I will put your fears to rest

[z400clone]

OK good peoples, I have been stirring the pot lately with white plug posts. Thought I had to be lean. White plug, white exhaust on tip, red header for quite a ways back and others leading me to believe that it is lean. And my exhaust is really white coming out of the tip!

I have the full RS-5 ex.(SA pulled out), lid off, CB, 50% 110 octane race/50% 91 pump gas.

Well I spent the $$ to figure out what is up. This isn't my best run, but it shows the a/f ratio really well.



How do you like that a/f flatline jetting?

I think this might be my best run of 48hp and 33.5 ft/lbs of torque






For all the nay sayers that are saying these things are slow are full of poop. Piped only '06 450's, this is the fastest. I was asked on many occasions what all I had done. I responded that a pipe was all I knew that was out there really. If I was missing out on some new cams on the market, they should let me know. They quit with the probing then.



And b/c I spent the coin on the run, I'll go ahead and add one of my scrawny @ss just messin' around.

I am unclear, were you only running the cherry bomb. Or did you use a fuel controller? If so what brand?

[z400clone]

Originally posted by z400clone

I have the full RS-5 ex.(SA pulled out), lid off, CB, 50% 110 octane race/50% 91 pump gas.

that's it

[Mike Jones]

Is the spark arrestor a PITA to get outta the Yoshi silencer?

[DezSled]

Could you explain in laymans terms what the flatline means for the air fuel graph, I can understand the upper graph. What is the optimum a/f mixture?
I have been running 100% vp c12 just to prevent any problems and the exhaust tip is kinda white-ish still. Runs nice tho

[AceLtz]

From my understanding the red line is the optimum a/f at 13:1. The blue line shows what the engine is running at, below the line is rich, above is lean. From the lower rpms it looks a little rich. Other than that it looks dead on. Pretty even throughout.

[bwamos]

Aye. red line is 13:1. Look slike he's running 12.8 - 13.2. That's a pretty dang flat a/f curve. Very nice.

Still odd that at 13:1 it runs grey/white. Must have a very efficent combustion. Or perhaps the fuel atomizes better due to the injectors. I have no clue.. lol.

[z400clone]

13:1 A/F ratio is a pretty conservative ratio, but it was just kinda set as a baseline. Thumpers can take 13.5:1 no problem. Actually they keep making more hp the leaner you go 13.5:1-14.5:1, but I wouldn't go much leaner than 13.5:1 myself. Anyways, 13:1 is just kind of a standard. Good for 2 strokers to abide by, but the thumpers can push leaner #'s.

[slief]

Z400, Thanks for the info and nice picture by the way!

This seems like good news and would indicate that what Yoshi was saying was correct.. "Full RS5 with Sparky removed, Airbox Lid removed and a Cherry Bomb were safe and tested with 50/50 face fuel and super unleaded".

I was worried as I have a trip to the sand dunes coming up and thought I may be running lean as I have the above combo.

How important is the race fuel in the mix? It is a pain in the butt having a fuel station and needing to mix gas. I already do it for my sons KX65 and the last thing I want to do is carry another gas can in the Toy Hauler if I dont have to.

From what I understand, race fuel does not effect the air / fuel ratio. I know the higher octane would prevent pinging and from what I hear the race fuel makes it run cooler but if you are running rich, running cooler should not be much of a factor??
I have seen the glowing pipes but even stock headers will glow in the dark if the bike idles for a while.

[z400clone]

I have not ran it hard/raced with just pump gas. I did run straight 91 at home, but at the dunes is another deal. Way more load on the motor. I will let someone else see if the motor predetonates with a big load on it with 91 pump.......