Is Muffler Color an Indicator if Jetting?



8 replies to this topic
  • MX974

Posted March 21, 2002 - 09:58 AM

#1

I just put a Thunder Alley on and was wondering if the gray color of the end of the inside of the muffler would indicate that it is jetted close to right. In other words black and sooty might indicate rich, light gray or white would mean lean.

I did put in a 168 main jet and didn't notice a change in power.

Thanks!

Jay

  • jamracing

Posted March 21, 2002 - 10:33 PM

#2

A plug check would be the best way to check this. You want very little residue on the pipe tip, but it sounds like you're doing good. You should try bumping your pilot one step (in conjunction with the BK mod), and going with a yz250f needle.

  • MX974

Posted March 21, 2002 - 11:05 AM

#3

Thanks Jam, Yeah a plug reading is always best, I was just thinking of a quick check. Is a BK mod necessary on a 2002 426? Most with the thunder alley just increased the main to 168 and didn't have to change the pilot and needle.

  • RichB

Posted March 21, 2002 - 11:33 AM

#4

There's a couple of different schools of thought on that. Many a tuner/mehanic have told me on 4 strokes the muffler is the best way to do it. I've also heard/read that if you're not running race fuel you can't get an accurate reading on burn from the plug (something about crap in pump gas). If it's runnin good and the muffler looks good than I'd say your good.

Late.

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  • Shawn_Mc

Posted March 25, 2002 - 09:01 AM

#5

When I was racing super stock flatbottoms we tuned with the collector colors. Problem is you really would need to see the color right at the reversecone exit way down past the muffler to be accurate. On the superstocks boats, we had all the access you could ask for at the plugs, but most of the time, tiny little jet changes wouldnt show with the race gas. The plugs simply looked new. We got to the point that I bought a periometer and tuned with the exhaust temps. The biggest problem with tuning today is, pump gas. To say its inconsistent is the understatement of a lifetime.

  • Shawn_Mc

Posted March 25, 2002 - 09:19 AM

#6

When I was racing super stock flatbottoms we tuned with the collector colors. Problem is you really would need to see the color right at the reversecone exit way down past the muffler to be accurate. On the superstocks boats, we had all the access you could ask for at the plugs, but most of the time, tiny little jet changes wouldnt show with the race gas. The plugs simply looked new. We got to the point that I bought a periometer and tuned with the exhaust temps. The biggest problem with tuning today is, pump gas. To say its inconsistent is the understatement of a lifetime.

  • John_Lorenz

Posted March 25, 2002 - 09:34 AM

#7

:) Personally, I have been running Thumpers, 40 inchers, 2 strocks since I was 9 years old I am 44 now. I grew up watching Mert Lawell, Jim Rice, Odom and all the greats. I never new any Racer that jetted there bikes by the color of the pipe. The best and most acurate method is to look at the plug. Erv Kenemoto explained to me once that the Plug is the heart of the Bike, With that he showed me the finer art of plug reading.

To properly jet you bike you will need pleanty of freash spark plugs. What ever you ride roadrace, woods, dirt tack or MX the best time to read you plug is when the bike is at running temp and you have just completed a full blown WFO romp around the Circut. Shut down the bike after the longest WFO straight, By Pull in the Clutch andby hitting the kill Button at the end of the run bring the bike to a dead stop with no throttle, free wheeling and dead.

Yank the plug out and check not only the ring but inside to look for deposits / crystals or anything that would not reseamble a good summer Tan on a Blonde Babe. The plug should be uniform in color and consistancy. Oily deposits or Crystals can me a few diff things. Hope it helps, I will look for a url to post on the look of plugs or a good Cramer manual will have the pics to compare. Install a new plug and try again until you get the results you want

:D Doing Me Best to keep the Piece

[ March 25, 2002: Message edited by: EgoAhole ]

Oh Ya Reading the plug is an art, you can tell what the bike is doing in all the ranges by looking down the throat of the plug. If it is black on the inside and brown on the outside, means top end run is good but Bottom & Mid-Range is running a little rich. If it is whit down the throat it is lean. So make adjust ments one at a time till its balanced.

[ March 25, 2002: Message edited by: EgoAhole ]

  • Taffy

Posted March 25, 2002 - 11:56 AM

#8

the plug reading was and still is the best way. but now that roadracers run unleaded and so do i you have to go by the pipe. open the pipe at the split and look up the tailpipe.

agree with everything that's been said.

Taffy

  • RichB

Posted March 25, 2002 - 04:28 PM

#9

Dude, I missed this the first time. R U saying that you didn't notice any power gain with that pipe or just didn't notice any diff switching to the 168 from the 162?


I did put in a 168 main jet and didn't notice a change in power.

Thanks!

Jay[/QB][/QUOTE]





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