252wheelieking Posted May 18, 2012 Report Share Posted May 18, 2012 I installed my 421 cub, +4 timing, squish is .052 on right cylinder & .054 of left cylinder, compression on fresh build before starting was 130 psi on left cylinder & 132 psi on right cylinder. My compression guage tip is about 1/4" shorter than BR8ES spark plug tip. So my compression is higher than what the guage is showing. I mixed 100LL straight 32:1 Klotz supertechniplate & I warmed the bike up. Then I made a few passes with jetting set at 52 pilots CEG 162 mains. It was idle hanging so i installed a 55 pilots & it cleared up. I made a few more passes on it & checked the plugs & they was grey looking. I checked my compression again & the left cylinder is still at 130psi but right cylinder went up to 135 psi. The bike pulls good but i was nervous from the grey reading on both plugs. I installed a 170 mains & it got sluggish on top side. I removed the 170 mains & went back to a 162mains & it started back pulling hard again. So then I went to a 160 mains & it pulls a little bit harder. I stopped there cause I dont have any more plugs & was trying to find some help on dailing my jetting in perfect. I am concerned at why my plugs look grey? I know it's not lean or running hot just wondering why my plugs give a grey reading with the 100LL? & what color should my electrolode be when near perfect jetting....i know a tan brown using pump or race gas, but this 100LL is tricky....All help is appreciated Quote Link to comment Share on other sites More sharing options...
vulvafan537240 Posted May 18, 2012 Report Share Posted May 18, 2012 I installed my 421 cub, +4 timing, squish is .052 on right cylinder & .054 of left cylinder, compression on fresh build before starting was 130 psi on left cylinder & 132 psi on right cylinder. My compression guage tip is about 1/4" shorter than BR8ES spark plug tip. So my compression is higher than what the guage is showing. I mixed 100LL straight 32:1 Klotz supertechniplate & I warmed the bike up. Then I made a few passes with jetting set at 52 pilots CEG 162 mains. It was idle hanging so i installed a 55 pilots & it cleared up. I made a few more passes on it & checked the plugs & they was grey looking. I checked my compression again & the left cylinder is still at 130psi but right cylinder went up to 135 psi. The bike pulls good but i was nervous from the grey reading on both plugs. I installed a 170 mains & it got sluggish on top side. I removed the 170 mains & went back to a 162mains & it started back pulling hard again. So then I went to a 160 mains & it pulls a little bit harder. I stopped there cause I dont have any more plugs & was trying to find some help on dailing my jetting in perfect. I am concerned at why my plugs look grey? I know it's not lean or running hot just wondering why my plugs give a grey reading with the 100LL? & what color should my electrolode be when near perfect jetting....i know a tan brown using pump or race gas, but this 100LL is tricky....All help is appreciated I read somewhere that reading a av gas plug is just like regular gas except the plug will be gray vs brown. Can't remember if that was in the shouter the other day or on the site. So im guessing look for the thickness of the smoke ring on the plug vs color. Got pics of those plugs? Quote Link to comment Share on other sites More sharing options...
252wheelieking Posted May 18, 2012 Author Report Share Posted May 18, 2012 I read somewhere that reading a av gas plug is just like regular gas except the plug will be gray vs brown. Can't remember if that was in the shouter the other day or on the site. So im guessing look for the thickness of the smoke ring on the plug vs color. Got pics of those plugs? That was the other day in the shout when ddu or ddq, one of them said that the reading will be grey instead of brown. I just wanted to get a second opinion on the plug color. I will post pics of the plugs tomorrow. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted May 19, 2012 Report Share Posted May 19, 2012 i beleive the lead in the fuel is going to cause it to be grey and i would think you can read the plugs in the same form or fashion Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted May 20, 2012 Report Share Posted May 20, 2012 Dont go by electrode color. Some fuels are grey, some are even bright yellow depending on the fuel. Look at the smoke ring down in the plug. Its the one yoy can NOT see unless you cut the plug. That will tell you what you need to do. Quote Link to comment Share on other sites More sharing options...
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