I would like to understand more about reading spark plugs that burn alchcol.
Is it true that the leaner the mix of air and fuel that the plug burns brown ?
I run a 600cc Honda in a Reatrictor class of mini-sprints and I have a tough time of getting the engine to idle and the performance doesn't seem to be all there.
My son that drives the car complains of the car loading-up because he see's flames come from the exhaust as he burps the throttle as he goes into the corner, And he has allso stated that he feels the car level off down the straight away, I have may be that part of the problem is the gearing we try to runcausing the restritors to come into play way early.
Restrictors, let me explain.
A stainless steel disc under the carbs and before the intake runner into the head.
Stock opening in the carbs bore is about 1.4 inches and the restrictors are a 3/4 inch opening.
I'm not sure of how this would affect the jetting of the carbs, as it stands right now i'm running a104 jet
and the clip on the needle is at its riches piont.
Any info would be greatly appreciated.[img]i/expressions/face-icon-small-confused.gif[/img]

 

running in restrictor class will mean the restrictor makes your motor suck for air a lot harder than it had to under normal conditions. That's probably giong to make it run RICH. I'd bet your carbs are way to rich if it's spitting flames under deceleration.

Can you get it on a wideband O2 sensor? MOst dyno shops have these - it will help tell you if you are running good A/F ratios. On a motor like this, you realyl should get it dyno'd or at least look at the A/F coming out the exhaust to get an idea how to jet and compensate for the restrictor. Think of the restrictor as acting just like a "choke." It will make the motor run rich - especially at high RPMs.