be careful about doing a lot of unnecessary tests. The threads in the head are aluminum, and NOT designed to have plugs put in and out many, many times. They will strip. Dont ask me how i know that.
I have done a LOT of plug tests.
I did learn a lot from it, but i think i learned more by trying to learn it by feel. Still learning.
What the plug tests did , was confirm my adjustments, but with this new motor i lost that, so i had to go by feel. now that i have some miles on it, maybe it will show color better???? I'll revisit it again next summer and see.