Who uses Colortune plug to set the carbs?

The Yamaha boys on the XJ list love them, I bought some mercury sticks, but may try them out this winter. Any thoughts?

Is this a see through spark plug? how much does it cost?

I just bought one off of EBay so we will see if it works for me or not.

Here are some USA distributers, no affiliation, blah blah blah.

www.eastwoodco.com/jump.jsp?itemID=2299&itemType=PRODUCT

www.aep.bigstep.com/item.html;$sessionid...%7C64347&PRID=911394

ok, how does seeing what colour the flame is determine jetting? is there a chart or something with colour and if its rich or lean?

I believe quite a few guys on the Concours forum use them and like them.

del

The principle behind the colourtune is the same as adjusting an acytelene torch or Bunsen burner. The chemical compounds produced during the various stages of combustion change the colour of the flame. Rich mixtures do not burn completely and produce a lot of carbon monoxide, which turns the flame yellow. Lean mixtures produce a hard to see bluish white colour, or don't burn at all. What we want to see is a nice bright 'Bunsen blue' colour -- named after, you guessed it, the Bunsen burner.

I am interested to learn how closely the observed "correct" flame color corresponds to the RPM peak. When someone decides to part with their $75 and plays with this thing, please report back.

And I take it that you can only use this to adjust the air/fuel screw for idle? How could you see this at WFO to check the main jets? :laugh:

spinalator wrote:

The principle behind the colourtune is the same as adjusting an acytelene torch or Bunsen burner. The chemical compounds produced during the various stages of combustion change the colour of the flame. Rich mixtures do not burn completely and produce a lot of carbon monoxide, which turns the flame yellow. Lean mixtures produce a hard to see bluish white colour, or don't burn at all. What we want to see is a nice bright 'Bunsen blue' colour -- named after, you guessed it, the Bunsen burner.

very cool, so we just need a video camera mounted above it to see it working through the rpm range under load....

Post edited by: 77KZ650, at: 2006/11/20 11:52

I bought it and used it twice. The first time it turned my #1 exhaust pipe BLUE! You're substituting your standard spark plug for this quartz-windowed plug that has simply a one-size-fits-all gap with a no resistance, metal-to-metal spark jump. The result is a *very* hot spark. It took about 10 minutes of running with this thing to turn my pipe blue. Agree with OKC_Kent, re: adjustments. This will only tell you *after the fact* if your main jets are set properly. Cute idea but not very practical.

And yes, it comes with a color chart.

I bought one but haven't tried to use it yet. I don't think you are supposed to run the motor for 10 minutes with them , but I could be wrong.

You use them after the carbs are synched.

Cut and paste from XJ source:

Back out the screw until the flame turns yellow, then slowly wind it in to get that nice blue with no yellow tinges. If you're tuning for best power and acceleration, then leave it there. If you're tuning for best economy, then mark the position of the screw before continuing to turn the screw in, counting the turns to the lean point. Back the screw out to a point 1/2 way between rich and lean.

For example, if it takes 1-3/4 turns to go from the first steady blue to the lean condition, then back the screw out 7/8 of a turn from lean.

The Colortune only adjusts the idle band of power. Yet the idle band affects throttle response and performance up to about 4500 rpm, depending on what carbs you have. This area was giving me the most headaches, so I thought I would give it a try.

Like I said I haven't tried it yet, but there were so many glowing reports from much better mechanics than me, I thought it was worth a shot.