EGT Temps

[Odyknuck]

I am having an odd issue with my jetting and EGT.  No matter what I do with my jetting the EGT runs on the high side between 1200 to 1400 degrees in the mid range to WOT. I have jetted the main from a 165 to a 190 (Kehin Carb) and the temps remain about the same.  I have also change the clip position for mid range jetting. I know the jetting is making a difference because of the way it runs. It runs the best with the 165  and the worst with the 190 (too rich) and clip position runs best in the middle. The odd thing is that the when doing the plug chop routine the color is allways a shade of Charcol gray to brown.  My question is can the EGT be bad and still read, just not correctly. This is an analog EGT. Also why is the plug Grey? I have done jetting many times and have not seen thisa yet.

[PilotHawK]

A lot of the new synthetic oils burn much cleaner than the oils of the past so plugs are much more difficult to read. The EGT gauge you are using may be off a little and not reading correctly. Always jet to plug chops and note the EGT temps when you have the jetting correct to monitor your jetting without pulling the plug. If the EGT is faulty this will be nearly impossible though. I am making an assumption that you are running a 38mm carb on a ported and piped motor. If that is the case most machines I've seen with that set-up run best with a 165-170 main, and an DGH needle.

When running extremely rich you can get a faulty EGT reading due to unburned fuel burning in the pipe.

Jet to the plug chop and try a different EGT or jet for the conditions you will run lean in and forget about it the rest of the time. Don't use the EGT for a crutch you'll end up with a smoked top-end.

Hope this helps.

[Adnoh]

Do you by chance have any bogging issuses off idol or as you go to WOT from mid range. What heat range your running on plug and water cooled head or not. NO issues idol to mid just mid to WOT. If you are running big carb have you made any air mods. This will effect mid range as well as top end causeing you to run a lean mix. What bore and compression.