Fastassbanshee96 Posted July 25, 2013 Report Share Posted July 25, 2013 I'm almost done building my drag bike. It's a 485 cheetah with 39s and sb off cpis. Dumps are drill to 120. What size main and pilot jet should I start with and what needle? Quote Link to comment Share on other sites More sharing options...
LCW Posted July 25, 2013 Report Share Posted July 25, 2013 What altitude are you at? Quote Link to comment Share on other sites More sharing options...
LCW Posted July 25, 2013 Report Share Posted July 25, 2013 I run my alky bikes a little rich on the pilot circuit, I'm at 2700 and I'm running a .125 main and 55 pilot in my 465 cub. Quote Link to comment Share on other sites More sharing options...
Fastassbanshee96 Posted July 25, 2013 Author Report Share Posted July 25, 2013 I'm at about 500 feet or so. What needle should I run. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 26, 2013 Report Share Posted July 26, 2013 I would suggest running possibly an EGN or richer down there. I'm running the EGN at the middle position up here. You do have power jets on those carbs? Quote Link to comment Share on other sites More sharing options...
Fastassbanshee96 Posted July 26, 2013 Author Report Share Posted July 26, 2013 Yes they have power jets. Now I'm pretty new to this stuff. How is it the needles work? I believe there is dgh needles in it now. Is the richer or leaner than what you said. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 26, 2013 Report Share Posted July 26, 2013 That needle is leaner than an E needle. The further towards the end of the alphabet you go, the richer. Start with your power jets wide open, which is the screw is backed all the way out. On alky you aren't looking for the color as you are more looking at the plating on the plug and the strap. The plating will tell you where your fuel is at the strap will tell you about your timing. Quote Link to comment Share on other sites More sharing options...
Fastassbanshee96 Posted July 26, 2013 Author Report Share Posted July 26, 2013 Now what exactly do you mean by plating? Quote Link to comment Share on other sites More sharing options...
Fastassbanshee96 Posted July 26, 2013 Author Report Share Posted July 26, 2013 Also what alky should I run. I was told m1. Is that good. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 26, 2013 Report Share Posted July 26, 2013 Where you are looking at the plating it is on the flat ring end of the plug. All plugs are plated in nickel or zinc I believe. Anyhow the ground strap is welded to that ring. As you get you fuel mixture right the plating will start to burn off of the end of the plug. Notice in this picture how there is roughly 40% of the plating still on the end of the plug. A safe tune is around 25% left. I shoot for around 5% left for my drag bikes. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 26, 2013 Report Share Posted July 26, 2013 You also need to be running BR"9"ES plugs. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 27, 2013 Report Share Posted July 27, 2013 Yeah, most run VP's M1. Quote Link to comment Share on other sites More sharing options...
fappy'97 Posted July 27, 2013 Report Share Posted July 27, 2013 Thank you, LCW! Info is much appreciated! Quote Link to comment Share on other sites More sharing options...
Fastassbanshee96 Posted July 27, 2013 Author Report Share Posted July 27, 2013 So with the plating.... Say you have more that 25% plating on it. Does that mean your rich or lean. Quote Link to comment Share on other sites More sharing options...
LCW Posted July 27, 2013 Report Share Posted July 27, 2013 So with the plating.... Say you have more that 25% plating on it. Does that mean your rich or lean. No, that means your air fuel mixture is close to stoich at wot. With alky, being rich the plug will have no plating burned off, or you'll see raw fuel out the pipes. If you are burning plating then your tune up is close to where it should be. What kind of timing are you running? Quote Link to comment Share on other sites More sharing options...
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