Plug chop pics. Need your opinion.

[Jayy]

Hi, everyone. I just took pics of the plug chop I did on the outlaw chassis mx shee I am building. It revs out cleanly and I think I am rich enough, but could I be too rich? This is a proper chop after WOT in sixth on new plugs. The darkest ring around the base of the electrode didnt get that dark all the way around, but there is a dark ring there. It is hard to tell the smoke ring went all the way around the base because the entire center electrod was darkened. Let me know what you think.

 

One side.

 

 

Opposite side.

[RadarRacing]

That looks like it might be lean to me. I'd go up about 4 sizes and see if you can get a good ring down around the base of the porcelain to show up. Should be a 2mm tall darker ring. Some motors dont show a ring for a while till the plug is older. Some of the synthetic oils take longer too it seems. I like the cheaper oils to do chops. They show color better.

[Jayy]

If you look close, the ring is there, but hard to see because the entire center electrode is darkened quite a bit. This was with 340 mains. When I ran with 320 mains you could see the ring better because the entire electrode wasnt darkened from one chop run. Are you sure its not rich?

[Jayy]

Anyone?

[Jayy]

Anyone?

[Animalman294]

HAve you modified the intake at all. When I first put my cubby in I had to modify the filter's by moving them back in the bike with extension tubes and my plugs looked like your upper right and the other the bottom left. Now I was told that my modified tubes between the carbs and the filter's (to clear the exhaust so it wouldn't burn the outerwears) I was infact introducing vortex's inside the carbs and it messed up my plug chops. Removed the tubes and hooked right onto the carbs and problem solved.............

[Jayy]

HAve you modified the intake at all. When I first put my cubby in I had to modify the filter's by moving them back in the bike with extension tubes and my plugs looked like your upper right and the other the bottom left. Now I was told that my modified tubes between the carbs and the filter's (to clear the exhaust so it wouldn't burn the outerwears) I was infact introducing vortex's inside the carbs and it messed up my plug chops. Removed the tubes and hooked right onto the carbs and problem solved.............

 

Thanks, Animalman. Yeah, The intake is not stock. This bike has a custom fab aluminum airbox, no lid, and huge 2.5 inch aluminum breather tubes going to the carbs. The filter is a twin air filter off of a YZ 250 dirtbike. The motor is stock port, +4 timing advance, Pro Circuit pipes, but it breathes WAY more than a stock shee. The plug chop above was with 340 mains, stock needle on center clip, and 27.5 pilots with airscrews 3/4 turn out from seated. It runs clean through to the top and I have tried the choke trick at all throttle positions and speeds and it bogs whenever I pull the choke. I think it is jetted ok/safely rich, but the difference in how this thing breathes makes me hesitant.

[ABL]

Take a look at the bottom of the electrodes. For snowmobile tuning color can vary and light brown to gray is right on the ragged edge (where you want) the electrode should have a silver ring around it. That is indicating it has enough fuel to stay cool.